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Unsteady Simulation of Six-Inlet Pulsed Flow Turbocharger Turbine
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
The turbochargers are driven by unsteady, pulsating flow. Such flow is generated by exhaust phase of an internal combustion engine. A lot of turbocharger simulations are done during steady-state operation. Such simulations are favorable for turbocharger optimization at certain operating point. However, the frequency and amplitude of exhaust pulses can heavily influence turbine performance. This paper presents results of 3D simulations of six-inlet turbocharger turbine, under pulsating operation with moving mesh approach. One of the key point of interests was separation of pressure pulses from six exhaust pipes during engine operation. The leakage between exhaust pipes was analyzed at each time step at different turbine speed. Another key point was turbine response during pulsating flow at different rotor speed. Parameter such as turbine total-static efficiency under single pressure pulse was investigated. Also, exhaust pipes were studied to check its filling-emptying behavior. Article is divided in three parts. First part contains in-depth literature review concerning turbochargers operation under pulsating flow. Second one contains description of the problem and computational approach. For the purpose of the study, a 3D transient simulation was considered. Last part contains results and conclusions. The results showed, that the highest efficiency was achieved for turbine speed of 60 000 rpm. However, deeper study is needed under higher turbine speeds. The most important fact, is that six-inlet turbine housing not only separates exhaust pulses from each cylinder, but also prevents leakage from one exhaust pipe to another. Such solution will be used in exhaust system of newly-designed Opposed-Piston engine.