Significant growth in aviation industry has brought serious problem of environmental pollution. B... more Significant growth in aviation industry has brought serious problem of environmental pollution. Bio-derived fuels are going to a play a significant role as potential alternative aviation fuels in near future to mitigate the carbon footprint. Ethanol is a candidate biofuel which is widely used in many countries in petrol-ethanol blend for S.I. engines. However, the interest of utilizing biofuels in aviation gas turbine engines is relatively recent. In comparison to ethanol, n-butanol possesses some better fuel properties such as higher energy density, less hygroscopic, lower vapor pressure, higher flash point. Butyl butyrate is another potential candidate which can fulfill the chemical property requirements of alternative aviation fuels. However, compatible substitutes for currently used aviation fuel such as Jet A-1 are still at the early stage of development. The present study deals with experimental investigations of combustion characteristics of aviation kerosene (Jet A-1), butanol, butyl butyrate and blends of the last two fuels with Jet A-1 in a swirl-stabilized gas turbine type combustor test rig. Measurement of temperature and exhaust emissions at the combustor exit, visualization of true-color flame are carried out in order to compare the performance of various fuels relative to Jet A-1.
An analytical performance prediction methodology for annular propulsive nozzles with swirl introd... more An analytical performance prediction methodology for annular propulsive nozzles with swirl introduced in the combustor upstream of the nozzle is presented. The application of that methodology to a specific nozzle design for a free vortex swirl distribution is discussed. Discharge coefficients, specific impulses, and wall pressure distributions are presented. These numerical studies show that the discharge coefficient, thrust, and specific impulse decrease as the amount of swirl increases. This methodology will enable nozzle designers to account for the effects of swirl in nozzle design.
A spacecraft propulsion concept that uses a combination of electrical energy and chemical energy ... more A spacecraft propulsion concept that uses a combination of electrical energy and chemical energy for thrust is explored using thermodynamic modeling calculations. The essence of this concept consists of adding a carefully chosen amount of O2 or F2 oxidizer to the propellant flow of a conventional H2 electrothermal thruster. A general method is given for selecting the fuel:oxidizer ratio so as to optimize the thruster performance for any set of mission constraints.
This paper compares temperature field measurements from selected experiments on a single row, dou... more This paper compares temperature field measurements from selected experiments on a single row, double rows, and opposed rows of jets injected into a ducted cross flow with profiles calculated using an empirical model based on assumed vertical profile similarity and superposition, and distributions calculated with a three-dimensional elliptic code using a standard k-e turbulence model. The empirical model predictions are very good within the range of the generating experiments and the numerical model results, although exhibiting too little mixing, correctly describe the effects of the principal flow and geometric variables.
A new scheme that treats three-dimensional phenomena in MHD generators is introduced. Parabolized... more A new scheme that treats three-dimensional phenomena in MHD generators is introduced. Parabolized Navier-Stokes equations are solved together with the K-e two-equation turbulence model and with the electrodynamic equations. The rational Runge-Kutta method is used along the main flow direction and the Galerkin finite element method in the perpendicular cross section. It is shown that, even when the MHD interaction is still low, three-dimensional effects become clear near open- and short-loading conditions in the case of a diagonaltype generator, since a relatively large Jx component is induced.
Aura Mithra is an aircraft designed with the primary aim of reducing fuel consumption. Noise redu... more Aura Mithra is an aircraft designed with the primary aim of reducing fuel consumption. Noise reduction is also part of the objective. The aircraft mainly features a Blended Wing Body design. It is powered with three engines-two open fan engines and one ultra high bypass engine. The two open fan engines are placed at the wingtips while the ultra high bypass engine is buried in the rear fuselage. The aircraft is provided with elevators and flaperons. It is also equipped with technologies such as micro vortex generators and pneumatic landing gear fairings-all aimed at reducing the drag throughout the mission profile. By combining all these technologies Aura Mithra is estimated to have an increase in fuel efficiency by around 86%. It also reduces the noise produced by certain components without affecting the performance significantly making it less noisy than conventional aircrafts.
Significant growth in aviation industry has brought serious problem of environmental pollution. B... more Significant growth in aviation industry has brought serious problem of environmental pollution. Bio-derived fuels are going to a play a significant role as potential alternative aviation fuels in near future to mitigate the carbon footprint. Ethanol is a candidate biofuel which is widely used in many countries in petrol-ethanol blend for S.I. engines. However, the interest of utilizing biofuels in aviation gas turbine engines is relatively recent. In comparison to ethanol, n-butanol possesses some better fuel properties such as higher energy density, less hygroscopic, lower vapor pressure, higher flash point. Butyl butyrate is another potential candidate which can fulfill the chemical property requirements of alternative aviation fuels. However, compatible substitutes for currently used aviation fuel such as Jet A-1 are still at the early stage of development. The present study deals with experimental investigations of combustion characteristics of aviation kerosene (Jet A-1), butanol, butyl butyrate and blends of the last two fuels with Jet A-1 in a swirl-stabilized gas turbine type combustor test rig. Measurement of temperature and exhaust emissions at the combustor exit, visualization of true-color flame are carried out in order to compare the performance of various fuels relative to Jet A-1.
An analytical performance prediction methodology for annular propulsive nozzles with swirl introd... more An analytical performance prediction methodology for annular propulsive nozzles with swirl introduced in the combustor upstream of the nozzle is presented. The application of that methodology to a specific nozzle design for a free vortex swirl distribution is discussed. Discharge coefficients, specific impulses, and wall pressure distributions are presented. These numerical studies show that the discharge coefficient, thrust, and specific impulse decrease as the amount of swirl increases. This methodology will enable nozzle designers to account for the effects of swirl in nozzle design.
A spacecraft propulsion concept that uses a combination of electrical energy and chemical energy ... more A spacecraft propulsion concept that uses a combination of electrical energy and chemical energy for thrust is explored using thermodynamic modeling calculations. The essence of this concept consists of adding a carefully chosen amount of O2 or F2 oxidizer to the propellant flow of a conventional H2 electrothermal thruster. A general method is given for selecting the fuel:oxidizer ratio so as to optimize the thruster performance for any set of mission constraints.
This paper compares temperature field measurements from selected experiments on a single row, dou... more This paper compares temperature field measurements from selected experiments on a single row, double rows, and opposed rows of jets injected into a ducted cross flow with profiles calculated using an empirical model based on assumed vertical profile similarity and superposition, and distributions calculated with a three-dimensional elliptic code using a standard k-e turbulence model. The empirical model predictions are very good within the range of the generating experiments and the numerical model results, although exhibiting too little mixing, correctly describe the effects of the principal flow and geometric variables.
A new scheme that treats three-dimensional phenomena in MHD generators is introduced. Parabolized... more A new scheme that treats three-dimensional phenomena in MHD generators is introduced. Parabolized Navier-Stokes equations are solved together with the K-e two-equation turbulence model and with the electrodynamic equations. The rational Runge-Kutta method is used along the main flow direction and the Galerkin finite element method in the perpendicular cross section. It is shown that, even when the MHD interaction is still low, three-dimensional effects become clear near open- and short-loading conditions in the case of a diagonaltype generator, since a relatively large Jx component is induced.
Aura Mithra is an aircraft designed with the primary aim of reducing fuel consumption. Noise redu... more Aura Mithra is an aircraft designed with the primary aim of reducing fuel consumption. Noise reduction is also part of the objective. The aircraft mainly features a Blended Wing Body design. It is powered with three engines-two open fan engines and one ultra high bypass engine. The two open fan engines are placed at the wingtips while the ultra high bypass engine is buried in the rear fuselage. The aircraft is provided with elevators and flaperons. It is also equipped with technologies such as micro vortex generators and pneumatic landing gear fairings-all aimed at reducing the drag throughout the mission profile. By combining all these technologies Aura Mithra is estimated to have an increase in fuel efficiency by around 86%. It also reduces the noise produced by certain components without affecting the performance significantly making it less noisy than conventional aircrafts.
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Papers by MANISH KUMAR
combustor upstream of the nozzle is presented. The application of that methodology to a specific nozzle design
for a free vortex swirl distribution is discussed. Discharge coefficients, specific impulses, and wall pressure
distributions are presented. These numerical studies show that the discharge coefficient, thrust, and specific impulse
decrease as the amount of swirl increases. This methodology will enable nozzle designers to account for the
effects of swirl in nozzle design.
explored using thermodynamic modeling calculations. The essence of this concept consists of adding a carefully
chosen amount of O2 or F2 oxidizer to the propellant flow of a conventional H2 electrothermal thruster. A
general method is given for selecting the fuel:oxidizer ratio so as to optimize the thruster performance for any set
of mission constraints.
and opposed rows of jets injected into a ducted cross flow with profiles calculated using an empirical model
based on assumed vertical profile similarity and superposition, and distributions calculated with a three-dimensional
elliptic code using a standard k-e turbulence model. The empirical model predictions are very good within
the range of the generating experiments and the numerical model results, although exhibiting too little mixing,
correctly describe the effects of the principal flow and geometric variables.
Navier-Stokes equations are solved together with the K-e two-equation turbulence model and with the electrodynamic
equations. The rational Runge-Kutta method is used along the main flow direction and the Galerkin
finite element method in the perpendicular cross section. It is shown that, even when the MHD interaction is still
low, three-dimensional effects become clear near open- and short-loading conditions in the case of a diagonaltype
generator, since a relatively large Jx component is induced.
combustor upstream of the nozzle is presented. The application of that methodology to a specific nozzle design
for a free vortex swirl distribution is discussed. Discharge coefficients, specific impulses, and wall pressure
distributions are presented. These numerical studies show that the discharge coefficient, thrust, and specific impulse
decrease as the amount of swirl increases. This methodology will enable nozzle designers to account for the
effects of swirl in nozzle design.
explored using thermodynamic modeling calculations. The essence of this concept consists of adding a carefully
chosen amount of O2 or F2 oxidizer to the propellant flow of a conventional H2 electrothermal thruster. A
general method is given for selecting the fuel:oxidizer ratio so as to optimize the thruster performance for any set
of mission constraints.
and opposed rows of jets injected into a ducted cross flow with profiles calculated using an empirical model
based on assumed vertical profile similarity and superposition, and distributions calculated with a three-dimensional
elliptic code using a standard k-e turbulence model. The empirical model predictions are very good within
the range of the generating experiments and the numerical model results, although exhibiting too little mixing,
correctly describe the effects of the principal flow and geometric variables.
Navier-Stokes equations are solved together with the K-e two-equation turbulence model and with the electrodynamic
equations. The rational Runge-Kutta method is used along the main flow direction and the Galerkin
finite element method in the perpendicular cross section. It is shown that, even when the MHD interaction is still
low, three-dimensional effects become clear near open- and short-loading conditions in the case of a diagonaltype
generator, since a relatively large Jx component is induced.