高原环境续航火箭喷管推力降低异常现象

Abnormal phenomenon of thrust reduction of range rocket nozzle under high altitude condition

为了研究某种续航火箭喷管推力的异常现象,采用AUSM＋（advection upstream splitting method）格式、SST（shear stress transport）湍流模型和LU-SGS（lower-upper symmetric Gauss-Seidel）隐式算法,求解二维轴对称RANS（Reynolds averaged Navier-Stokes）方程,对入口压力相同、环境压力不同的该喷管进行了数值模拟,得到了在环境压力为50.67~101.32kPa下其推力特性的差异,并分析了异常现象产生的原因.结果表明：随着环境压力的降低,外喷管出口边界的静推力为负值且绝对值呈现先增加后减小的变化规律.在环境压力为60.80~101.32kPa区间范围时,外喷管出口边界的动推力和总推力变化相对较小,当环境压力小于60.80kPa时,该出口边界的动推力和总推力急剧降低.

To research abnormal phenomenon of thrust reduction of a range rocket nozzle was chosen to study,nozzle with the same inlet pressure and different environment pressures were simulated numerically by applying the AUSM＋（advection upstream splitting method）scheme,SST（shear-stress transport）turbulence model and LU-SGS（lower-upper symmetric Gauss-Seidel）implicit algorithm were used to solve 2-D axial symmetry RANS（Reynolds-averaged Navier-Stokes）equations.The differences in thrust characteristics were obtained when the environment pressure varied from 50.67 kPa to 101.32 kPa,and the cause of these differences was analyzed.Results indicate that static thrust of the outer nozzle exit boundary rises toward the negative direction when the environment pressure gradually decreases,absolute value increases firstly and then decreases.Dynamic thrust and totalthrust of the outer nozzle exit boundary slightly changes at the environment pressure ranging from 60.80 kPa to 101.32 kPa,but dynamic thrust and total thrust of the outer nozzle declines sharply when the environment pressure is less than 60.80 kPa.