超燃冲压发动机尾喷管流线追踪设计

Design of scramjet nozzle based on streamline tracing technique

关键词:  三维尾喷管设计  流线追踪  超燃冲压发动机

Key words:  Design of three-dimensional nozzle  Streamline tracing  Scramjet

摘要:

为了满足超燃冲压发动机三维流道排气系统一体化设计需要,基于轴对称最大推力喷管流动的基准流场,采用流线追踪方法发展了三维尾喷管构型设计技术。根据典型的高超声速飞行条件,设计得到了进口方形,尺寸50mm×50mm,长度560mm,出口高度147mm的三维尾喷管无粘构型,并对其进行了粘性修正。对该尾喷管构型在设计状态进行了无粘和有粘流场计算,得到了推力和升力等性能参数,并对其流场结构有了初步的认识。计算发现,流线追踪构型能有效增大推力,而粘性力是造成推力损失的重要因素。

Abstract:

To design the exhaust system for scramjet with three-dimensional flowpath, a method for designing three-dimensional scramjet nozzle was developed. It employed streamline tracing technique based on flowfield of axisymmetric nozzle with optimum thrust. According to a typical hypersonic flight condition, an inviscid nozzle with rectangular entrance of 50mm×50mm, length of 560mm and height of exit 147mm was constructed and then the boundary layer correction was applied. Inviscid and viscous flowfields were computed on the design point to get thrust and lift of the nozzle. Compared with two different nozzles constructed with straight walls, it is found that nozzle designed by streamline tracing technique can significantly increase the thrust and the viscous force is an important factor to decrease the thrust.