Fast 2-D Heat Transfer Model for Computing Internal Temperatures in Automotive Turbochargers 2017-01-0513

The growing concerns about emissions in internal combustion engines, makes necessary a good prediction of the after-treatment inlet temperature in fast one-dimensional engine simulation codes. Different simple models have been developed during the last years which improve the prediction of the turbocharger heat transfer phenomena. Although these models produce good results when computing the turbine outlet temperature, those models focus on the axial heat transfer paths and lack the capability of producing detailed results about the internal thermal behavior of the turbocharger. In this work, a new version of heat transfer model for automotive turbochargers is presented. This model discretizes the turbocharger in both the radial and axial directions, and computes the heat transfer and temperature at different parts of the machine. Aiming for a low computational cost, it was designed to be compatible with fast one-dimensional engine simulations as a replacement of previous models [1]. The paper deals with the description of the radial heat transfer model, tuning and validation for not water cooled turbocharger. The paper describes the heat transfer equations that serve as base for modeling other turbochargers by modifying geometry, material, and boundary conditions with the advantage of computing the oil temperature inside the turbocharger central housing, lubrication channels, and maximum level of temperature at different points in the bearing system, with the aim of reduce experimental tasks.

The model results can be use practically to study heat exchanges occurring inside and the effects on the turbocharger performance. It will allow to evaluate thermal damage done to the system itself, guidance for researchers on the development of effective procedures and tools to cope with the technological exigencies in the optimum performance of the turbocharging system. As well as influences on the working fluid temperatures which leads oil coke formation, that can affect the performance of the engine[2].