A one-dimensional unsteady performance model for turbocharger turbines

Abstract

With the widespread application of pulse turbochargers in internal combustion engines, steady or quasi-steady turbine models are no longer qualified for on-engine turbine performance prediction. Pulsatile flow condition caused by the reciprocating nature of the engine results in strong unsteadiness across the turbocharger turbine, which makes the turbine performance departing from that under steady or quasi-steady conditions. Modelling turbocharger turbine through a one-dimensional (1D) method is an important approach to simulate the unsteady performance of the turbine.In this paper, a 1D performance model of turbocharger turbines is presented. The model solves the turbine volute flow with 1D viscous equations, with volute curvature and circumferentially continuously flow exiting at volute outlet considered. The circumferential flow non-uniformity at volute outlet is preserved. The turbine rotor is modeled with multiple meanline models. The model was used to simulate the performance of a mixed-flow turbine and validated by the experimental data. Results show that the performance predictions are in good agreement with the experimental data. Flow parameters at internal points of the turbine predicted by the 1D model were compared with three-dimensional unsteady simulation results and reasonable agreement was observed, which demonstrates the ability of the 1D model in capturing the pulse propagation.