Experimental and numerical evaluation of the heat fluxes in a basic two-dimensional motor

In the framework of a study assessing the ablation of Internal Thermal Insulation (ITI) of the Ariane 5 P230 Solid Rocket Booster (SRB), a 2D basic motor has been designed and manufactured at ONERA. During the first phase of the study, emphasis has been put on the heat flux measurements on an inert wall facing a propellant grain. In order to numerically reproduce the increase of the heat transfer exchange coefficient which is experimentally observed when one proceeds from the head-end to the aft-end of the port, a 2D explicit code with a two-equation turbulence model has been used. It is found that the computed heat transfer coefficient is closer to the experimental one when a wall law accounting for the mean density variations due to the large temperature gradient near the ITI is used. For this, the ITI is assumed to be completely inert and the wall temperature is imposed. The experimental data for two other tests, not numerically simulated, are also presented.