Effects of numerical simulation models on thermal characteristics of combustion gas flow ejected from gas oxygen/kerosene rocket engine

Combustion gas flow ejected from a liquid rocket engine can provide an environment of high enthalpy supersonic gas flow field, which is suitable to test the temperature protective ability of the material or a thermal structure. Accurate thermal characteristics of the flow field directly affect the evaluation of test results. For the gas oxygen/ kerosene rocket engine, the process of the fuel and the oxidizer mixture and combustion process in the chamber is complex. Also after the combustion gas is ejected from nozzle, it is mixed with the surrounding air and expansion waves and compression waves appear alternatively. These actors make it difficult to simulate the plume flow field, especially the thermal parameters accurately. In this paper, considering the spray droplet diameter and broken, the Lagrange discrete phase model and two reaction models of kerosene were used to simulate the flow filed in combustion chamber and nozzle to study the effect of atomizing model and chemical reactions models on the combustion chamber and nozzle flow parameters. The plume flow field was then simulated using different chemical models. At the same time, a test is carried out to measure the thermal environment parameters, including static pressure, total pressure and temperature of the combustion gas ejected from the engine. The results of numerical simulation results are compared with the test data and the accuracy of simulation methods were evaluated. The assessment showed that the chemical reaction system has great effect on the temperature in the chamber and nozzle, while the diameter distribution and secondary breakup models have a little impact. The two-step global reaction mechanism will overestimate the temperature and it is appropriate to adopt 10-step chemical reaction system. For the plume field, the numerical simulation achieved good agreement with the test near the nozzle exit, but there are some differences after the wave string. It should be improved from the two aspects of numerical simulation and test.