The characteristics of propellant injection, mixing, and combustion have a profound effect on liquid rocket engine performance. The necessity of raising rocket engines performance requires a combustion chamber operation often in a supercritical regime. A supercritical combustion model based on a one-phase multi-components approach is developed and tested on a non-premixed H2-O2 flame configuration. A two equations turbulence model is used for describing the jet dynamics where a limited Pope correction is added to account for the oxidant spreading rate. Transport properties of the mixture are calculated using extended high pressure forms of the mixing rules. An equilibrium chemistry scheme is adopted in this combustion case, with both algebraic and stochastic expressions for the chemistry/turbulence coupling. The model was incorporated into a computational fluid dynamics commercial code (Fluent 6.2.16). The validity of the present model was investigated by comparing predictions of temperature, species mass fractions, recirculation zones and visible flame length to the experimental data measured on the Mascotte test rig. The results were confronted also with advanced code simulations. It appears that the agreement between the results was fairly good in the chamber regions situated downstream the near injection zone.

In the present work, an unsteady analysis is carried out for the thermal characterisation of a firefighter protective clothing. Coupled radiative and conduction heat transfers are considered inside the clothing with a focus on the thermal level on the first skin layer. The protective garment is modelled as a 1D solid medium, featuring three layers of tissues, separated by several air-gaps. A parametric analysis is performed in the aim to predict the effect of conductive and radiative tissue's properties fluctuation on the first skin's layer temperature. The thermal balance equations are written in a finite element (FE) formulation and solved using the COMSOL Multiphysics® software. Predictions were provided for the temperature and heat flux distributions in the fabric, skin, and air-gap as a function of time, as well as the time to receive skin burn injuries. The results obtained were compared with stationary 2-D calculations, and faced to unsteady simulations, based on the finite volume method. A 50% relative reduction in the absorptivity of the skin (in the case of wearing a fine knitted fabric) makes it possible to reduce the surface temperature of the skin to a tolerable value.

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