Design method for multi-dimensional deflected serpentine nozzle with abnormal exit

The aerodynamic profile design of multi-dimensional deflected serpentine nozzles with high aerodynamic performance and complex configurations is one of the crucial technologies for stealth aircraft with integrated wing-body layouts. By improving the Lee curve method and multiparametric coupled method, we propose a design method for multi-dimensional deflected serpentine nozzles with an abnormal exit, and realize the multi-dimensional deflected serpentine centerline design with vector angles and the cross-sectional transition from the circular inlet to the abnormal exit. This method can be used for the aerodynamic profile design of multiple serpentine nozzles with conventional and space-confined layouts, such as multi-dimensional deflected serpentine nozzles, serpentine nozzles with vector angles, serpentine nozzles with unsymmetrical abnormal exits, and serpentine nozzles for single and twin aeroengine layouts. The proposed design method is verified by the numerical simulation method and the small turbojet engine test. The results show that the discharge and thrust coefficients of the ultra-compact serpentine nozzle designed with the space-confined layout reach 0.982 and 0.989, respectively, under the critical condition, and are no smaller than 0.984 and 0.992, respectively, under the overcritical condition. Those of the multi-dimensional deflected serpentine nozzle designed with the space-confined layout reach 0.980 and 0.986, respectively, under the critical condition and are no smaller than 0.981 and 0.990, respectively, under the overcritical condition. The total thrust of engine after installing the juxtaposition serpentine nozzles designed with the twin engine layout is no more than 4.58% lower than that with the original nozzle. The designed serpentine nozzles have better aerodynamic performance.