In this numerical study, supersonic combustion of liquid kerosene in a strut-based combustor is investigated. To this end, three-dimensional compressible, turbulent, nonreacting and reacting flow calculations with a single-step chemistry model have been carried out. For the nonreacting flow calculations, fuel droplet trajectories, degree of mixing, and mixing efficiency are presented and discussed. For the reacting flow calculations, contours of heat release and Mach number and the variation of combustion efficiency, total pressure loss, and thrust profile along the combustor length are used to identify the regions of mixing and heat release inside the combustor. Furthermore, the predicted variation of static pressure along the combustor top wall is compared with experimental data. The significance of the lateral spread of the fuel and the extent of the mixing process, especially for a liquid fuel such as kerosene, on the prediction of heat release is discussed in detail. Copyright © 2010 by Luca Boccaletto.

Viswanathan T. Babu

Department of Mechanical Engineering

Prabhat Ranjan Behera

CHEMISTRY MODELS

Combustion efficiencies

DEGREE OF MIXING

Experimental data

FUEL DROPLETS

Heat release

Lateral spread

Mixing efficiency

MIXING PROCESS

NONREACTING FLOW

Numerical investigations

Numerical studies

Reacting flows

Single-step

Static pressure

Supersonic combustion

Total-pressure loss

combustion

Drop formation

Fuels

Kerosene

Liquids

Mach number

Mixing

Struts

three dimensional

Combustors

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IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Numerical investigation of the supersonic combustion of kerosene in a strut-based combustor

Journal of Propulsion and Power

Results from 3D, compressible, unsteady Favre-averaged calculations of transverse injection into a supersonic cross flow are reported. Four injector geometries, namely, circular, wedge, diamond, and chevron, have been investigated. The effectiveness of the chevron injector is demonstrated by comparing performance metrics, such as degree of mixing and total pressure loss, against those of the other injectors. The results show that the chevron injector provides better mixing and spreading compared to other injectors, with almost the same total pressure loss. Furthermore, for the operating conditions studied, the chevron-penetration angle is shown to have a minimal impact on the mixing and the total pressure loss. © 2014 by ASME.

Journal of Fluids Engineering, Transactions of the ASME

Transverse injection into a supersonic cross flow through a circular injector with chevrons

In this numerical study, supersonic combustion of kerosene in three model combustor configurations is investigated. To this end, 3-D, compressible, turbulent, nonreacting, and reacting flow calculations with a single step chemistry model have been carried out. For the nonreacting flow calculations, the droplet diameter distribution at different axial locations, variation of the Sauter mean diameter, and the mixing efficiency for three injection pressures are presented and discussed. In addition, the effect of turbulent dispersion on the mixing efficiency is studied using a stochastic model in conjunction with the two-equation shear stress transport κ-ω turbulence model. For the reacting flow calculations, contours of heat release and axial velocity at several axial locations are used to identify regions of heat release inside the combustor. Combustion efficiency predicted by the present results is compared with earlier predictions for all the combustor models. Furthermore, the predicted variation of static pressure along the combustor top wall is compared with experimental data reported in the literature. Calculations show that the penetration and spreading of the fuel increases with an increase in the injection pressure. Predicted values of the combustion efficiency are more realistic when the spray model is used for modelling the injection of the fuel. The importance of the mixing process, especially for a liquid fuel such as kerosene, on the prediction of heat release is discussed in detail.

Mixing and combustion characteristics of kerosene In a model supersonic combustor

In this paper, numerical simulations of a full scale concept supersonic combustor using kerosene fuel are presented. Results are reported first for a baseline model. These results are then used for identifying the shortcomings in this model, which allows improvements to be made. In particular, the spacing between the ramps is widened so that the heat addition is not confined to a short region and is distributed over a larger volume. Also the design of fuel supply lines has been reworked so that they do not obstruct the supersonic flow. Details of the flow field inside the combustor such as contours of static pressure, static temperature, species mass fraction, reaction rate and Mach number are discussed. Wall static pressure distribution along the top wall of the combustor is presented. Intricate details of the flow field such as separation zones, shocks and expansion fans and their interaction are also brought out. Finally, thrust developed by the combustor is calculated using two different methods. Copyright © 2009 Inderscience Publishers.

Progress in Computational Fluid Dynamics

Evaluation of a ramp cavity based concept supersonic combustor using CFD

In this numerical study, the influence of chemistry models on the predictions of supersonic combustion in a model combustor is investigated. To this end, 3D, compressible, turbulent, reacting flow calculations with a detailed chemistry model (with 37 reactions and 9 species) and the Spalart-Allmaras turbulence model have been carried out. These results are compared with earlier results obtained using single step chemistry. Hydrogen is used as the fuel and three fuel injection schemes, namely, strut, staged (i.e., strut and wall) and wall injection, are considered to evaluate the impact of the chemistry models on the flow field predictions. Predictions of the mass fractions of major species, minor species, dimensionless stagnation temperature, dimensionless static pressure rise and thrust percentage along the combustor length are presented and discussed. Overall performance metrics such as mixing efficiency and combustion efficiency are used to draw inferences on the nature (whether mixing- or kinetic-controlled) and the completeness of the combustion process. The predicted values of the dimensionless wall static pressure are compared with experimental data reported in the literature. The calculations show that multi step chemistry predicts higher and more wide spread heat release than what is predicted by single step chemistry. In addition, it is also shown that multi step chemistry predicts intricate details of the combustion process such as the ignition distance and induction distance. © 2009 The Combustion Institute.

Combustion and Flame

Investigation of the effect of chemistry models on the numerical predictions of the supersonic combustion of hydrogen

Numerical simulations of the 3D reacting flow in a model supersonic combustor with kerosene as the fuel have been carried out. The combustor entry Mach number is nominally 2.5. Tetrahedral grids with wall y+ less than 75 have been used. Details of the flow field inside the combustor such as contours of static pressure, static temperature, species mass fraction, reaction rate and Mach number are discussed. Also, the variation of metrics such as combustion efficiency and total pressure loss along the length of the combustor are presented. Predicted values of wall static pressure along the top wall of the combustor are compared with previously reported experimental data. The calculations over predict the pressure rise due to combustion in the cavity region, but the overall pressure rise is predicted well. Copyright © 2009 Inderscience Publishers.

Numerical simulation of the supersonic combustion of kerosene in a model combustor

Liquid-Fueled Strut-Based Scramjet Combustor Design: A Computational Fluid Dynamics Approach

Journal	Journal of Propulsion and Power
ISSN	07484658
Open Access	No