亚/超临界多相煤油喷嘴流量特性

Mass flow rate characteristics of sub-/supercritical multiphase kerosene fuel nozzle

为了精确设计多相煤油喷嘴,以应用于采用冷却涡轮冷气技术的航空发动机,采用轴对称的模拟喷嘴,在不同的固定喷射压力下,通过调节燃油温度,获得了亚/超临界的燃油流量变化规律。根据煤油相态的分区理论,将流量曲线分为液相区、气液两相区和超临界区,分析不同相态航空煤油流量随喷射状态变化的作用机制,分别给出液相区和超临界区的流量计算方法及气液两相区流量系数的拟合关系式。结果表明:在喷射温度从常温至750 K的范围内,流量在液相区缓慢降低,在气液两相区加速下降,最后经“拐点”温度后进入超临界区缓慢下降。计算结果与试验值最大误差为3.8%,拟合式的相关系数平方为0.947 8,该结果可作为多相喷嘴设计的计算依据。同时获得的流量数据,可以作为喷嘴下游喷射结构的研究的边界条件,支撑先进航空发动机设计研发。

To precisely design multiphase fuel nozzles,so that they can be applied to the aero-engines with the technology of cooling the turbine cooling air,the fuel mass flow rate of sub-/supercritical kerosene in an axisymmetric model nozzle was studied.By adjusting the fuel temperature under multiple sets of fixed injection pressure,the mass flow rate change of sub-/supercritical fuel was obtained.According to the phase conditions of kerosene,the flow rate curves were divided into three phase regimes,i.e.,liquid,gas-liquid,and supercritical,and the mechanisms in the process of flow rate changing with kerosene injection status under different phase conditions were discussed.The flow rate prediction methods in the liquid and the supercritical regime,as well as the fitting correlation of the discharge coefficient in the gas-liquid regime,were proposed.Results showed that,as injection temperature increased from normal temperature to 750 K,the flow rates slowly decreased in the liquid regime,sharply declined in the gas-liquid regime,and then gradually declined in the supercritical regime beyond the“inflection point” temperature.The maximum error between the calculated and experimental results was3.8%,and the square of the correlation coefficient of the fitting correlation was 0.947 8,which can serve multiphase nozzle design.Meanwhile,the acquired mass flow rate data can provide the boundary conditions for the research of injection structures downstream the nozzles,supporting advanced aeroengine design and development.