关键词: 推进系统;凹面+;冲击;传热

Abstract: The characteristics of local heat transfer on concave target surface in single jet impingement under small jet-to-target spacing was studied.Impingement Reynolds number was in the range of 20 000～30 000,and the ratio of the jet impingement distance to the diameter of the jet hole H/D was 0.2～1.0.And the secondary heat transfer peak in axial direction was observed because of the acceleration of cooling air,which was induced by the high pressure in jet stagnation region.These secondary peak of heat transfer is much more distinguished in small jet-to-target spacing such as H/D=0.2.In radial direction,the secondary peak of heat transfer was also observed because of the spray jet in radial,which was induced by the too small distance between end wall of impingement nozzle and concave surface.With the increasing of H/D,the secondary peak of heat transfer in radial direction disappeared rapidly.All the results show that the heat transfer increased with the increasing of impingement Reynold number ane the decreasing of H/D.The maximum local and average heat transfer can be achieved in the case of H/D=0.2.

Key words: Propulsion system;Concave surface+;Impingement;Heat transfer