Dmitry Davidenko

Numerical Study of the Continuous Detonation Wave Rocket Engine

This paper presents numerical results on the operation of the combustion chamber of a Continuous Detonation Wave Rocket Engine (CDWRE). The propagation of a transversal detonation wave in a layer of continuously injected gaseous mixture H2-O2 has been simulated by a reactive high-resolution Euler code in a 2D approach with periodicity boundary conditions. A parametric study has been conducted to investigate the effect of the injection parameters (injector relative area and injection pressure), combustion chamber length, and spacing between successive detonation fronts on the integral characteristics of the combustion chamber operation. It is found that the detonation wave stably propagates at the Chapman-Jouguet velocity. The spatial period between successive detonations is a geometric scaling factor whereas the injection pressure is a scaling factor for the injection mass flux and the wall pressure. The injection mass flux is the main quantity characterizing the detonation propagation conditions.

Systematic Numerical Study of the Supersonic Combustion in an Experimental Combustion Chamber

A systematic computational study has been conducted on the supersonic combustion of a hydrogen jet in the LAERTE combustion chamber, which was experimentally tested at ONERA. The fuel jet is injected at Mach 2 along the chamber axis into a hot flow of vitiated air. The conditions in the vitiated air flow are: Mach number of 2, total temperature about 1850 K. By assuming a two-dimensional axisymmetric (2DA) configuration of the combustion chamber, a broad parametric study has been performed on the following important factors: boundary conditions, computational mesh adaptation, turbulence and chemical kinetic models, air vitiation. Finally a three-dimensional (3D) simulation has been made to study the 3D effects. The 2DA and 3D simulations are carefully compared with the available experimental data to validate the computational approach. A good agreement is obtained between the simulation and experimental results.

Kinetic Mechanism Validation and Numerical Simulation of Supersonic Combustion of Methane-Hydrogen Fuel

Ignition characteristics of methane can be significantly improved by adding some hydrogen. The aim of the present work is to obtain a suitable kinetic mechanism for the methane -hydrogen fuel and to integrate it into the MSD code. Several comprehensive, skeletal, and reduced kinetic mechanisms have been tested using simple reactor models (shock-tube and perfectly stirred reactor) to identify an appropriate mechanism able to describe combustion parameters of the methane -hydrogen-air reacting system such as temperature profile, ignition delay, and extinction limits. Two new reduced kinetic mechanisms have been derived from the LCSR mechanism for the natural gas. They include respectively 79 and 69 reactions between 21 and 19 species, 5 and 4 of which are supposed in the quasi-stationary state. The new reduced mechanisms provide a good agreement of the combustion parameters with experimental correlations and data from the original comprehensive kinetic mechanism. A series of 2D numerical simulations of a reacting methane -hydrogen supersonic jet in a duct have been performed to assess the MSD performance with a new kinetic mechanism. The duct configuration corresponds to that of the LAERTE facility at ONERA. These results are considered as a first approach to plan future experimental studies of methane supe rsonic combustion and as a contribution to the current activity in the field of hype rsonic propulsion.

Use of the Adaptive Mesh Refinement for 3D Simulations of a CDWRE (Continuous Detonation Wave Rocket Engine)

The paper presents the computational method and results of 2D and 3D numerical simulations of the flowfield in Continuous Detonation Wave Engine (CDWE) chambers of different geometries. Numerical simulations have been performed using a detailed thermochemical model of H2-O2 mixture and a high-resolution Euler code with the Adaptive Mesh Refinement (AMR) method. 2D and 3D flowfields are described and their comparative analysis is conducted in order to demonstrate 3D effects. It has been found that the 3D flow has specific features due to the detonation reflection from the outer cylindrical wall. The dependence of 3D effects on the chamber diameter and width is investigated. Nomenclature Aj = net area of injector throats Aw = overall area of injection wall D = detonation propagation velocity with respect to fresh mixture dm = mean diameter of combustion chamber gj = injection mass flux

Theoretical and Numerical Studies on Continuous Detonation Wave Engines

The paper presents the scope of theoretical and numerical studies conducted at ICARECNRS on the Continuous Detonation Wave Engine (CDWE). The last part is devoted to a comparative performance analysis of two ideal engines fed with gaseous H2 and O2: conventional rocket engine (CRE) and continuous detonation wave rocket engine (CDWRE). Flow parameters in main cross sections and the engine performance are evaluated using a global 0D approach with a detailed thermochemical model of equilibrium combustion products. Performance results are obtained in wide rages of mixture ratio, injection pressure, and nozzle exit pressure. It is shown that the CDWRE has an important advantage over the CRE in terms of cycle work and specific impulse.

Numerical Modeling of Inert and Reacting Compressible Turbulent Jets

§The problem of application of the k-e turbulence model to the numerical simulation of compressible round jets is analyzed by comparing experimental and numerical results. A limiting of the Pope correction is proposed to account for the vortex stretching and preserve the computational stability. The limited Pope correction is validated in case of an incompressible round jet in a slow coflow. Two variants of the Sarkar compressibility correction are validated for compressible plane mixing layers with different convective Mach numbers. The Sarkar and limited Pope corrections are then tested for several compressible round jets in still air and supersonic coflow. The simulations have demonstrated a good performance of the k-e model with the two corrections. The effect of the turbulent Schmidt number is investigated for compressible round jets of helium and hydrogen in supersonic air coflow. Reactive and non-reactive flows are considered for a hydrogen jet in a supersonic combustion chamber. A close agreement with the experiment has been obtained for the mixing process by adjusting the turbulent Schmidt number.

Numerical simulations of supersonic combustion of methane-hydrogen fuel in an experimental combustion chamber

Publisher Summary This chapter discusses the numerical simulations of supersonic combustion of methane-hydrogen fuel in an experimental combustion chamber that has been performed using a parallelized version of the computer code MSD (ONERA) installed on a PC cluster. The non-equilibrium chemistry was modeled by a reduced kinetic mechanism (LCSR). The MSD code performance has been assessed for various problems and hardware configurations. Results of two-dimensional simulations are presented demonstrating the behavior of the fuel mixture in a burning supersonic jet. In the case of supersonic combustion, chemical kinetics plays an important role because of high flow speeds about 1500 m/s and moderate temperatures in the fuel-air mixing layer. An accurate modeling of the ignition delay is necessary under such conditions. Since the use of comprehensive kinetic mechanisms is prohibitive for multidimensional computations, a reduced mechanism must be accepted as a chemical model. The aim of this chapter is to present an example of supersonic combustion simulation on a PC cluster. One part of the chapter addresses the performance of a parallelized computational fluid dynamics (CFD) code on a PC cluster depending on the computational job and hardware configurations. Another part presents some new results on the combustion process of a CH4-H2 jet in a supersonic flow.