欠膨胀超音速燃气自由射流的工程计算方法

针对欠膨胀燃气射流提出了一种工程计算方法。该方法用准一维完全等熵流计算起始膨胀段，用修正过的动量均化特性模型计算射流初始段，射流主段计算则利用流场的自模性来实现。该方法快速简便，结果能较好地近似欠膨胀火箭燃气射流的射流特性及参数分布。与动量均化特性模型相比，本文的方法在处理射流初始段上更趋合理。

AN ENGINEERING CALCULATION METHOD FOR UNDEREXPANDED SUPERSONIC ROCKET EXHAUST

n engineering calculation method for underexpanded supersonic rocket exhaust ispresented in .this paper. Flow variables in three sections (near-field,primary section of the exhaust andfar-field) are evaluated by using the quasi-one-dimensional isentropic flow model, the modified momentum-averaged behaviour model and the self-preserving model respectively. The method suggestedin this paper can be applied to calculated the boundary of a jet, the velocity and temperature distributions in primary section and in far-field of the exhaust flow field. COmpared with momentum-averagedbehaviour model, this method is more reasonable in dealing with the effect of Mach-disc and oscillating decline in supersonic core in primary section.