Controlling the rule of coke depositions of hydrocarbon fuels in channel to intensify heat transfer under supercritical conditions

As the temperature in chamber of scramjet engine would be very high, for the moment, endothermic hydrocarbon fuels instead of the conventional aviation oils would be used in active cooling. However, when endothermic hydrocarbon fuels were heated, it would be occurred coke deposition on the in-wall of cooling channels. In this paper, the study is focused on the influence of coke depositions on heat transfer by experiments and numerical calculations. Along with the time of heating, the thickness of coke depositions in channel varied. At the beginning of heating, a few of cokes are deposited on the in-wall of channels. Heat transfer is intensified as a result of the roughness of coke. Then, the coke thickness increases, the efficiency of heat transfer gradually reduces. At this time, other conditions were varied to control the rule of coke depositions in order to increase the intensity of heat exchange. For example, the flux of fuels would be increased to overcome the clinging force between cokes and channel wall, and so on.