【作者】

Yuri A. Grishin

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 It is important to give the adequate boundaries at the turbine inlet when numerically modelling the one-dimensional simulation task (1D CFD) for unsteady flow in the exhaust system of a TC piston engines. The mostly wide used way is when the turbine characteristics are taken for the turbine reflected exhaust pulses calculation, and these characteristics are obtained on the test bench at stationary conditions. In such cases, the boundaries ratios for numerical calculation are taken only at the one centered section of the turbine inlet. This method may not provide a satisfactory results for the pulse systems calculation in case of the turbines of some particular geometry with or without blades snail nozzle outlet with an extended nozzle cut, which length is equal to the length of the median circle diameter at the entrance to impeller. Since the length of this circle may have a size comparable to the length of an exhaust manifold itself. In this case, it is necessary to consider the distribution of pulses interaction with the impeller over the median circumference diameter. Experience shows that instead of the complicated gradual distribution along the length of the interaction one can use the model when the input to impeller conventionally concentrated in two sections – at the entrance to the cut-off nozzle and at its outlet, with this the inlet to the nozzle cut-off is represented as a tree branch. The numerical calculation of unsteady flow before the first and second cross-sections performed as a continuation of the 1D modelling of exhaust manifold, but considering its constrictor geometry and its losses in the nozzle. The flow calculation in relatively short ports of impeller is performed in a quasi-stationary formulation with the usage of a shock of discontinuity methods. We developed the special method for accounting of the separated flow losses at the high values of the attack angle at the inlet to impeller. Verification of the developed calculation method for interacting pulses was carried out on a special experimental test bench consisting of solitary pulses generator, manifold and the turbine. Relevant calculations performed numerically with the usage of a shock of discontinuity methods (Godunova methods) showed a good agreement with experiments.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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