关键词: 燃气轮机;排气扩压器;支撑板;气动性能;数值模拟

Abstract: Strut structure design directly affects the flow field and aerodynamic performance of gas turbine exhaust diffuser. Based on the reliability of the numerical method， the exhaust diffuser model with inlet guide vanes and struts was calculated by solving the three-dimensional Reynolds-Averaged Navier-Stokes （RANS） and Realizable k-ε turbulence models， exploring the effects of the cross-sectional shape and tilt design of the strut on the aerodynamic performance of the exhaust diffuser under four kinds of inlet pre-swirl. The results show that when the inlet pre-swirl and the design method of strut are the same， the strut with thinner profile line is more likely to cause the separation of fluid near the strut and the larger wake flow， increasing the total pressure loss. When the cross-sectional shape of the strut is the same， compared with the radial vertical design of the strut， the radial tilt design of the strut makes the change of the passage area of the exhaust diffuser more gentle， so that the total pressure loss coefficient of the exhaust diffuser decreases by 7%~20% under the four types of inlet pre-swirl. When the aspect ratio（d/C） of strut section line is 0.2， relative to the radial vertical design， the static pressure recovery coefficient of the exhaust diffuser with tilt design of strut increases by 4.7% and 3.8% respectively when the inlet pre-swirl is equal to 0.35 and 0.64， however， when the aspect ratio（d/C） of the strut section line is 0.12 and 0.175， the strut tilting design reduces the static pressure recovery performance of the exhaust diffuser when the inlet pre-swirl is equal to 0.64 and 1.00.

Key words: Gas turbine;Exhaust diffuser;Strut;Aerodynamic performance;Numerical simulation