Supersonic turbine is widely used in the turbo pump of modern rocket. A preliminary design method for supersonic turbine has been developed considering the coupling effects of turbine and nozzle. Numerical simulation has been proceeded to validate the feasibility of the design method. As the strong shockwave reflected on the mixing plane, additional numerical simulated error would be produced by the mixing plane model in the steady CFD. So unsteady CFD is employed to investigate the aerodynamic performance of the turbine and flow field in passage. Results showed that the preliminary design method developed in this paper is suitable for designing supersonic turbine. This periodical variation of complex shockwave system influences the development of secondary flow, wake and shock-boundary layer interaction, which obviously affect the secondary loss in vane passage. The periodical variation also influences the strength of reflecting shockwave, which affects the profile loss in vane passage. Besides, high circumferential velocity at vane outlet and short blade lead to high radial pressure gradient, which makes the low kinetic energy fluid moves towards hub region and produces additional loss.

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To study how the geometry of the plenum chamber in the bleed system of an axial compressor influences the losses therein and to establish a theoretical loss model for this system, a 1.5-stage axial compressor with a bleed system is studied numerically by means of computational fluid dynamics (CFD). The results show that losses in the bleed system occur mainly in the axisymmetric bleed slot and plenum chamber, accounting for ca. 85% of the total loss. For a bleed system with a vertical axisymmetric slot, the loss is more sensitive to the radial height than to the axial width of the plenum chamber. A loss model for each part of the bleed system is established via theoretical analysis, and then, a model of the overall bleed system is established by combining these submodels. The predictions of the theoretical loss model agree well with the CFD results: the maximum prediction error for the coefficient of the stagnation pressure loss in the bleed system is −1.38%, and the average prediction error is −0.8%. This loss model can be used when designing the geometry of a bleed system.

To improve the prediction accuracy of profile loss at low Reynolds number, a typical low-pressure turbine cascade T106D-EIZ was selected to numerically investigate the effect of Reynolds number on turbine cascade flow. A detailed analysis of profile loss was performed and a profile loss model considering the low-Re effect was developed. Results showed that the incidence angle has a great effect on the inlet and outlet Mach number at low Reynolds number, and the variation of inlet and outlet Mach number further affects the blade profile loss. A correction factor was introduced to consider the effect of incidence angle and Mach number on the profile loss. The profile loss coefficient and stalling incidence angle were both extended to lower Reynolds number based on the numerical results. A Smart Through Flow Analysis Program (STFAP) was developed using the finite volume method to solve the circumferentially averaged Euler equations of S2 surface. Aerodynamic performance of E3 5-stage low-pressure turbine was predicted by STFAP coupled with low-Re profile loss model. Compared with K-O model, the prediction accuracy of efficiency of low-pressure turbine last stage is improved by nearly 1.1 percentage points when the 5-stage low-pressure turbine is in a low Reynolds number state.

The ingestion of ice crystals in aero-engine will cause engine surge, flameout, thrust loss, and even in-flight shutdown in the extreme cases, which seriously endanger the flight safety. In order to quantitatively investigate the ice crystal melting characteristic in the compressor, a method based on the compressor mean line flow was developed and validated. Results showed that the wet-bulb temperature increases as the temperature offset increases. The increase in temperature offset or decrease in particle size result in earlier or faster melting of the ice crystals in the low-pressure compressor. The rate of increase in melting ratio decreases with the increase of ice water content at the descent condition. The ambient temperature and ice crystal property are both the important factors affecting the icing risk in the compressor. Higher ambient temperature, smaller particle size or higher ice water content can increase the icing risk in the low-pressure compressor.