DEFINITION:

Heat transfers concern mainly the combustor, the turbine and the heat exchangers, if present. In the combustor heat transfers are of two types : convective and radiative. The effect can be damages of the combustor wall through hot points or thermal fatigue due to accumulation of ignition and extinction in the successive flight cycles. The convective heat transfers are due to the direct contact of reacting hot flows with walls. The solutions go through the mastering of fluid dynamics and aerothermochemistry and more precisely of the techniques of wall cooling by film or impingement. Numerical simulation and analytic experimentation play a considerable role in this problem. The radiative heat transfers are due mainly to the emission of hot gases and soots ; the wall to wall radiative transfers are less important. In the turbines, heat transfers are of the convective type. They concern mainly three problems: exchanges between main flow and the external wall of the turbine blades with the associated cooling techniques, cooling of the blades by internal air circuits and the transfer of energy in internal rotating cavities in the core of the engine. In this last case, the flow rates being very low, the movements of the fluid in the cavity are completely driven by the friction on the walls, necessitating a great mastering of turbulence phenomena. In the heat exchangers, heat transfers are the reason to use this component. New conceptions of these devices must be developed to meet the requirements of aeronautical constraints as compacity, weights, geometrical adaptation. In the three cases, investigations must be coupled to the study of conductive heat transfers inside the materials.

(Source: ACARE Domain 305)

SUBDOMAINS:

1. Turbulence
2. Rotating flows
3. Radiation
4. Diagnostics