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 3-D 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.