三维喷管设计

为了简化设计过程并获得满意的设计性能，以圆转方和圆转矩形喷管为例，对已有的三维喷管型面设计方法进行比较和总结，运用数值方法分析了型面转换起始位置和喷管出口高宽比的确定，提出了一套三维型面的直接生成方法，并给出相应的设计准则。经过实际设计和加工的检验，证明了设计方法的工艺可行性。在能够保证三维喷管的制造工艺条件以及冷却通道布置要求下，型面转换的起始位置可以尽量接近喉部；喷管出口截面的宽边不要超过窄边的1．5倍，应尽量接近于方形。

Three-dimensional nozzle design

In order to simplify the design process and obtain satisfying performances,taking round-to-square and round-to-rectangle nozzles as example,the exiting design methods for complex 3-D nozzles were compared and evaluated.The start position of contour transition and the shape of the exit cross section were analyzed by numerical simulation.A direct method for 3D contour design was presented and proved to be technically feasible after actual fabrication.Two design criteria were developed: 1) the start position should be as close as possible to the throat within the technological level;2) the exit cross section should be as similar as possible to a square,and if applying rectangular outlet,the size of the broader side should be 1.5 times greater than the dimension of the narrower side.