Design Optimization Method And Performance Research Of Streamline-traced Busemann Inlet

This research concentrates on the Busemann inlet. Using a combination of theoretical analyses and numerical simulations, the effects of three-dimensional inlet design parameters on inlet performance are investigated systematically. The concept of multi-objective design optimization is introduced into the streamline-traced Busemann inlet design. With the mended viscous correction method, the design level of the three-dimensional inlet is improved.The research methods in the paper, including design of experiments, surrogate models and optimization algorithm, are introduced. Their basic theory and relating details are explained. Besides, the numerical simulation method is constructed and tested by comparing the theoretical results and the inviscid result of a baseline Busemann inlet. The flowfield of the baseline Busemann inlet is analyzed and the viscous effect on inlet is studied.The paper conducts the researches of the design Mach number and truncation angle on the Busemann inlet performance systematically. On cruise condition, decreasing the design Mach number within a small range can dramatically reduce the drag coefficient, but decreasing the design Mach number too much will cause overall inlet performance degradation. The higher truncation angle leads to stronger shocks, higher pressure ratio, higher drag coefficient, lower total pressure recovery coefficient and lower exit Mach number.The parametric model of streamline-traced Busemann inlet is established. The inlet is researched with a combination of the Optimal Latin hypercube design, Kriging surrogate model, Multi-Objective Particle Swarm Optimization and numerical simulations. The optimization result is verified by numerical simulation and the deviations of object function between optimization result and simulation result is less than 3%. Compared to the initial inlet, the overall performance of the optimized inlet is improved dramatically. Based on the Pareto results, the inlet length and the drag coefficient can’t reach the best results at the same time, so as the inlet length and the pressure ratio. When the drag coefficient gets bigger, the pressure ratio also gets bigger while the total pressure recovery coefficient gets smaller. The total pressure recovery coefficient is in proportion to the inlet length and in inverse proportion to the pressure ratio. With the sensitivity analysis method, the relationships between the design parameters and object function are studied. The results shows, couple effects between design parameters exist and truncation angle influences the inlet performance most.Based on the semi-empirical formula of the flat turbulence, an improved viscous correction method is proposed. The method can effectively improve the overall performance of the baseline Busemann inlet without changing the contraction ratio. The flowfield structure of the baseline Busemann inlet is also improved.