发动机冷却燃料超临界压力下做功潜力(火用)分析

摘要

Coolant flow rate of fuel for scramjet exceeds stoichiometric flow rate in the high flight Mach number.In order to lower the coolant flow rate of fuel and implement the matching between coolant flow rate and stoichiometric flow rate, the potential working for the cooling fuel was analyzed by exergy method.The properties of the cooling of fuel at supercritical pressures determines the quantity of exergy.The exergy was calculated according to the distribution of scramjet wall's temperature, scramjet wall's heat flux, and the exergy equilibrium equation was given.It is concluded that the heat of scramjet wall is 562.4 kW and the exergy is 541.3 kW when the maximum temperature of scramjet wall is 1200 K.It is also concluded that the potential working is lowered while the coolant flow rate of fuel is increased and the output temperature of fuel is increased, and the potential working is not changed when the output pressure of fuel is increased.%在高马赫数飞行下,超燃冲压发动机的燃料冷却量大于燃料燃烧量.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,采用分析法对超燃冲压发动机壁面燃料冷却工质在超临界压力下进行做功潜力分析.发动机壁面冷却燃料的特性决定其热量大小.根据发动机壁面温度分布、热流密度分布计算热量,建立稳定流动燃料工质的(火用)平衡方程.结果表明:在壁面最高温度为1200 K时,传入壁面的热量为562.4 kW,其中理论热量为541.3 kW;冷却燃料工质流量增加,最大输出功减小;燃料工质出口温度增加,输出功减小;燃料工质出口压力增加,输出功基本不变.