Turbocharged engines are an industrial standard in many applications, from automotive to energy production. Depending on the application, however, the technical requirements for the turbocharging unit are quite different. While in automotive applications the operating range is wide and high efficiency has to be ensured also in transitory phases, in stationary power production the matching between the turbocharger and the engine can be optimized at a specific operating point. This, in turn, may allow the designer to push forward a finer optimization of the turbocharger to maximize the aerodynamic efficiency. On the other hand, one should also bear in mind that the turbocharger is not indeed an isolated turbomachine, but it is in fluid dynamic connection with the engine itself. As a result, modifying its performance implies a change of the engine operating conditions and, in turn, of the boundary conditions the turbocharger itself has to work with.Moving from this background, the present study reports the results of a joint research activity between academia and industry to evaluate how much a dedicated optimization of a turbocharger unit can improve the overall performance of an engine for stationary power production. The optimization has been applied to an existing, state-of-the-art turbocharger.In particular, an integrated methodology has been developed, in which the aerodynamic optimization of the compressor, the turbine and the static parts has been carried out by means of a huge number of high fidelity CFD simulations, while a 1D model of the engine as a whole has been made by means of the GTPower software. An iterative procedure has been established as discussed above, to maximize the overall system efficiency at a fixed operating point in terms of engine speed and load.The study shows how notable aerodynamic improvements can be reached on turbocharger aerodynamics even if starting from “high quality” market products, thanks to the fact that the rangeability can be narrowed. Efficiency increases of 2.4% and of 3.4% have been reached for the compressor and the turbine, respectively. On the other hand, it is shown how this reflects into moderate overall engine improvements (+0.5%), which however are not negligible in case of engine for stationary power production.

Aerodynamic Optimization of a Turbocharger Unit Based on the Overall Efficiency Enhancement of an Internal Combustion Engine for Stationary Power Production

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

Turbo Expo 2021

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