超燃冲压发动机壁面热量的利用潜力分析

Analysis of Potential Usage for Heat of Scramjet Wall

在高马赫数飞行下,用燃料冷却超燃冲压发动机壁面的冷却需求量大于发动机燃烧量。为了降低燃料的冷却量以及实现燃料冷却量和燃烧量的匹配,采用可用能分析法对超燃冲压发动机壁面热量的利用潜力进行分析。发动机壁面热量特性及燃料的冷却特性决定可用能大小。根据发动机壁面温度分布、热流密度分布及燃料的冷却过程温度分布计算可用能。该方法得出:在壁面最高温度为1200K时,传入壁面的热量为554.4k W,其中理论可用能为331.6k W。没有利用其热量实现热量转换时需要的燃料冷却流量为0.616kg/s,最大限度利用热量实现能量转换输出可用功时只需要燃料冷却流量为0.2476kg/s,降低了燃料的冷却需求量。

Coolant flow rate of fuel for scramjet exceeds stoichiometric flow rate in the high flight Mach number. In order to decrease the coolant flow rate of fuel and implement the matching between coolant flow rate and stoichiometric flow rate,the potential working for the heat of scramjet wall has been analyzed by exergy method. It is determining the quantity of exergy that the properties of heat of scramjet wall and the cooling of fuel.The exergy has been calculated according to the distribution of scramjet wall temperature,scramjet wall heat flux and the distribution of fuel cooling process temperature. It has been conclusion that the heat of scramjet wall is 554.4k W and the exergy is 331.6k W when the maximum temperature of scramjet wall is 1200 K. It is also concluded that the coolant flow rate of fuel is 0.616kg/s for scramjet without energy conversion while the coolant flow rate of fuel is only 0.2476kg/s with energy conversion. It decreased the coolant flow rate of fuel.