超临界喷射受环境和喷射参数影响的数值研究

基于PR(Peng-Robinson)状态方程,采用二维轴对称的两相流控制方程和相关文献中的混合规则,建立了超临界燃油喷射的数值模型并采用预处理方法进行求解.以正癸烷为替代燃料研究了超临界燃油喷射到静止超临界氮气环境中时射流长度和射流扩张角的变化规律.结果表明:超临界射流长度和射流扩张角随环境压力的升高而减小,随环境温度和喷射温度的升高而增加,且超临界射流长度受环境和喷射参数影响的敏感性稍高于射流扩张角.分析认为影响超临界喷射的两个主要因素是喷射密度比和喷射动量,且后者占主导地位.

Numerical investigation on effects of ambient and injection parameters on supercritical injection

Based on the PR(Peng-Robinson) equation of state, two-dimensional axisymmetric governing equation of two-phase flow was introduced to establish a numerical model of supercritical injection by employing the mixing rule described in relevant references. And preconditioning method was used for solving, while n-decane was used as an alternative of liquid hydrocarbon fuel to investigate the supercritical injection characteristics in a quiescent supercritical nitrogen chamber. The jet length and jet spreading angle affected by ambient and injection parameters were separately analyzed. This demonstrates that jet length and jet spreading angle decrease with the increasing ambient pressure, but increase with the increasing ambient and injection temperature. The sensitivity of supercritical jet length affected by ambient and injection parameters is higher than jet spreading angle. It is deemed that the injection density ratio and injection momentum are two main influential factors to the supercritical injection, and the injection momentum is considered to be the dominant factor.