Evaluation of different heat transfer conditions on an automotive turbocharger

Abstract

This paper presents a combination of theoretical and experimental investigations for determining the main heat fluxes within a turbocharger. These investigations consider several engine speeds and loads as well as different methods of conduction, convection, and radiation heat transfer on the turbocharger. A one-dimensional heat transfer model of the turbocharger has been developed in combination with simulation of a turbocharged engine that includes the heat transfer of the turbocharger. Both the heat transfer model and the simulation were validated against experimental measurements. Various methods were compared for calculating heat transfer from the external surfaces of the turbocharger, and one new method was suggested.The effects of different heat transfer conditions were studied on the heat fluxes of the turbocharger using experimental techniques. The different heat transfer conditions on the turbocharger created dissimilar temperature gradients across the turbocharger. The results show that changing the convection heat transfer condition around the turbocharger affects the heat fluxes more noticeably than changing the radiation and conduction heat transfer conditions. Moreover, the internal heat transfers from the turbine to the bearing housing and from the bearing housing to the compressor are significant, but there is an order of magnitude difference between these heat transfer rates.

Experimental validation of a quasi-two-dimensional radial turbine model

“…The results of including a heat transfer model to determine internal heat flows has been investigated by several authors, such as in the works by Olmeda et al 12 or Serrano et al 13 . These models can even be used to obtain information that is difficult to measure in an experiment, such as the difference heat flow paths, as in the work by Aghaali et al 14 . Friction losses models as the one developed by Serrano et al 15 or Marelli et al 16 have been also coupled with one-dimensional gas dynamics codes so the mechanical efficiency can be computed in time marching simulations, as shown in 17 .…”

Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes

“…The engine test bench experiments represent the closest approximation to real vehicle operation conditions. An important effort has been made by some authors [7] in analysing different heat transfer conditions in the turbocharger on engine operation. These studies conclude that the importance of heat transfer phenomena in the overall power exchange inside the 20 turbocharger can be significant at low and medium turbocharger speeds.…”

General Procedure for the Determination of Heat Transfer Properties in Small Automotive Turbochargers

“…However, such approach cannot be adapted to whole engine simulations due to computational costs, so it must be coupled to 1D simulation codes [16]. Other studies [17,18] have been centred in considering turbocharger heat transfer in a whole 1D engine model but a lot of tests on engine bench are needed for this procedure.…”