冲压发动机油箱传热理论研究

Theoretical Study for Heat Transfer of Ramjet Fuel Tank

关键词:  液体燃料冲压发动机  燃油温度  换热系数  传热模型 

Key words:  Liquid fuel ramjet  Fuel temperature  Heat transfer coefficient  Heat transfer model

摘要:

为了研究冲压发动机长时间飞行后燃油温度是否超过所选用非金属材料的承受温度限制,使用试验测量数据构建了油箱内流和外流的传热模型,获取了不同工作状态下油箱内壁面的平均换热系数,拟合了换热系数与飞行马赫数和高度的函数关系式。对极限高温环境,典型理论飞行轨迹下油箱燃油温度和燃油使用率进行了研究。计算结果表明,飞行高度越低,马赫数越大,则换热系数越大。油箱内燃油的质量对燃油温度有重要影响。最终燃油温度不大于非金属材料承受温度180℃。 

Abstract:

In order to study the fuel temperature after the long time flight of the ramjet so as to check whether the fuel temperature is over the limit, the model of the heat transfer between the external flow of the shell and the fuel tank is constructed based on the test data. Under the different work conditions, the heat transfer coefficient of the fuel tank wall is obtained. The functional relation of the heat transfer coefficient with the flight Mach number and altitude is built up. The fuel temperature and the fuel consumption rate are investigated under the extreme temperature environment and the typical flight trajectory. The computed results show that the heat transfer coefficient increases as the altitude decreases and Mach number increases. The remaining fuel quantity has great impact on the final fuel temperature. The maximal fuel temperature is not over the required limit which is 180℃. 