Preliminary Experimental Study On Inlet Of Ram-Air Hypervelocity Optical Dome

When the optical imaging guided missile is flying at hypervelocity in the near ground,the supersonic film used for window cooling and the cooling for imaging devices requires a gas source with high pressure and mass flow rate.Relying on the conventional missile-carrying tank scheme is hard to complete this long-term supply of gas.It will not only increase the difficulty of preloading on the ground,but also occupy the missile’s load capacity and the internal space.To this end,this thesis proposes to use the inlet technology of ramjet to complete the cooling gas supply task by capturing the high total pressure flow during flight.The problem of the requirement of the supersonic cooling film on hypervelocity optical dome and its solving are investigated.However,due to the different demands of the cooling gas and engine combustion,further research of the inlet is needed on the performance focus and design modification.Firstly,based on the supersonic cooling film on hypervelocity optical dome,the exact demands of gas supply in pressure and mass flow rate are obtained,combined with the CFD(computational fluid dynamics)results.Secondly,the method,that inlet for gas supplying and liquid nitrogen for cooling,is proposed.Its system consistent and work process are described.The analysis about the difference of the inlet for the film cooling and the inlet of the ramjet engine is then carried out.Subsequently,an experimental study of air inflating is performed based on the sidewall compression inlet.The forebody is a blunt flat plate with an angle of attack.The gas path is drawn from the bottom of the inlet and connected to a tank.With four different sidewall configurations,experiments of different lip position and sidewall spacing are performed at Mach number 3.The variation law of the tank equilibrium pressure and average flow rate is obtained.Through the flow field display results of the symmetry plane and the wall pressure data,the causes of the change in the inflating performance are reasonably analyzed and explained.Finally,the experiment of the sidewall compression inlet with a double cone blunt forebody model is performed.Using the sidewall configuration with the highest total pressure recovery coefficient in the previous chapter,the experiments of fixed sidewall spacing and different lip position at Mach number 3 and 6 are carried out.The temperature measurement is added.The law is slightly different from that in the last chapter.Combined with the CFD results,the performance of the inlet is analyzed.Furthermore,the phenomenon of airflow’s high temperature under high total temperature flow conditions is discussed.