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In high speed flows nozzles are used to change pressure energy to kinetic energy which in turn is... more In high speed flows nozzles are used to change pressure energy to kinetic energy which in turn is used to produce thrust. In a converging-diverging nozzle, flow is augmented from subsonic to sonic velocity at the throat and further expanded to supersonic velocities at the exit. In this paper, an experimental study is performed to evaluate the supersonic flow in a CD nozzle with a suddenly expanded duct. At the base of the nozzle, the base pressure is controlled by employing tiny jets of 1 mm diameter with a circular crosssection having exit Mach number of as unity are arranged at ninety degrees at a PCD of 13 mm and 6.5 mm from the central jet axis. Obtained wall pressure distribution is shown for Mach number 2.8, and Axi-symmetric round brass duct was used to join micro-jets, an area ratio of that duct is 3.24. Tests were conducted for L/D from 10 to 1, and the level of expansion for tests considered for wall pressure data acquisition was from 3, 5, 7, 9 and 11. The results indicate that the flow field was not aggravated due to the deployment of the control.

In this experimental investigation the work reported is about the influence of control on the flo... more In this experimental investigation the work reported is about the influence of control on the flow field in the suddenly expanded duct at low supersonic Mach number. A Convergent-divergent (CD) nozzle was designed and fabricated out of brass material assembled with the suddenly expanded duct which was also made of brass material. At the re-circulation zone, the flow field was controlled by using the micro jets of 1 mm diameter as an orifice and the control was arranged at an interval of 90 degrees at 6.5 mm from the central axis of the main jet. The measured wall pressure distribution was presented for Mach number 1.1 for the duct diameter of 18 mm leading to the area ratio 3.24. The L/D ratio of the duct was varied from 1 to 10, and the nozzle pressure ratio (NPR) considered for the experiments was from 3, 5, 7, 9 and 11. The present results have demonstrated that the micro jets do not influence the flow field in the duct adversely and the flow field remained identical in the presence of control or absence of control.

The quick depletion of petroleum reserves rises in automobile emissions, and an increase in costs... more The quick depletion of petroleum reserves rises in automobile emissions, and an increase in costs and concerns for the environment has prompted a relentless quest to substitute fuels. For Gasoline, one of the best alternatives is found to be Ethyl Alcohol. As it is obtained from biomass crops enriched with starch, sugar, and cellulose material. These crops are renewable and pollution-free. The nature of ethyl alcohol is the same as compared to petrol. Both are liquid, and in this way, storage and transport are similar. Both can be blended expertly and burnt. In the present study, E30 (30% Ethanol + 70% Gasoline) blend was used and tests were carried out for a single-cylinder, 4stroke, computerized spark-ignition (SI) gasoline engine fitted with eddy current dynamometer. Further, a precisely adjusted exhaust gas analyzer and the performance, combustion, and emission characteristics of the Spark Ignition Engine were recorded in "Enginesoft" software. In order to reduce the problem of knocking in the Spark Ignition Engine, along with E30 Blend, Iso-Octane additive, which is an excellent anti-knocking agent, was added in 0.3%, 0.4% and 0.5% by volume, i.e., E30+0.3, E30+0.4 and E30+0.5 respectively.

In this study, an attempt is made to evaluate the effect of first arched ends on the damping deri... more In this study, an attempt is made to evaluate the effect of first arched ends on the damping derived due to the pitch rate aimed at the variable sine wave bounty, flow deflection angle δ, pivot position, and the Mach numbers. Results show that with the escalation in the bounty of the complete sine wave (i.e., positive amplitude) there is an enlightened escalation in the pitch damping derivatives from h = 0, later in the downstream in the route of the sprawling verge it decreases till the location of the center of pressure and vice versa. At the location where the reasonable force acts, when we consider the stability derivatives in damping for the rate of pitch q, there is a rise in the numerical tenets of the spinoffs. This increase is non-linear in nature and not like for position near the leading edges. The level of the stifling derivatives owing to variations in Mach numbers, flow bend approach δ, and generosity of the sine wave remained in the same range.

In this paper, a study on the effect of the control on the wall pressure as well as the quality o... more In this paper, a study on the effect of the control on the wall pressure as well as the quality of the flow when tiny jets were employed. The small jet aimed to regulate the base pressure at the base region of the suddenly expanded duct and wall pressure distribution is carried out experimentally. The convergent-divergent (CD) nozzle with a suddenly expanded duct was designed to observe the wall pressure distribution with and without control using small jets. In order to obtain the results with the effect of controlled four tiny jets of 1 mm diameter located at a ninety-degree interval along a pitch circle diameter (PCD) of 1.3 times the CD nozzle exit diameter in the base, region was employed as active controls. The Mach numbers of the rapidly expanded are 1.5. The jets were expanded quickly into an axis-symmetry duct with an area ratio of 4.84. The length-todiameter (L/D) ratio of the rapid expansion duct was diverse from 10 to 1. There is no adverse effect due to the presence of the tiny jets on the flow field as well as the quality of the flow in the duct.

This present study discusses the outcome of the experimental investigations, and the efficacy of ... more This present study discusses the outcome of the experimental investigations, and the efficacy of the tiny jets used to regulate the base pressure as well as the wall pressure in suddenly expanded flow. The control mechanism as tiny jets having a cross-section of 1 mm diameter was employed as the base pressure regulator at the exit periphery of the nozzle. The experiments were carried out to investigate and record the flow field at the rear end of the separated flow region for area ratio 4.84. Four tiny jets were placed at a distance of 6.5 mm away from the primary jet coming from the nozzle exit at ninety degrees apart, and the tiny control jets were flowing at sonic Mach number. The actual Mach number of the main jet was 1.1. The experimentation was accomplished at a different level of expansion (i. e., NPR = 3, 5, 7, 9, and 11) and the L/D ratio considered was from 10 to 1. This study mainly focuses on the development of the flow in the suddenly expanded duct, nature of the flow in the duct, and the impact of the Control on the wall pressure and the magnitude of the pressure along the duct. The wall pressure in the smooth duct is not unfavorably influenced by the control jets.

Miniaturization of gas turbines is not straightforward and is not simply the scaling down of larg... more Miniaturization of gas turbines is not straightforward and is not simply the scaling down of large gas turbines. The small dimensions have implications on the efficiency of the components due to the increased viscous friction. Also limits in fabrication accuracy cause additional flow losses. For a 120sec typical accel-decel mission, non-linear transient thermal & structural analyses were performed. It is important to note that this mission resembles true test conditions of gas turbine engines. An axisymmetric model was considered for analysis and mass approximations were carried out using real constants. Heat transfer coefficients are calculated using appropriate correlations and transient thermal scenario of system was captured. Structural analysis was performed at several time points in the mission cycle with all thermal & structural loads. Stress & temperature history of component was examined & fatigue life calculation was performed for all critical locations of the component. It is observed that component can run for a minimum 100000 cycles. Also, clearance calculation was performed for rotor & stator parts in system and observed that current method of assembly was safe. Regarding bearing design, at higher shaft speeds (up to 100000rpm); stainless steel ball bearings cannot withstand the stresses. So, ceramic ball bearings are used as the best feasible solution for the given temperature & pressures.

The need for transportation is increasing every day. Production of automobiles is catering to thi... more The need for transportation is increasing every day. Production of automobiles is catering to this need. The fuels used by these automobiles are mainly petrol and diesel. Discharge of pollutants present in these fuels causing air pollution. Renewable fuels with lesser emission and comparably cheaper are required as an alternative to reduce environmental pollution. Ethyl alcohol is having larger oxygen content, low molecular weight, and high H/C ratios and can burn completely with oxygen. The thermal efficiency of the spark-ignition engine can be improved, and the exhaust emissions can be reduced by using Ethyl alcohol. The objective of the study is to study experimentally, the performance, combustion, and emission characteristics were investigated with E25, E30 and E35 ethanol-gasoline (Gasohol) blends on a single-cylinder, four strokes, computerized spark ignition engine fitted with eddy current dynamometer and a precisely adjusted exhaust gas analyser. Under various load, engine speed and compression ratio, the tests were conducted, and the results were recorded. The result shows improved performance parameters of the engine. E25 blend consumed less fuel compared to all blends at maximum speed and the BSFC was about 0.32 kg/kW-hr. The thermal break efficiency of ethanol-gasoline blends was found to be increased compared to gasoline. Maximum BTE was found to be 27.87% for the E35 blend.

The component that can be manufactured using 3-roller bar bending machine are circular washer hav... more The component that can be manufactured using 3-roller bar bending machine are circular washer having internal radius more than 150mm, circular collars, component used for balancing of wind tower assembly, high stiffness spiral spring, etc. For parametric specification of 3-point bar bending machine, it is necessary to analyze the stress induced in rollers and gear teeth radial force. Thus Finite element modeling is necessary and suitable software must be selected for analysis and observation. There are many useful software are available in the market like ANSYS V-13, LS-DYNA, ABAQUS and soon. Hence the 3-point bending machine consists of number of individual parts which to be model and assembled. The 'AUTODESK INVENTOR professional 2013' is best suitable for modeling of this machine (AUTODESK provides ease of man-machine interface, mating of parts both transitional to rotational, constrain edge-surface etc.). It also assists for part detailing and presentation. The finite element analysis is carried out using ABAQUS 6.10 for solving stress distribution across the rolling rollers with billet displacement of 67mm, stress distribution with roller rotation, Gear drive analyses for minimum load case without billet and Gear drive analyses for maximum load case with billet thickness. It also requires the gear train mechanism with the motor to drive roller, to transfer torque to overcome the vertical load acting during operation, and speed reduction for ease bending & rolling process. Thus analysis of load acting on the gear tooth is necessary to set the minimum inside radius of roll for 3-roller bending machine.

Connecting rod is the intermediate link between the piston and the crank. And is responsible to t... more Connecting rod is the intermediate link between the piston and the crank. And is responsible to transmit the push and pull from the piston pin to crank pin, thus converting the reciprocating motion of the piston to rotary motion of the crank. Generally connecting rods are manufactured using carbon steel and in recent days aluminium alloys are finding its application in connecting rod. In this work connecting rod is replaced by aluminium based composite material reinforced with silicon carbide and fly ash. And it also describes the modelling and analysis of connecting rod. FEA analysis was carried out by considering two materials. The parameters like von misses stress, von misses strain and displacement were obtained from ANSYS software. Compared to the former material the new material found to have less weight and better stiffness. It resulted in reduction of 43.48% of weight, with 75% reduction in displacement.