Madhu Murthy K | National Institute of Technology, Warangal (original) (raw)

Papers by Madhu Murthy K

Heat Transfer [Working Title]

Microchannel flow is an effective solution for many engineering problems. Application of microcha... more Microchannel flow is an effective solution for many engineering problems. Application of microchannels is found in various fields such as thermal management of electronics, micro-combustors, biomedical industries, MEMS. In microchannel flow, some internal and external influences such as surface roughness, electric and magnetic fields are very significant and commonly neglected in macro-scale flow. Early research works on microchannels stated that the conventional theories of macro-scale flow were not applicable for microscale flows. Finally, researchers are concluded that the deviation in conventional theories in the case of micro-scale flow is because of neglecting the internal forces, surface roughness, surface wettability, etc., which play a prime role in micro-scale flows. In this chapter, the behavior of microchannel flow under the internal and external influences is discussed. The heat transfer and hydrodynamic characteristics of microchannel flow under the external magnetic f...

Heat Transfer - Design, Experimentation and Applications, 2021

Thermal management of electronic equipment is the primary concern in the electronic industry. Min... more Thermal management of electronic equipment is the primary concern in the electronic industry. Miniaturization and high power density of modern electronic components in the energy systems and electronic devices with high power density demanded compact heat exchangers with large heat dissipating capacity. Microchannel heat sinks (MCHS) are the most suitable heat exchanging devices for electronic cooling applications with high compactness. The heat transfer enhancement of the microchannel heat sinks (MCHS) is the most focused research area. Huge research has been done on the thermal and hydraulic performance enhancement of the microchannel heat sinks. This chapter’s focus is on advanced heat transfer enhancement methods used in the recent studies for the MCHS. The present chapter gives information about the performance enhancement MCHS with geometry modifications, Jet impingement, Phase changing materials (PCM), Nanofluids as a working fluid, Flow boiling, slug flow, and magneto-hydrod...

Heat Transfer Engineering, 2019

In this article, a three-time level finite difference scheme is used to resolve the dual phase la... more In this article, a three-time level finite difference scheme is used to resolve the dual phase lag's (DPL) heat conduction in a micro scale gold film subjected to spontaneous temperature boundary conditions without knowing the heat flux. Finite difference analog of DPL equation on applying to the intermediate grid points of the computational domain results into a system of linear, algebraic equations which can be solved using Thomas' algorithm to finally obtain the transient temperature solution distributions in the film. The solution predicted by the DPL model is compared with that obtained by the single-phase Cattaneo-Vernotte's model. Further, the way in which non-Fourier's temperature distributions affected by the diffusion due to the increase in Heat Conduction Model numbers agree with the predecessor's published results. The results by both the models revealed a finite thermal wave speed in the film contrasting the infinite speed of heat propagation as stated by the classical Fourier's thermal model. Low spatial step and higher order finite difference schemes are recommended for better accurate numerical results of the non-Fourier's temperature distributions occurring in the very short transient period between the instants of the suddenly applied spatial temperature gradient and the reaching of the steady state conditions.

Energy, Environment, and Sustainability, 2021

The engine block is a crucial component of internal combustion engines since it provides the sour... more The engine block is a crucial component of internal combustion engines since it provides the source of power for the vehicle. The engine block is a solid cast element that contains the cylinders and their related components inside a cooled and lubricated crankcase. The majority of engine blocks are cast iron, a brittle rich material that can sustain greater variations and weights while also being vibration resistant. Energy is changed from potential chemical energy to mechanical energy in this step, which is heat produced from burning fuel in the form of mechanical energy. A large amount of energy may be lost during the firing of an engine. This must be assessed using CFD prediction techniques. For starters, significant thermal and structural stresses may be produced over the cylinder blocks and pistons. Prior to the fabrication of the specific Internal Combustion engine, the structural and thermal analysis aids in the failure analysis. The solid modeller Parametric-Creo is used to create the current and new engine block models. This technical chapter will cover the simulation and analysis of the structural and thermal consequences of each specified bore piston and cylinder block model. The effective stress and temperature analysis using the finite element method will be performed using current tools such as ANSYS workbench, ADSL, and Deform 3D, with the processes and analytical functions described utilising supplementary literature theories, which can be found here.

A zero dimensional model has been used to investigate the combustion performance of a single cyli... more A zero dimensional model has been used to investigate the combustion performance of a single cylinder direct injection diesel engine fueled by biofuels with options like supercharging and exhaust gas recirculation. The numerical simulation was performed at constant speed. The indicated pressure, temperature diagrams are plotted and compared for different fuels. The emissions of soot and nitrous oxide are computed with phenomenological models. The experimental work was also carried out with biodiesel (palm stearin methyl ester) diesel blends, ethanol diesel blends to validate simulation results with experimental results, and observed that the present model is successful in predicting the engine performance with biofuels.

Journal of Energy Resources Technology

The typical tradeoff between the two major emissions from compression ignition (CI) engines, smok... more The typical tradeoff between the two major emissions from compression ignition (CI) engines, smoke and oxides of nitrogen, is the unresolved challenge to the researchers. Techniques like engine downsizing, lowering intake oxygen concentration, multiple injections, use of retarded injection timings and higher injection pressures, etc. are widely employed for the alleviation of these harmful emissions. The influence of variation of fuel injection pressure (FIP), boost pressure, pilot injection timing (PIT), pilot injection quantity (PIQ) and main injection timing (MIT) are experimentally investigated in the present work. Mahindra mHawk four-cylinder diesel engine with provisions of a variable-geometry turbocharger (VGT), exhaust gas recirculation (EGR), and common-rail direct injection (CRDi) is chosen for the experimentation. Test runs are conducted at 1750 rpm and 80.3 N.m (4.6 bar bmep) corresponding to highway drive conditions, using 10 % EGR. Response surface methodology is emplo...

International Journal of Ambient Energy

Biodiesel from non-edible oil sources can be a promising solution to meet the ever-increasing fue... more Biodiesel from non-edible oil sources can be a promising solution to meet the ever-increasing fuel crisis and environmental degradation. Sterculia foetida is one of the less exploited biodiesel fee...

International Journal of Energy Technology

Day to day increasing vehicles usage for human activities is caused to accumulate greenhouse emis... more Day to day increasing vehicles usage for human activities is caused to accumulate greenhouse emissions into the environment. The biodiesel is a best alternative fuel to run diesel engines. But its lower Calorific value and higher NOx emissions makes the consumer should compromise with engine performance and emission characteristics. As we know, that the use of additives to improve engine Combustion and emissions are caused to increase the fuel cost due to the higher cost of additives. The biodiesel conversion process of third generation biodiesel is costlier and required technological advancements for qualitative fuel. In the present work, the author used mixed culture micro algal particles in Coconut biodiesel (CCNME+AP) to improve engine characteristics. The Brake Thermal Efficiency (BTE) was enhanced, and the NOx emissions were less due to the absorption of heat in the Combustion chamber, it led to cool combustion phenomena with the Algal particles contained Coconut Biodiesel (CC...

Proceedings of the National Academy of Sciences, India Section A: Physical Sciences

The day-to-day human needs are strongly associated with the transportation and industrial sectors... more The day-to-day human needs are strongly associated with the transportation and industrial sectors, which are influencing to deplete fossil fuel reserves. At this situation, the use of biodiesel in an efficient way is the only practical alternative to run compression ignition engines. The biodiesels fuel-borne oxygen may reduce carbon monoxide (CO), unburnt hydrocarbons (HC), and smoke emissions but increase carbon dioxide (CO 2 ) and oxides of nitrogen (NO x ) emissions. The scientists and researchers are starving to improve engine performance by reducing the most harmful NO x emissions. Because of this, the author has investigated naturally aspirated single-cylinder unmodified direct injection compression ignition (DICI) engine. Two grams of mixed culture algal biomass particles are added in highly saturated coconut and unsaturated Karanja biodiesel fuels. The brake thermal efficiency of algal particles-emulsified fuels increased due to the explosion of biodiesel-surrounded algal particles after attaining autoignition temperature. The reduction in NO x emissions is noticed with algal particles-emulsified fuels because the particles absorb heat from the combustion chamber.

Proceeding of Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)

International Journal of Ambient Energy

ABSTRACT Improved engine exhaust emissions with little or no deterioration in performance may be ... more ABSTRACT Improved engine exhaust emissions with little or no deterioration in performance may be achieved through the use of new technologies and/or modifying the engine hardware. Present paper details the attempts of an experimental evaluation of Kirloskar make TV1 type diesel engine equipped with common rail direct injection (CRDi) and electronic control unit (ECU). It is established that retarded injection timing and smaller fuel droplets simultaneously reduce NO x and smoke emissions of a typical diesel engine. Hence engine testing was carried out using diesel fuel at 1500 rpm, under 50–100% of full load brake power, at various retarded injection timings and higher injection pressures. Reduced ignition delay, improved combustion, and simultaneous reduction in oxides of nitrogen and smoke emissions with modest deterioration in performance are observed when the engine is operated at 500 bar injection pressure and at an injection timing of 16° before the top dead centre.

World Journal of Engineering

Purpose This study aims to find a new alternate source for biodiesel conversion. The alternate so... more Purpose This study aims to find a new alternate source for biodiesel conversion. The alternate source must be easily available, and it should give more oil yield than available edible, inedible sources. To meet the fuel demand in the transportation sector with edible oil-based biodiesel causes food versus fuel crisis. In addition to this, it increases NOx and CO2 in the environment. Design/methodology/approach The present paper reviews the comparison of algae oil yield, fatty acid composition and its biodiesel properties’ effect on diesel engine characteristics. Findings Algae were the only source to fulfil fuel demand because its oil and biodiesel yield is higher than other sources. Algae can grow by capturing carbon dioxide from the environment, and its fatty acid composition is more suitable to run diesel engines. Originality/value There is an improvement in engine performance–emission tradeoff with algal biodiesel.

Renewable and Sustainable Energy Reviews

Existing fossil fuels may not be able to meet the energy demand in near future due to rapid incre... more Existing fossil fuels may not be able to meet the energy demand in near future due to rapid increase in oil consumption. Fluctuating oil prices, depleting oil reserves and high level of harmful emissions through the use of conventional diesel forced the research community to focus their attention on the use of biofuels in compression ignition (CI) engines. Extensive use of biofuels offer multitude of advantages such as social structure, self-sustainability, soil development, effective use of cultivable land and self-employment. Butanol and pentanol are the most attractive biofuels, which could relieve energy crisis and reduce carcinogenic particulate matter (PM) emissions that are customary in CI engines. Research in the recent past has witnessed the notable amount of study in the use of these alcohols, mainly because of the improved yield through modern fermentation processes. Present work reviews the literature on the effects of using butanol and pentanol on the combustion, performance and exhaust emissions of CI engines operating under various test conditions. Attention is paid towards the review of strategies employed for use of higher alcohols in neat or in blended form to increase the renewable fraction of fuels in CI engines. The combination of exhaust gas recirculation (EGR) rates, delayed injection and the use of higher alcohols can enable low temperature combustion (LTC) strategy in CI engines, which presents simultaneous reduction in oxides of nitrogen (NOx) and soot emissions with increased efficiency. This paper also summarizes the key findings of earlier researchers contributed for use of biofuels in CI engines emphasizing higher alcohols. These biofuels are potential and attractive alternatives for the use in CI engines for improved performance and substantial reduction of harmful emissions.

Alexandria Engineering Journal, 2017

Abstract Diesel fueled CI engine is a widely accepted prime over owing to its high fuel conversio... more Abstract Diesel fueled CI engine is a widely accepted prime over owing to its high fuel conversion efficiency and load bearing capabilities. However, its use is constrained by high NOx and PM emissions. To address the issue of effective abatement of these emissions, an attempt is made in the present work and work reports numerical studies on the effect of reformed exhaust gas recirculation (REGR) of a single cylinder compression ignition engine fueled with diesel. For this purpose, a computational study using ECFM-3Z (extended coherent flame model-3 zones) model, ES-ICE and STAR-CD code has been carried out. Considering a sector model of an engine cylinder, in-cylinder pressures and temperatures Soot and Nitrous oxides (NOX) emission characteristics are observed. The studies include numerical experiments on various levels of REGR with two different compositions and comparison with their respective exhaust gas recirculation (EGR) levels at medium load conditions (write specific amounts). The REGR trends of combustion and emissions are significantly modified (is it correct here) when compared to EGR levels. Peak pressures for all REGR cases are higher than those for corresponding EGR levels. A maximum of 12.1% increase in peak pressure is found for 15% REGR (25%H2-0%CO) case than that for 15% EGR. Except for 25% REGR cases, Piston work for 5% REGR and 15% REGR cases is found to be higher than that for respective EGR because of H2 combustion dominance over exhaust gases dilution. Soot emissions for all REGR cases are observed lower than those for corresponding EGR cases. A maximum reduction of 12.73% is noted for 15% REGR (25%H2-0%CO) case than that for 15% EGR.

Volume 8A: Heat Transfer and Thermal Engineering, 2014

HCCI combustion is gaining increased attention amongst the research community to make it viable i... more HCCI combustion is gaining increased attention amongst the research community to make it viable in both diesel and gasoline engines. Of late, technique of External mixture formation is being adopted to avoid the problems associated with the early injection and late injections of the direct injected diesel HCCI engine. This paper reports the numerical studies on the effect of External mixture formation using three-zone extended coherent flame (ECFM-3Z) CFD model of the STAR - CD package. Firstly, the results obtained through package were validated with the results available in the literature. Trade-off between HC, CO and NOx was clearly observed through simulation. The simulation results revealed decrease in in-cylinder pressures and NOx emissions with increase in EGR concentration. There is an under prediction of NOx emissions when compared with the experimental results. However, a significant reduction in NOx emissions was observed with external mixture formation, usage compared to direct diesel injection. In case of HC and CO emissions increasing trend was observed with increase in EGR concentration. Increase in HC and CO emissions was observed with external mixture formation when compared with a direct diesel injection. Also, reduction in turbulent kinetic energy and velocity magnitude levels were observed with increase in EGR concentration. Improved piston work is resulted at lower EGR concentrations. Studies revealed that for a given combustion bowl geometry, It is concluded that external mixture formation technique could be adopted to achieve HCCI combustion.Copyright © 2014 by ASME

Frontiers in Energy, 2016

The major advantages of homogeneous charge compression ignition (HCCI) are high efficiency in com... more The major advantages of homogeneous charge compression ignition (HCCI) are high efficiency in combination with low NO x -emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR–CD is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM- 3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation (EGR) and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EGR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.

Trends in Mechanical Engineering Technology, Aug 4, 2015

Riveted joints are widely used for fastening sheet metal components. Cylindrical rivets are gener... more Riveted joints are widely used for fastening sheet metal components. Cylindrical rivets are generally preferred but due to space constraints in some cases, other geometries are being explored. In this work, a practical case of a rectangular riveted assembly for back plate of pendulum absorber assembly commonly used in modern vehicles for damping secondary vibrations is considered and an iterative simulation study for design optimization has been conducted using finite element based software FORGE for the riveting process. Efficacy of riveted joints is analyzed in terms of Von-Mises stresses, tonnage and contact pressure. Out of the many design parameters, only prominent parameters like variation of fillet radius in the plate hole and rivet and the distance between the hole and the side of the plate were concentrated upon. An attempt is made to change the values of these design parameters to arrive at an optimum design criterion for the riveted joint so that the stress induced is minimized to a value that can be considered to be within permissible limits. It is found out by iterative simulation studies that the maximum stress induced got reduced by 23.2% with a square rivet as compared to a rectangular rivet. Keywords: Rectangular riveted assembly, FE software FORGE, design parameters, simulation studies Cite this Article Ratnadeep Bhattacharjee, Madhu Murthy K, Amba Prasad Rao G. Design Optimization of a Riveted Joint Used in Back Plate of a Pendulum Absorber Assembly. Trends in Mechanical Engineering & Technology. 2015; 5(1): 36–50p.

Archives of Computational Methods in Engineering, 2016

Ranque–Hilsch vortex tube is a simple devise with no moving parts which could generate cold and h... more Ranque–Hilsch vortex tube is a simple devise with no moving parts which could generate cold and hot air/gas streams simultaneously with compressed air/gas as a working fluid. The energy and flow separation in a vortex tube is highly depends on factors like nozzle shape, nozzle number, diameter and length of the vortex tube, inlet pressure, control valve, diaphragm hole size and cold mass fraction. As the energy separation and flow patterns in a vortex tube are highly complex and were not explained successfully by any researcher, a computational study of vortex tube flow and energy separation will give a better understanding about the physics and mechanism involved. Many researchers conducted computational fluid dynamic analysis of the vortex to have a deep insight about the process of flow separation. In this paper computational analysis of vortex by many researchers were presented along with the results obtained and suggestions to improve the performance of the vortex tube. Researchers considered Turbulence models which predict the performance precisely were discussed in the present paper. Researchers considered turbulence models like LES, k–ε, k–ω and RMS to predict the energy separation in vortex tube. Some researchers considered artificial neural networks (ANN) and Taguchi methods for their analysis. Comparison of the predictions with simulation results were also presented to give a clear idea for the reader about the CFD models prediction capabilities.

Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2015

Compression ignitions with diesel fuel find wide applications ranging from light duty to heavy du... more Compression ignitions with diesel fuel find wide applications ranging from light duty to heavy duty. Diesel engines exhibit higher fuel conversion efficiency when compared to its counterpart-spark ignited engines. However, diesels pose the challenges of high NOx and soot emissions. Pollution-related issues are hampering the engine development processes. Experimental studies demand expensive hardware and researchers are resorting to computational investigation in optimizing engine performance parameters. Exhaust gas recirculation has been widely adopted to lower NOx emissions. Of late, split or multiple-injection strategy has been explored by many to precisely control the fuel injected per cycle and also to mitigate emissions. The present paper deals with the development of a single-zone phenomenological model for the combustion process for both in conventional and in a split injection diesel engine. The model considers a numerical solution of the energy equation while considering the effects of heat loss and temporally varying mixture-averaged values of gas constant. Pre-injection and main injection were modelled using physics-based models for fuel injection, ignition delay, premixed and diffusion heat release rates. The present study also emphasizes on pollutant formation of diesel engine under different operating conditions such as fuel injection timings, ambient conditions and EGR. EGR levels have been varied from 0 to 20 % where as two different multiple-injection levels are incorporated to examine the efficacy of the techniques adopted. It is observed that very low NOx levels are achieved with 20 % EGR with deterioration in engine performance, whereas with split injection NOx levels could be reduced without much loss in engine performance. The present analysis realized in a trade-off between NOx emissions and piston work. It is concluded that engine with split-injection strategy incorporated with electronic controls could be a better option for mitigating harmful engine emissions.

Heat Transfer [Working Title]

Microchannel flow is an effective solution for many engineering problems. Application of microcha... more Microchannel flow is an effective solution for many engineering problems. Application of microchannels is found in various fields such as thermal management of electronics, micro-combustors, biomedical industries, MEMS. In microchannel flow, some internal and external influences such as surface roughness, electric and magnetic fields are very significant and commonly neglected in macro-scale flow. Early research works on microchannels stated that the conventional theories of macro-scale flow were not applicable for microscale flows. Finally, researchers are concluded that the deviation in conventional theories in the case of micro-scale flow is because of neglecting the internal forces, surface roughness, surface wettability, etc., which play a prime role in micro-scale flows. In this chapter, the behavior of microchannel flow under the internal and external influences is discussed. The heat transfer and hydrodynamic characteristics of microchannel flow under the external magnetic f...

Heat Transfer - Design, Experimentation and Applications, 2021

Thermal management of electronic equipment is the primary concern in the electronic industry. Min... more Thermal management of electronic equipment is the primary concern in the electronic industry. Miniaturization and high power density of modern electronic components in the energy systems and electronic devices with high power density demanded compact heat exchangers with large heat dissipating capacity. Microchannel heat sinks (MCHS) are the most suitable heat exchanging devices for electronic cooling applications with high compactness. The heat transfer enhancement of the microchannel heat sinks (MCHS) is the most focused research area. Huge research has been done on the thermal and hydraulic performance enhancement of the microchannel heat sinks. This chapter’s focus is on advanced heat transfer enhancement methods used in the recent studies for the MCHS. The present chapter gives information about the performance enhancement MCHS with geometry modifications, Jet impingement, Phase changing materials (PCM), Nanofluids as a working fluid, Flow boiling, slug flow, and magneto-hydrod...

Heat Transfer Engineering, 2019

In this article, a three-time level finite difference scheme is used to resolve the dual phase la... more In this article, a three-time level finite difference scheme is used to resolve the dual phase lag's (DPL) heat conduction in a micro scale gold film subjected to spontaneous temperature boundary conditions without knowing the heat flux. Finite difference analog of DPL equation on applying to the intermediate grid points of the computational domain results into a system of linear, algebraic equations which can be solved using Thomas' algorithm to finally obtain the transient temperature solution distributions in the film. The solution predicted by the DPL model is compared with that obtained by the single-phase Cattaneo-Vernotte's model. Further, the way in which non-Fourier's temperature distributions affected by the diffusion due to the increase in Heat Conduction Model numbers agree with the predecessor's published results. The results by both the models revealed a finite thermal wave speed in the film contrasting the infinite speed of heat propagation as stated by the classical Fourier's thermal model. Low spatial step and higher order finite difference schemes are recommended for better accurate numerical results of the non-Fourier's temperature distributions occurring in the very short transient period between the instants of the suddenly applied spatial temperature gradient and the reaching of the steady state conditions.

Energy, Environment, and Sustainability, 2021

The engine block is a crucial component of internal combustion engines since it provides the sour... more The engine block is a crucial component of internal combustion engines since it provides the source of power for the vehicle. The engine block is a solid cast element that contains the cylinders and their related components inside a cooled and lubricated crankcase. The majority of engine blocks are cast iron, a brittle rich material that can sustain greater variations and weights while also being vibration resistant. Energy is changed from potential chemical energy to mechanical energy in this step, which is heat produced from burning fuel in the form of mechanical energy. A large amount of energy may be lost during the firing of an engine. This must be assessed using CFD prediction techniques. For starters, significant thermal and structural stresses may be produced over the cylinder blocks and pistons. Prior to the fabrication of the specific Internal Combustion engine, the structural and thermal analysis aids in the failure analysis. The solid modeller Parametric-Creo is used to create the current and new engine block models. This technical chapter will cover the simulation and analysis of the structural and thermal consequences of each specified bore piston and cylinder block model. The effective stress and temperature analysis using the finite element method will be performed using current tools such as ANSYS workbench, ADSL, and Deform 3D, with the processes and analytical functions described utilising supplementary literature theories, which can be found here.

A zero dimensional model has been used to investigate the combustion performance of a single cyli... more A zero dimensional model has been used to investigate the combustion performance of a single cylinder direct injection diesel engine fueled by biofuels with options like supercharging and exhaust gas recirculation. The numerical simulation was performed at constant speed. The indicated pressure, temperature diagrams are plotted and compared for different fuels. The emissions of soot and nitrous oxide are computed with phenomenological models. The experimental work was also carried out with biodiesel (palm stearin methyl ester) diesel blends, ethanol diesel blends to validate simulation results with experimental results, and observed that the present model is successful in predicting the engine performance with biofuels.

Journal of Energy Resources Technology

The typical tradeoff between the two major emissions from compression ignition (CI) engines, smok... more The typical tradeoff between the two major emissions from compression ignition (CI) engines, smoke and oxides of nitrogen, is the unresolved challenge to the researchers. Techniques like engine downsizing, lowering intake oxygen concentration, multiple injections, use of retarded injection timings and higher injection pressures, etc. are widely employed for the alleviation of these harmful emissions. The influence of variation of fuel injection pressure (FIP), boost pressure, pilot injection timing (PIT), pilot injection quantity (PIQ) and main injection timing (MIT) are experimentally investigated in the present work. Mahindra mHawk four-cylinder diesel engine with provisions of a variable-geometry turbocharger (VGT), exhaust gas recirculation (EGR), and common-rail direct injection (CRDi) is chosen for the experimentation. Test runs are conducted at 1750 rpm and 80.3 N.m (4.6 bar bmep) corresponding to highway drive conditions, using 10 % EGR. Response surface methodology is emplo...

International Journal of Ambient Energy

Biodiesel from non-edible oil sources can be a promising solution to meet the ever-increasing fue... more Biodiesel from non-edible oil sources can be a promising solution to meet the ever-increasing fuel crisis and environmental degradation. Sterculia foetida is one of the less exploited biodiesel fee...

International Journal of Energy Technology

Day to day increasing vehicles usage for human activities is caused to accumulate greenhouse emis... more Day to day increasing vehicles usage for human activities is caused to accumulate greenhouse emissions into the environment. The biodiesel is a best alternative fuel to run diesel engines. But its lower Calorific value and higher NOx emissions makes the consumer should compromise with engine performance and emission characteristics. As we know, that the use of additives to improve engine Combustion and emissions are caused to increase the fuel cost due to the higher cost of additives. The biodiesel conversion process of third generation biodiesel is costlier and required technological advancements for qualitative fuel. In the present work, the author used mixed culture micro algal particles in Coconut biodiesel (CCNME+AP) to improve engine characteristics. The Brake Thermal Efficiency (BTE) was enhanced, and the NOx emissions were less due to the absorption of heat in the Combustion chamber, it led to cool combustion phenomena with the Algal particles contained Coconut Biodiesel (CC...

Proceedings of the National Academy of Sciences, India Section A: Physical Sciences

The day-to-day human needs are strongly associated with the transportation and industrial sectors... more The day-to-day human needs are strongly associated with the transportation and industrial sectors, which are influencing to deplete fossil fuel reserves. At this situation, the use of biodiesel in an efficient way is the only practical alternative to run compression ignition engines. The biodiesels fuel-borne oxygen may reduce carbon monoxide (CO), unburnt hydrocarbons (HC), and smoke emissions but increase carbon dioxide (CO 2 ) and oxides of nitrogen (NO x ) emissions. The scientists and researchers are starving to improve engine performance by reducing the most harmful NO x emissions. Because of this, the author has investigated naturally aspirated single-cylinder unmodified direct injection compression ignition (DICI) engine. Two grams of mixed culture algal biomass particles are added in highly saturated coconut and unsaturated Karanja biodiesel fuels. The brake thermal efficiency of algal particles-emulsified fuels increased due to the explosion of biodiesel-surrounded algal particles after attaining autoignition temperature. The reduction in NO x emissions is noticed with algal particles-emulsified fuels because the particles absorb heat from the combustion chamber.

Proceeding of Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)

International Journal of Ambient Energy

ABSTRACT Improved engine exhaust emissions with little or no deterioration in performance may be ... more ABSTRACT Improved engine exhaust emissions with little or no deterioration in performance may be achieved through the use of new technologies and/or modifying the engine hardware. Present paper details the attempts of an experimental evaluation of Kirloskar make TV1 type diesel engine equipped with common rail direct injection (CRDi) and electronic control unit (ECU). It is established that retarded injection timing and smaller fuel droplets simultaneously reduce NO x and smoke emissions of a typical diesel engine. Hence engine testing was carried out using diesel fuel at 1500 rpm, under 50–100% of full load brake power, at various retarded injection timings and higher injection pressures. Reduced ignition delay, improved combustion, and simultaneous reduction in oxides of nitrogen and smoke emissions with modest deterioration in performance are observed when the engine is operated at 500 bar injection pressure and at an injection timing of 16° before the top dead centre.

World Journal of Engineering

Purpose This study aims to find a new alternate source for biodiesel conversion. The alternate so... more Purpose This study aims to find a new alternate source for biodiesel conversion. The alternate source must be easily available, and it should give more oil yield than available edible, inedible sources. To meet the fuel demand in the transportation sector with edible oil-based biodiesel causes food versus fuel crisis. In addition to this, it increases NOx and CO2 in the environment. Design/methodology/approach The present paper reviews the comparison of algae oil yield, fatty acid composition and its biodiesel properties’ effect on diesel engine characteristics. Findings Algae were the only source to fulfil fuel demand because its oil and biodiesel yield is higher than other sources. Algae can grow by capturing carbon dioxide from the environment, and its fatty acid composition is more suitable to run diesel engines. Originality/value There is an improvement in engine performance–emission tradeoff with algal biodiesel.

Renewable and Sustainable Energy Reviews

Existing fossil fuels may not be able to meet the energy demand in near future due to rapid incre... more Existing fossil fuels may not be able to meet the energy demand in near future due to rapid increase in oil consumption. Fluctuating oil prices, depleting oil reserves and high level of harmful emissions through the use of conventional diesel forced the research community to focus their attention on the use of biofuels in compression ignition (CI) engines. Extensive use of biofuels offer multitude of advantages such as social structure, self-sustainability, soil development, effective use of cultivable land and self-employment. Butanol and pentanol are the most attractive biofuels, which could relieve energy crisis and reduce carcinogenic particulate matter (PM) emissions that are customary in CI engines. Research in the recent past has witnessed the notable amount of study in the use of these alcohols, mainly because of the improved yield through modern fermentation processes. Present work reviews the literature on the effects of using butanol and pentanol on the combustion, performance and exhaust emissions of CI engines operating under various test conditions. Attention is paid towards the review of strategies employed for use of higher alcohols in neat or in blended form to increase the renewable fraction of fuels in CI engines. The combination of exhaust gas recirculation (EGR) rates, delayed injection and the use of higher alcohols can enable low temperature combustion (LTC) strategy in CI engines, which presents simultaneous reduction in oxides of nitrogen (NOx) and soot emissions with increased efficiency. This paper also summarizes the key findings of earlier researchers contributed for use of biofuels in CI engines emphasizing higher alcohols. These biofuels are potential and attractive alternatives for the use in CI engines for improved performance and substantial reduction of harmful emissions.

Alexandria Engineering Journal, 2017

Abstract Diesel fueled CI engine is a widely accepted prime over owing to its high fuel conversio... more Abstract Diesel fueled CI engine is a widely accepted prime over owing to its high fuel conversion efficiency and load bearing capabilities. However, its use is constrained by high NOx and PM emissions. To address the issue of effective abatement of these emissions, an attempt is made in the present work and work reports numerical studies on the effect of reformed exhaust gas recirculation (REGR) of a single cylinder compression ignition engine fueled with diesel. For this purpose, a computational study using ECFM-3Z (extended coherent flame model-3 zones) model, ES-ICE and STAR-CD code has been carried out. Considering a sector model of an engine cylinder, in-cylinder pressures and temperatures Soot and Nitrous oxides (NOX) emission characteristics are observed. The studies include numerical experiments on various levels of REGR with two different compositions and comparison with their respective exhaust gas recirculation (EGR) levels at medium load conditions (write specific amounts). The REGR trends of combustion and emissions are significantly modified (is it correct here) when compared to EGR levels. Peak pressures for all REGR cases are higher than those for corresponding EGR levels. A maximum of 12.1% increase in peak pressure is found for 15% REGR (25%H2-0%CO) case than that for 15% EGR. Except for 25% REGR cases, Piston work for 5% REGR and 15% REGR cases is found to be higher than that for respective EGR because of H2 combustion dominance over exhaust gases dilution. Soot emissions for all REGR cases are observed lower than those for corresponding EGR cases. A maximum reduction of 12.73% is noted for 15% REGR (25%H2-0%CO) case than that for 15% EGR.

Volume 8A: Heat Transfer and Thermal Engineering, 2014

HCCI combustion is gaining increased attention amongst the research community to make it viable i... more HCCI combustion is gaining increased attention amongst the research community to make it viable in both diesel and gasoline engines. Of late, technique of External mixture formation is being adopted to avoid the problems associated with the early injection and late injections of the direct injected diesel HCCI engine. This paper reports the numerical studies on the effect of External mixture formation using three-zone extended coherent flame (ECFM-3Z) CFD model of the STAR - CD package. Firstly, the results obtained through package were validated with the results available in the literature. Trade-off between HC, CO and NOx was clearly observed through simulation. The simulation results revealed decrease in in-cylinder pressures and NOx emissions with increase in EGR concentration. There is an under prediction of NOx emissions when compared with the experimental results. However, a significant reduction in NOx emissions was observed with external mixture formation, usage compared to direct diesel injection. In case of HC and CO emissions increasing trend was observed with increase in EGR concentration. Increase in HC and CO emissions was observed with external mixture formation when compared with a direct diesel injection. Also, reduction in turbulent kinetic energy and velocity magnitude levels were observed with increase in EGR concentration. Improved piston work is resulted at lower EGR concentrations. Studies revealed that for a given combustion bowl geometry, It is concluded that external mixture formation technique could be adopted to achieve HCCI combustion.Copyright © 2014 by ASME

Frontiers in Energy, 2016

The major advantages of homogeneous charge compression ignition (HCCI) are high efficiency in com... more The major advantages of homogeneous charge compression ignition (HCCI) are high efficiency in combination with low NO x -emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR–CD is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM- 3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation (EGR) and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EGR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.

Trends in Mechanical Engineering Technology, Aug 4, 2015

Riveted joints are widely used for fastening sheet metal components. Cylindrical rivets are gener... more Riveted joints are widely used for fastening sheet metal components. Cylindrical rivets are generally preferred but due to space constraints in some cases, other geometries are being explored. In this work, a practical case of a rectangular riveted assembly for back plate of pendulum absorber assembly commonly used in modern vehicles for damping secondary vibrations is considered and an iterative simulation study for design optimization has been conducted using finite element based software FORGE for the riveting process. Efficacy of riveted joints is analyzed in terms of Von-Mises stresses, tonnage and contact pressure. Out of the many design parameters, only prominent parameters like variation of fillet radius in the plate hole and rivet and the distance between the hole and the side of the plate were concentrated upon. An attempt is made to change the values of these design parameters to arrive at an optimum design criterion for the riveted joint so that the stress induced is minimized to a value that can be considered to be within permissible limits. It is found out by iterative simulation studies that the maximum stress induced got reduced by 23.2% with a square rivet as compared to a rectangular rivet. Keywords: Rectangular riveted assembly, FE software FORGE, design parameters, simulation studies Cite this Article Ratnadeep Bhattacharjee, Madhu Murthy K, Amba Prasad Rao G. Design Optimization of a Riveted Joint Used in Back Plate of a Pendulum Absorber Assembly. Trends in Mechanical Engineering & Technology. 2015; 5(1): 36–50p.

Archives of Computational Methods in Engineering, 2016

Ranque–Hilsch vortex tube is a simple devise with no moving parts which could generate cold and h... more Ranque–Hilsch vortex tube is a simple devise with no moving parts which could generate cold and hot air/gas streams simultaneously with compressed air/gas as a working fluid. The energy and flow separation in a vortex tube is highly depends on factors like nozzle shape, nozzle number, diameter and length of the vortex tube, inlet pressure, control valve, diaphragm hole size and cold mass fraction. As the energy separation and flow patterns in a vortex tube are highly complex and were not explained successfully by any researcher, a computational study of vortex tube flow and energy separation will give a better understanding about the physics and mechanism involved. Many researchers conducted computational fluid dynamic analysis of the vortex to have a deep insight about the process of flow separation. In this paper computational analysis of vortex by many researchers were presented along with the results obtained and suggestions to improve the performance of the vortex tube. Researchers considered Turbulence models which predict the performance precisely were discussed in the present paper. Researchers considered turbulence models like LES, k–ε, k–ω and RMS to predict the energy separation in vortex tube. Some researchers considered artificial neural networks (ANN) and Taguchi methods for their analysis. Comparison of the predictions with simulation results were also presented to give a clear idea for the reader about the CFD models prediction capabilities.

Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2015

Compression ignitions with diesel fuel find wide applications ranging from light duty to heavy du... more Compression ignitions with diesel fuel find wide applications ranging from light duty to heavy duty. Diesel engines exhibit higher fuel conversion efficiency when compared to its counterpart-spark ignited engines. However, diesels pose the challenges of high NOx and soot emissions. Pollution-related issues are hampering the engine development processes. Experimental studies demand expensive hardware and researchers are resorting to computational investigation in optimizing engine performance parameters. Exhaust gas recirculation has been widely adopted to lower NOx emissions. Of late, split or multiple-injection strategy has been explored by many to precisely control the fuel injected per cycle and also to mitigate emissions. The present paper deals with the development of a single-zone phenomenological model for the combustion process for both in conventional and in a split injection diesel engine. The model considers a numerical solution of the energy equation while considering the effects of heat loss and temporally varying mixture-averaged values of gas constant. Pre-injection and main injection were modelled using physics-based models for fuel injection, ignition delay, premixed and diffusion heat release rates. The present study also emphasizes on pollutant formation of diesel engine under different operating conditions such as fuel injection timings, ambient conditions and EGR. EGR levels have been varied from 0 to 20 % where as two different multiple-injection levels are incorporated to examine the efficacy of the techniques adopted. It is observed that very low NOx levels are achieved with 20 % EGR with deterioration in engine performance, whereas with split injection NOx levels could be reduced without much loss in engine performance. The present analysis realized in a trade-off between NOx emissions and piston work. It is concluded that engine with split-injection strategy incorporated with electronic controls could be a better option for mitigating harmful engine emissions.