Experimental Study On Heat Transfer Characteristics Of Emulsified Hydrocarbon Fuel Under Supercritical Pressure

The thermal protection of scramjet has been an important factor restricting its development.At present,the most effective thermal protection technology to solve this problem is the "regenerative active cooling technology",which uses the hydrocarbon fuel carried by the aircraft as the coolant.However,the coking characteristics of hydrocarbon fuel at high temperature will seriously affect the normal operation of the engine.It is found that emulsification of water and hydrocarbon fuel can greatly restrain the coking characteristics of fuel.Therefore,this paper has carried out an experimental study on the formation of emulsified hydrocarbon fuel by emulsification of hydrocarbon fuel and water are needed.This paper based on the regenerative active cooling technology of scramjet is studied,then based on the traditional electric heating test platform of hydrocarbon fuel,an electric heating test platform for emulsified hydrocarbon fuel was designed and built.The basic process of fuel cooling for scramjet was simulated experimentally.Based on the experimental conditions are as follows: The outlet pressure of the experimental section is maintained at 3 MPa,the temperature at the outlet fluid of the heater are450?~750?,and the mass flow rate of fuel are 1.0 g/s,1.5 g/s,2.0 g/s and 2.6 g/s.The heat flux,heat sink and heat transfer capacity of emulsified hydrocarbon fuel with water content of 10%,30% and 50% respectively and hydrocarbon fuel under supercritical pressure were studied experimentally.The analyzed of the experimental results showed that: Under supercritical pressure,the higher the outlet fluid temperature,the greater the heat flux and heat sink ofemulsified hydrocarbon fuel and hydrocarbon fuel;The higher the moisture content,the greater the heat flux and heat sink of emulsified hydrocarbon fuel;The greater the mass flow rate,the greater the heat flux of emulsified hydrocarbon fuel and hydrocarbon fuel,and the heat sink is smaller.Under supercritical pressure,the heat transfer capacity of hydrocarbon fuels in the channel increases gradually along the axial direction of the experimental section;The phenomenon of heat transfer deterioration occurs in emulsified hydrocarbon fuel in the channel.The higher the moisture content is,the earlier the heat transfer deteriorates,and the larger the heat transfer deterioration zone is;The higher the outlet fluid temperature is,the earlier the heat transfer deterioration occurs,which does not affect the heat transfer deterioration region.Comparison of emulsified hydrocarbon fuel and hydrocarbon fuel analyzed showed that: The heat flux,heat sink and heat transfer capacity of emulsified hydrocarbon fuel are higher than those of hydrocarbon fuel.Therefore,as the coolant of the scramjet,the heat transfer and cooling capacity of the emulsified hydrocarbon fuel is better.