Heat transfer deterioration produces local wall temperature peaks and may endanger actively cooled scramjet engines. The heat transfer deterioration of supercritical-pressure -decane at different flight accelerations is simulated to represent accelerating hypersonic vehicles. Two types of heat transfer deterioration are observed. The type 1 heat transfer deterioration, which appears at the initial heated section, is due to the formation of the thermal boundary layer. The type 2 heat transfer deterioration, which can be identified with an M-shaped velocity profile, appears because of the reduction of turbulent diffusion. The heat transfer deterioration onset parameter, which is defined as the ratio of heat flux to mass flux in case of incipient heat transfer deterioration, is obtained at both positive and negative flight accelerations. A positive flight acceleration value indicates that the flow direction and the acceleration direction is the same, and a negative value indicates that the two directions are opposite. Both types of heat transfer deterioration onset parameter increase linearly as the positive acceleration increases. The type 2 heat transfer deterioration onset parameter cannot be identified when the negative acceleration is less than a certain value. Correlations for the heat transfer deterioration onset parameter as a function of flight acceleration are fitted and can be adopted in the design of the active cooling system of scramjet engines.
Flight Acceleration Effect on Heat Transfer Deterioration of Actively Cooled Scramjet Engines
Journal of Thermophysics and Heat Transfer ; 30 , 2 ; 279-287
2016-01-11
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Design, Fabrication and Testing of an Actively Cooled Scramjet Propulsion System
British Library Conference Proceedings | 2003
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