sabu kurian - Academia.edu (original) (raw)

Papers by sabu kurian

Journal of Applied Fluid Mechanics, Mar 1, 2022

The objective of this research is to numerically investigate heat transfer and pressure drop char... more The objective of this research is to numerically investigate heat transfer and pressure drop characteristic of a baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two baffle configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter D=5 mm and with jet-to-heated plate distance ranging from 2D to 3.5D were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio and baffle clearance on heat transfer and pressure drop characteristics. Blow ratios of 0.25, 0.5, 0.75 and 1.0 and baffle clearances of 1 mm, 2 mm, and 3mm were considered for CFD simulations. The split baffle configuration with baffle clearance of 3 mm is found to be more advantageous when both heat transfer and pressure drop are considered. However, the segmented baffle configuration with a baffle clearance of 1 mm gave better results for heat transfer alone. The present study also deals with determination of optimal operating parameters with the help of Genetic Algorithm and Artificial Neural Network. A pareto front was obtained for selecting the desired value of heat transfer or pressure drop. It was found that Artificial Neural Network based predictions strongly agree with CFD simulation results, and hence seems to be very useful in arriving at the optimum values of operating parameters.

IOP conference series, Apr 1, 2021

The objective of this research is to numerically investigate heat transfer characteristic of a lo... more The objective of this research is to numerically investigate heat transfer characteristic of a louvered baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two h/d configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter d=5 mm and with jet-to-target plate distance ranging from 2d to 3 d were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio, louver angle and baffle clearance on heat transfer. Blow ratios of 0.25, 0.5, 075 and 1.0 and louver angle 30°, 45° and 60° were considered for CFD simulations. In all the cases, heat transfer increases with blow ratio and blow ratio with 1 has the maximum heat transfer. It is also noticed that heat transfer rate increases with decrease in louver angle h/d ratio.

This study deals with the cumulative pitch variations in DIN male contacts. A connector provides ... more This study deals with the cumulative pitch variations in DIN male contacts. A connector provides a separable interface between two subsystems of an electronic system. DIN is a series of connector which stands for Deutsch Institut fur Normung. They are used for applications like switching, transmission, radio base stations, control units and machines. Connector manufacturing involves stamping, moulding, plating and assembly processes. Manufacturing of contacts is known as stamping. Stamped contacts are then plated and they are assembled to the moulded insulator to form a connector. The purpose of this study is to eliminate pitch variations occurring during the stamping of DIN contacts.

Materials Today: Proceedings, 2021

Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most effici... more Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most efficient heat transfer technologies for cooling applications. Detailed investigations are required to optimize the different parameters to achieve maximum heat transfer. Present study is an effort in this direction by analyzing the heat transfer from a flat heating film of dimension 60 × 60 × 0.1 mm. The chip generates a heat of 30 W which is to be carried away by means of air jets. The nozzle plate at the top generating the air jet has a set of 9 nozzles arranged in a 3x3 inline configuration. Two sides of the flow arrangement are confined and flow is only along one direction. The nozzle diameter is 5 mm and pitch length from center to center X/D and Y/D are 3. The nozzle plate, heating plate gap Z/D is 4. The Reynolds number values are in the range 3500 to 14000. The cross-flow approaches in a direction perpendicular to the jets and mixes with the jet flow. The results obtained predict a dominance of pulsed jets over steady jets, if heat transfer is considered. Among pulsed jets, those with higher amplitudes and lower frequencies showcase better heat transfer and more uniform distribution throughout the heated plate.

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2021

Use of baffles in jet impingement systems in presence of initial cross-flow disturbs boundary lay... more Use of baffles in jet impingement systems in presence of initial cross-flow disturbs boundary layer that results in rise in heat transfer. Two configurations of baffle assisted impingement systems were considered and a comparative study on heat transfer and pressure drop is carried out based on operating parameters such as baffle clearance, blow ratio and h/D ratio using commercially available CFD package. Numerical predictions showed that both heat transfer and pressure drop in segmented configuration were higher than louvered configuration for all blow ratio employed in this study. Parametric studies showed that, thermo-hydraulic performance parameter is higher only for louvered configurations at low blow ratio. When cross-flow velocity is comparable with jet velocity, segmented baffles resulted in relatively higher thermo-hydraulic performance because of its higher heat transfer rate relative to the incurring pressure drop. An increase in clearance proportionally increases perfor...

The advancement in science had led to highly complicated electronic devices and at the same time ... more The advancement in science had led to highly complicated electronic devices and at the same time the size of such devices is getting reduced day by day. The amount of heat generated by these devices is increasing in par with its complexity. The efficiency of electronics devices decreases with increase in temperature. The cooling of these devices to their normal working temperature is a great challenge since the area available for heat transfer will be very less and there is restricted movement of air. This paper deals with jet impingement cooling, in which high velocity jets are used for removal of heat from a surface. The jets are arranged in the form of a staggered array and are pulsating in nature. To increase the turbulence in the flow domain the jets are pulsated at a phase shift. The study is carried out at different frequencies. The objective of this study is to compare the heat transfer at different combinations of frequencies and angles of phase shift and find the combinati...

Jet impingement systems provide an effective and simple means for the enhancement of convective p... more Jet impingement systems provide an effective and simple means for the enhancement of convective processes due to the high heat and mass transfer rates that can be achieved. The range of industrial applications that impinging jets are being used in today is wide. A number of researchers have studied the forced convection heat transfer from jet arrays. This review paper gives various experimental and numerical approaches on jet impingement heat transfer process. In the course of the review, the flow and heat transfer characteristics of multiple impinging jets are introduced. Influencing factors on heat transfer are discussed, which include the effects of cross flow, jet Reynolds number, jet pattern, separation distance between a jet and target plate, and of the open area. In the review of numerical works, the suitability of the turbulent models in predicting local heat transfer rates for multi-jet systems is discussed.

Cooling of heated plates finds applications in various fields like electronic devices, gas turbin... more Cooling of heated plates finds applications in various fields like electronic devices, gas turbines, aerospace, textiles etc. Commonly used method for cooling of electronic devices such as computers is by using fan. With the advent of electronic industry cooling requirements from compact surfaces become the primary focus and jet impingement become one of the best methods for heat transfer. Numerous researchers has been done this field and is been going . The review studies different jet impingement cases having different geometry, cross flow, frequency effects etc.

In the present work the study on machining of 6061-T6 Aluminium alloys using diamond coated and u... more In the present work the study on machining of 6061-T6 Aluminium alloys using diamond coated and uncoated tungsten carbide end mills under dry conditions is conducted. This alloy has wide range of applications in the automotive and many other industries. For the above study, the diamond coating of the tools was performed using CVD process. The performance of the diamond coated tools has been compared with that of an uncoated tool and the results are presented and analyzed in this work.

AISI 420 stainless steel is a martensitic stainless steel which has good corrosion and magnetic p... more AISI 420 stainless steel is a martensitic stainless steel which has good corrosion and magnetic properties. It is used widely in rotors of actuator motors due to its magnetic property. Surface Roughness is one of the prominent factors that need to be optimised in this high precision work. The present work is aimed at characterizing the electric discharge machining of AISI 420 stainless steel. Taguchi’s L9 orthogonal array was chosen to conduct the experiments by varying EDM parameters like current, pulse on time and pulse off time. The surface roughness and Material removal rate are taken as the output responses. Signal to noise ratio and ANOVA is used to analyze the effect of parameters on surface roughness and also to identify the optimum machining parameters. Keywords— Orthogonal array, Electric discharge machining, Surface roughness, Material removal rate.

International Journal of Energy Technology and Policy, 2021

International Journal of Energy Technology and Policy, 2021

Materials Today: Proceedings, 2021

Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most effici... more Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most efficient heat transfer technologies for cooling applications. Detailed investigations are required to optimize the different parameters to achieve maximum heat transfer. Present study is an effort in this direction by analyzing the heat transfer from a flat heating film of dimension 60 × 60 × 0.1 mm. The chip generates a heat of 30 W which is to be carried away by means of air jets. The nozzle plate at the top generating the air jet has a set of 9 nozzles arranged in a 3x3 inline configuration. Two sides of the flow arrangement are confined and flow is only along one direction. The nozzle diameter is 5 mm and pitch length from center to center X/D and Y/D are 3. The nozzle plate, heating plate gap Z/D is 4. The Reynolds number values are in the range 3500 to 14000. The cross-flow approaches in a direction perpendicular to the jets and mixes with the jet flow. The results obtained predict a dominance of pulsed jets over steady jets, if heat transfer is considered. Among pulsed jets, those with higher amplitudes and lower frequencies showcase better heat transfer and more uniform distribution throughout the heated plate.

International Journal of Information and Decision Sciences, 2015

This paper proposes a modified serial scheduling scheme for resource constrained project scheduli... more This paper proposes a modified serial scheduling scheme for resource constrained project scheduling weighted earliness tardiness problem (RCPSPWET). Project activities are assumed to have known unit earliness and tardiness penalty cost and constant renewable resource requirements. The objective is to schedule the activities in such a way that it minimises the total weighted earliness-tardiness penalty cost of the project, subject to the precedence constraints and the constant renewable resource availability constraints. A modified serial scheduling scheme using a sliding factor is proposed along with a heuristic method for solving the RCPSPWET.

IOP Conference Series: Materials Science and Engineering, 2021

The objective of this research is to numerically investigate heat transfer characteristic of a lo... more The objective of this research is to numerically investigate heat transfer characteristic of a louvered baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two h/d configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter d=5 mm and with jet-to-target plate distance ranging from 2d to 3 d were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio, louver angle and baffle clearance on heat transfer. Blow ratios of 0.25, 0.5, 075 and 1.0 and louver angle 30°, 45° and 60° were considered for CFD simulations. In all the cases, heat transfer increases with blow ratio and blow ratio with 1 has the maximum heat transfer. It is also noticed that heat transfer rate increases with decrease in louver angle h/d ratio.

Cooling of heated plates finds applications in various fields like cooling of electronic devices.... more Cooling of heated plates finds applications in various fields like cooling of electronic devices. Commonly used method for cooling of electronic devices such as computers is by using fan. With the advent of electronic industry cooling requirements from compact surfaces become the primary focus of research. Jet impingement cooling mechanism with pulsating impinging jet array has proved to be one of the most efficient heat transfer mechanism for cooling applications. The idea of impingement heat transfer is to obtain the higher heat transfer coefficients from a given surface with limited area by means of the high velocity of the jets. Thus, a study is required to optimize the different aspects of the mechanism so as to achieve maximum heat transfer. In this project combined steady and pulsating jet array is used for heat transfer. Various arrangements of jets are considered. Also analysis of different frequencies of jets is done. The best combination for maximum and uniform heat trans...

This study deals with the cumulative pitch variations in DIN male contacts. A connector provides ... more This study deals with the cumulative pitch variations in DIN male contacts. A connector provides a separable interface between two subsystems of an electronic system. DIN is a series of connector which stands for Deutsch Institut fur Normung. They are used for applications like switching, transmission, radio base stations, control units and machines. Connector manufacturing involves stamping, moulding, plating and assembly processes. Manufacturing of contacts is known as stamping. Stamped contacts are then plated and they are assembled to the moulded insulator to form a connector. The purpose of this study is to eliminate pitch variations occurring during the stamping of DIN contacts. Keywords— DIN connector, Stamping, Pareto chart, Cause and effect diagram.

Journal of Applied Fluid Mechanics, Mar 1, 2022

The objective of this research is to numerically investigate heat transfer and pressure drop char... more The objective of this research is to numerically investigate heat transfer and pressure drop characteristic of a baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two baffle configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter D=5 mm and with jet-to-heated plate distance ranging from 2D to 3.5D were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio and baffle clearance on heat transfer and pressure drop characteristics. Blow ratios of 0.25, 0.5, 0.75 and 1.0 and baffle clearances of 1 mm, 2 mm, and 3mm were considered for CFD simulations. The split baffle configuration with baffle clearance of 3 mm is found to be more advantageous when both heat transfer and pressure drop are considered. However, the segmented baffle configuration with a baffle clearance of 1 mm gave better results for heat transfer alone. The present study also deals with determination of optimal operating parameters with the help of Genetic Algorithm and Artificial Neural Network. A pareto front was obtained for selecting the desired value of heat transfer or pressure drop. It was found that Artificial Neural Network based predictions strongly agree with CFD simulation results, and hence seems to be very useful in arriving at the optimum values of operating parameters.

IOP conference series, Apr 1, 2021

The objective of this research is to numerically investigate heat transfer characteristic of a lo... more The objective of this research is to numerically investigate heat transfer characteristic of a louvered baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two h/d configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter d=5 mm and with jet-to-target plate distance ranging from 2d to 3 d were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio, louver angle and baffle clearance on heat transfer. Blow ratios of 0.25, 0.5, 075 and 1.0 and louver angle 30°, 45° and 60° were considered for CFD simulations. In all the cases, heat transfer increases with blow ratio and blow ratio with 1 has the maximum heat transfer. It is also noticed that heat transfer rate increases with decrease in louver angle h/d ratio.

This study deals with the cumulative pitch variations in DIN male contacts. A connector provides ... more This study deals with the cumulative pitch variations in DIN male contacts. A connector provides a separable interface between two subsystems of an electronic system. DIN is a series of connector which stands for Deutsch Institut fur Normung. They are used for applications like switching, transmission, radio base stations, control units and machines. Connector manufacturing involves stamping, moulding, plating and assembly processes. Manufacturing of contacts is known as stamping. Stamped contacts are then plated and they are assembled to the moulded insulator to form a connector. The purpose of this study is to eliminate pitch variations occurring during the stamping of DIN contacts.

Materials Today: Proceedings, 2021

Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most effici... more Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most efficient heat transfer technologies for cooling applications. Detailed investigations are required to optimize the different parameters to achieve maximum heat transfer. Present study is an effort in this direction by analyzing the heat transfer from a flat heating film of dimension 60 × 60 × 0.1 mm. The chip generates a heat of 30 W which is to be carried away by means of air jets. The nozzle plate at the top generating the air jet has a set of 9 nozzles arranged in a 3x3 inline configuration. Two sides of the flow arrangement are confined and flow is only along one direction. The nozzle diameter is 5 mm and pitch length from center to center X/D and Y/D are 3. The nozzle plate, heating plate gap Z/D is 4. The Reynolds number values are in the range 3500 to 14000. The cross-flow approaches in a direction perpendicular to the jets and mixes with the jet flow. The results obtained predict a dominance of pulsed jets over steady jets, if heat transfer is considered. Among pulsed jets, those with higher amplitudes and lower frequencies showcase better heat transfer and more uniform distribution throughout the heated plate.

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2021

Use of baffles in jet impingement systems in presence of initial cross-flow disturbs boundary lay... more Use of baffles in jet impingement systems in presence of initial cross-flow disturbs boundary layer that results in rise in heat transfer. Two configurations of baffle assisted impingement systems were considered and a comparative study on heat transfer and pressure drop is carried out based on operating parameters such as baffle clearance, blow ratio and h/D ratio using commercially available CFD package. Numerical predictions showed that both heat transfer and pressure drop in segmented configuration were higher than louvered configuration for all blow ratio employed in this study. Parametric studies showed that, thermo-hydraulic performance parameter is higher only for louvered configurations at low blow ratio. When cross-flow velocity is comparable with jet velocity, segmented baffles resulted in relatively higher thermo-hydraulic performance because of its higher heat transfer rate relative to the incurring pressure drop. An increase in clearance proportionally increases perfor...

The advancement in science had led to highly complicated electronic devices and at the same time ... more The advancement in science had led to highly complicated electronic devices and at the same time the size of such devices is getting reduced day by day. The amount of heat generated by these devices is increasing in par with its complexity. The efficiency of electronics devices decreases with increase in temperature. The cooling of these devices to their normal working temperature is a great challenge since the area available for heat transfer will be very less and there is restricted movement of air. This paper deals with jet impingement cooling, in which high velocity jets are used for removal of heat from a surface. The jets are arranged in the form of a staggered array and are pulsating in nature. To increase the turbulence in the flow domain the jets are pulsated at a phase shift. The study is carried out at different frequencies. The objective of this study is to compare the heat transfer at different combinations of frequencies and angles of phase shift and find the combinati...

Jet impingement systems provide an effective and simple means for the enhancement of convective p... more Jet impingement systems provide an effective and simple means for the enhancement of convective processes due to the high heat and mass transfer rates that can be achieved. The range of industrial applications that impinging jets are being used in today is wide. A number of researchers have studied the forced convection heat transfer from jet arrays. This review paper gives various experimental and numerical approaches on jet impingement heat transfer process. In the course of the review, the flow and heat transfer characteristics of multiple impinging jets are introduced. Influencing factors on heat transfer are discussed, which include the effects of cross flow, jet Reynolds number, jet pattern, separation distance between a jet and target plate, and of the open area. In the review of numerical works, the suitability of the turbulent models in predicting local heat transfer rates for multi-jet systems is discussed.

Cooling of heated plates finds applications in various fields like electronic devices, gas turbin... more Cooling of heated plates finds applications in various fields like electronic devices, gas turbines, aerospace, textiles etc. Commonly used method for cooling of electronic devices such as computers is by using fan. With the advent of electronic industry cooling requirements from compact surfaces become the primary focus and jet impingement become one of the best methods for heat transfer. Numerous researchers has been done this field and is been going . The review studies different jet impingement cases having different geometry, cross flow, frequency effects etc.

In the present work the study on machining of 6061-T6 Aluminium alloys using diamond coated and u... more In the present work the study on machining of 6061-T6 Aluminium alloys using diamond coated and uncoated tungsten carbide end mills under dry conditions is conducted. This alloy has wide range of applications in the automotive and many other industries. For the above study, the diamond coating of the tools was performed using CVD process. The performance of the diamond coated tools has been compared with that of an uncoated tool and the results are presented and analyzed in this work.

AISI 420 stainless steel is a martensitic stainless steel which has good corrosion and magnetic p... more AISI 420 stainless steel is a martensitic stainless steel which has good corrosion and magnetic properties. It is used widely in rotors of actuator motors due to its magnetic property. Surface Roughness is one of the prominent factors that need to be optimised in this high precision work. The present work is aimed at characterizing the electric discharge machining of AISI 420 stainless steel. Taguchi’s L9 orthogonal array was chosen to conduct the experiments by varying EDM parameters like current, pulse on time and pulse off time. The surface roughness and Material removal rate are taken as the output responses. Signal to noise ratio and ANOVA is used to analyze the effect of parameters on surface roughness and also to identify the optimum machining parameters. Keywords— Orthogonal array, Electric discharge machining, Surface roughness, Material removal rate.

International Journal of Energy Technology and Policy, 2021

International Journal of Energy Technology and Policy, 2021

Materials Today: Proceedings, 2021

Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most effici... more Abstract Jet impingement technique with pulsed jet arrays has proved to be one of the most efficient heat transfer technologies for cooling applications. Detailed investigations are required to optimize the different parameters to achieve maximum heat transfer. Present study is an effort in this direction by analyzing the heat transfer from a flat heating film of dimension 60 × 60 × 0.1 mm. The chip generates a heat of 30 W which is to be carried away by means of air jets. The nozzle plate at the top generating the air jet has a set of 9 nozzles arranged in a 3x3 inline configuration. Two sides of the flow arrangement are confined and flow is only along one direction. The nozzle diameter is 5 mm and pitch length from center to center X/D and Y/D are 3. The nozzle plate, heating plate gap Z/D is 4. The Reynolds number values are in the range 3500 to 14000. The cross-flow approaches in a direction perpendicular to the jets and mixes with the jet flow. The results obtained predict a dominance of pulsed jets over steady jets, if heat transfer is considered. Among pulsed jets, those with higher amplitudes and lower frequencies showcase better heat transfer and more uniform distribution throughout the heated plate.

International Journal of Information and Decision Sciences, 2015

This paper proposes a modified serial scheduling scheme for resource constrained project scheduli... more This paper proposes a modified serial scheduling scheme for resource constrained project scheduling weighted earliness tardiness problem (RCPSPWET). Project activities are assumed to have known unit earliness and tardiness penalty cost and constant renewable resource requirements. The objective is to schedule the activities in such a way that it minimises the total weighted earliness-tardiness penalty cost of the project, subject to the precedence constraints and the constant renewable resource availability constraints. A modified serial scheduling scheme using a sliding factor is proposed along with a heuristic method for solving the RCPSPWET.

IOP Conference Series: Materials Science and Engineering, 2021

The objective of this research is to numerically investigate heat transfer characteristic of a lo... more The objective of this research is to numerically investigate heat transfer characteristic of a louvered baffle assisted multi-jet impingement of air on a heated plate subjected to constant heat flux and cross flow. Two h/d configurations were considered for the present study. An array of jets with 3 x 3 configurations discharging from round orifices of diameter d=5 mm and with jet-to-target plate distance ranging from 2d to 3 d were studied. SST k-ω turbulence model was used for numerical simulation to examine the effect of blow ratio, louver angle and baffle clearance on heat transfer. Blow ratios of 0.25, 0.5, 075 and 1.0 and louver angle 30°, 45° and 60° were considered for CFD simulations. In all the cases, heat transfer increases with blow ratio and blow ratio with 1 has the maximum heat transfer. It is also noticed that heat transfer rate increases with decrease in louver angle h/d ratio.

Cooling of heated plates finds applications in various fields like cooling of electronic devices.... more Cooling of heated plates finds applications in various fields like cooling of electronic devices. Commonly used method for cooling of electronic devices such as computers is by using fan. With the advent of electronic industry cooling requirements from compact surfaces become the primary focus of research. Jet impingement cooling mechanism with pulsating impinging jet array has proved to be one of the most efficient heat transfer mechanism for cooling applications. The idea of impingement heat transfer is to obtain the higher heat transfer coefficients from a given surface with limited area by means of the high velocity of the jets. Thus, a study is required to optimize the different aspects of the mechanism so as to achieve maximum heat transfer. In this project combined steady and pulsating jet array is used for heat transfer. Various arrangements of jets are considered. Also analysis of different frequencies of jets is done. The best combination for maximum and uniform heat trans...

This study deals with the cumulative pitch variations in DIN male contacts. A connector provides ... more This study deals with the cumulative pitch variations in DIN male contacts. A connector provides a separable interface between two subsystems of an electronic system. DIN is a series of connector which stands for Deutsch Institut fur Normung. They are used for applications like switching, transmission, radio base stations, control units and machines. Connector manufacturing involves stamping, moulding, plating and assembly processes. Manufacturing of contacts is known as stamping. Stamped contacts are then plated and they are assembled to the moulded insulator to form a connector. The purpose of this study is to eliminate pitch variations occurring during the stamping of DIN contacts. Keywords— DIN connector, Stamping, Pareto chart, Cause and effect diagram.