A throughflow model based on the time-marching finite volume approach is described in this paper. The governing equations are derived by circumferentially averaging the three-dimensional Navier-Stokes equations neglecting the circumferentially non-uniform and viscous terms. An inviscid blade force model similar to the Large-particle method is derived. The viscous blade force has been modeled by the distributed loss model. The convective fluxes of the governing equation are discretized with the Edward's low-diffusion flux-splitting (LDFSS) scheme. And a point-iterative Symmetric Gauss-Seidel (SGS) scheme is used in the temporal discretization. The throughflow model has been applied to the NASA Rotor 67 and a high-load transonic fan stage ATS-2. The reasonable good agreements with the experiments and the 3D viscous computations show the potential of the method.

This paper presents the design of a highly loaded transonic two-stage fan using several advanced three-dimensional blading techniques including forward sweep and “hub bending” in rotors and several bowed configurations in stators. The effects of these blading techniques on the performance of the highly loaded transonic two-stage fan were investigated on the basis of three-dimensional Navier-Stokes predictions. The results indicate that forward sweep has insignificant impact on the total pressure ratio and adiabatic efficiency of the fan. The throttling range of the fan is found to be improved by forward sweep because the shock in the forward swept rotor is expelled later upstream to the leading edge than that in the unswept one. Hub bending design technique increases the efficiency in the hub region of R1 due to the reduction of the low momentum zone in the hub region near the trailing edge. The stator vane design has a pronounced impact on the performance of the fan. The total pressure ratio, adiabatic efficiency, and stall margin of the schemes with the bowed vanes are increased significantly compared to the scheme with the straight vanes. The large corner stall in the straight S1 vane is reduced effectively by the bowed S1 vanes. Moreover, the strong corner stall in the straight S2 vane is fully eliminated by the bowed S2 vanes. Among the bowed vane schemes, the scheme with positive bowed (P. B.) hub and negative bowed (N. B.) tip vanes has the best efficiency and stall margin performances thanks to the superiority of the performance over the midspan regions of the bowed vanes.

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A fast computational method of the aerodynamic characteristics of fan and booster with inlet distortion is developed in this paper. This method is based on a time-marching throughflow model, and the governing equations are circumferentially averaged Navier-Stokes equations. A model of distributed inviscid blade force and viscid blade force is adopted to reproduce the flow deflection and loss. The deviation angle and loss parameters are interpolated from a database which is extracted from 3-D simulation results of compressor with uniform inlet. After a validation case is performed, the aerodynamical performances of a multistage fan and booster with inlet radial and circumferential distortion are computed. The results show the predictive ability of this method, and the acceptable computational time cost indicates the future application potential of this method during the design stage of a new turbomachinery.

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