RP-3航空煤油不同替代模型的空化流动特性

Cavitating Flow Characteristics of RP-3 Aviation Kerosene Surrogate Mixture Models

关键词:  RP-3航空煤油  替代模型  空化流动  计算流体力学

Key words:  RP-3 aviation kerosene  Surrogate mixture model  Cavitating flows  Computational fluid dynamics

摘要:

为研究RP-3航空煤油空化流动特性，采用GERG-2004方程构建了4种RP-3航空煤油的物理替代模型并给出其主要物性参数，对收缩扩张流道内航空煤油替代模型、正十二烷(C12H26)和水体的空化流动进行了数值计算研究，计算时考虑了饱和蒸汽压修正及航空煤油物性参数随流场温度变化。结果表明:由45％正十二烷、25%正十烷、5%辛烷、5%甲基环己烷和20%甲苯(摩尔比)组成的替代模型能够较好拟合RP-3的物质属性，可用来替代RP-3进行空化流动计算。常温下航空煤油的初生空化数小于水体，相同空化数下(σ=1.5)，水体的空穴长度约为航空煤油的1.4倍，航空煤油的空化强度更弱，液汽交界面较模糊。随着温度的升高，航空煤油空化热力学效应增强，但其在煤油泵工作温度区域内空化热力学效应不显著，在煤油泵空化性能预测时可以忽略煤油空化热力学效应的影响。

Abstract:

To study the cavitating flow characteristics of RP-3 aviation kerosene，four kinds of RP-3 aviation kerosene surrogate mixture models were established by GERG-2004 equations，and the main physical properties of these surrogate mixture models were illustrated. The modified saturated vapor pressure and material properties at different temperature were applied in the CFD codes. The dodecane and water cavitating flows in a converging-diverging flow channel were calculated. The surrogate C，which is made up of 45%dodecane，25%decane，5%octane，5%methyl cyclohexane，and 20%toluene(mole fraction)，shows better agreement with RP-3 aviation kerosene in certain properties，and then it was considered as RP-3 in cavitating flow computation. The inception cavitation number of aviation kerosene is smaller than that of water at room temperature. The cavity length of water is approximately 1.4 times that of aviation kerosene when cavitation number is 1.5，and the intensity of cavitation is weaker than water under the same conditions and the cavity of aviation kerosene is mushy. As temperature increases，the intensity of thermodynamic effects on aviation kerosene cavitating flow increases，however，it is not notable during the working temperature of aviation kerosene pumps. Thus thermodynamic effects of cavitation could be ignored in the prediction of cavitating flow characteristics of aviation kerosene pumps.