超临界压力下航空煤油RP-3焓值的测量及换热研究

基于能量守恒原理提出了一种超临界压力下中国3号喷气燃料RP-3焓值的测量方法,同时对不同超临界压力下RP-3在323~843 K内的焓值进行了测量.结果表明当燃油温度低于其临界温度时,不同超临界压力下燃油的焓值几乎是一样的,当温度高于临界温度后,不同压力下RP-3焓值之间的差异随着压力的升高而缩小.另外,根据焓值曲线计算出的燃油温度及吸热量与先前已做的其他流动与换热实验中的测量数据进行了对比,结果表明该焓值是准确可靠的,满足未来航空发动机内空油换热器的设计要求.最后,研究了热流密度对超临界煤油换热的影响,结果显示当燃油对比温度小于1.179(760 K)时,Nu数随着热流密度的增加而增加.

Enthalpy measurement and heat transfer investigation of RP-3 kerosene at supercritical pressure

A method of measuring the enthalpy of China's No.3 jet fuel RP-3 at supercritical pressure was proposed based on the principle of energy conservation.At the same time,the enthalpy of RP-3 at different supercritical pressures between 323K and 834K was measured.The results indicate that,the enthalpy of RP-3 at different pressures is almost the same when the fuel temperature is lower than its critical temperature.When the fuel temperature is higher than its critical temperature,the difference of enthalpy at different supercritical pressures declines with the growing pressure.In addition,the temperature of RP-3 calculated by the curve of enthalpy had been compared with the measurement value,showing that the measurement of enthalpy is accurate and reliable.At last,the influence of heat flux on heat transfer of RP-3 was studied.The test results indicate that the Nusselt number increases with heat flux if the bulk fuel temperature Tb/Tc is lower than 1.179(760K).