Time-Marching Throughflow Analysis of Centrifugal Compressors with Boundary Conditions Based on Newton’s Method

Abstract

The meridional distribution of the flow parameters inside the centrifugal compressor is of great importance to its overall performance, as well as its matching performance under a thermal cycle. A time-marching throughflow method for the off-design performance analysis of the centrifugal compressor is described. The method is based on the strictly conservative throughflow-governing equations, and an improved method of boundary-condition enforcement is developed based on Newton’s method to achieve a robust and fast throughflow simulation. An inviscid blade force model was adopted to obtain the flow deflection inside the blade passage. Empirical loss models were integrated into the throughflow model to simulate the viscous force effects in the real three-dimensional flow. Two test cases are presented to validate the throughflow method by comparisons with the experimental data or CFD results, including the NASA low-speed centrifugal compressor (LSCC) and the Allison high-performance centrifugal compressor (HPCC). The simulation indicated that the developed enforcement method for the inlet and outlet boundary conditions significantly improves the computational robustness. For both the LSCC and HPCC cases, reasonable flow-parameter distribution was obtained and accurate overall characteristics were also predicted under the off-design conditions. The results indicated that the developed time-marching throughflow method is effective and efficient for the performance analysis of centrifugal compressors.

Throughflow inverse design of a transonic fan stage based on CFD method

“…Since the general theory of three-dimensional flow is proposed in the 1950s [1], researchers worldwide have developed various throughflow methods, including the stream function method [2], streamline curvature method [3], and CFD (Computational Fluid Dynamics)-based throughflow method [4][5][6][7][8][9][10][11]. Among them, the stream function method and the streamline curvature method have the advantages of simple solution, fast and stable calculation, etc.…”

Power Balance Strategies in Steady-State Simulation of the Micro Gas Turbine Engine by Component-Coupled 3D CFD Method

“…In low-dimensional simulations, such as through-flow simulations, the turbulence models used in CFD cannot accurately simulate viscous losses for the dimensional reduction. Therefore, the empirical loss models or viscous force models need to be supplemented for these methods [17][18][19]. Leaving the difficulty of establishing this kind of model aside, the low-dimensional simulation method with nonphysical treatment of the components' interfaces or boundaries cannot reflect the coupling relationship of the components.…”