A test case has been defined to investigate experimentally and by numerical simulation the transient ignition phenomenology when igniting coaxial injected O2 and H2 by a laser. Using high-speed photography the temporal evolution of the flame and its anchoring at the injector could be visualized. From the analysis of the flame front movement flame velocities and convection velocities have been determined at specific phases during the ignition transient. 3D simulation were undertaken but not yet achieved., A first step using 2D axisymmetrical model allow to adjust grid, laser ignition modelization and to performe some parameter studies, Ignition was not reached in this configuration but preliminary results are encouraging. Finally, application to the VINCI was described where ignition uses a torch.

Development of liquid rocket engines is still a big challenge for the manufacturers. In the past, the design relied on accumulated know-how and trial and error methods. More recently, numerical tools have been introduced in the design process but could not replace testing. Combustion in rocket engines fed with both liquid oxygen and hydrogen at high pressure (up to 30 MPa) is so complex that modeling and simulation cannot be carried out without extensive validation based on detailed investigation of elementary processes (liquid propellant injection, atomization, droplet vaporization, turbulent mixing, combustion) in well defined configurations and nevertheless representative operating conditions.

During recent years the methods of CARS spectroscopy have been applied to the studies of hydrogen-air and hydrogen-oxygen combustion processes. For accomplishment of spectroscopic gas temperature measurements usually CARS spectra of Q-branches of hydrogen are used in this case [1,2]. Under the real conditions characterized by high pressures of 10 – 100 atmospheres and high temperatures of 2000 – 3000 K registration of CARS spectra should be accomplishes by knowledge of broadening and shift of the Q-branch lines, mainly perturbed by collisions with water molecules. Previous cell experiments conducted up to 900 K in a binary H2-H2O mixture show that for the hydrogen Q-branch lines there exists significant broadening and its dependence on temperature and rotational quantum number [3,4]. In order to obtain line-broadening data for higher temperatures and densities we propose to use a high pressure pulsed H2-O2 burner. The combustion chamber of the burner we used is filled during 30 msec with the help of pulsed valves by a H2/O2 mixture that is later ignited by a spark plug. Combustion products flow into open air through a small slit in the burner walls. Two CARS spectrometers are simultaneously used to probe combustion products in a jet at a distance X/D=1. One of them is tuned to selected hydrogen Q-branch rotational component with further investigation of the width and shift of the CARS line by a Fabry-Perot interferometer. Another spectrometer detects water and hydrogen spectra for density and temperature evaluation. In the present work preliminary results on characterization of our pulsed high pressure burner and some measurements of broadening and shift of the Q-branch lines of hydrogen in combustion products of the pulsed burner are given.

The coherent anti-Stokes Raman spectroscopy (CARS) method has recently been used in the United States and Europe to probe several different types of propulsion systems for air vehicles. At NASA Langley Research Center in the United States, CARS has been used to simultaneously measure temperature and the mole fractions of N2, O2 and H2 in a supersonic combustor, representative of a scramjet engine. At Wright- Patterson Air Force Base in the United States, CARS has been used to simultaneously measure temperature and mole fractions of N2, O2 and CO2, in the exhaust stream of a liquid-fueled, gas-turbine combustor. At ONERA in France and the DLR in Germany researchers have used CARS to measure temperature and species concentrations in cryogenic LOX-H2 rocket combustion chambers. The primary aim of these measurements has been to provide detailed flowfield information for computational fluid dynamics (CFD) code validation.