Abstract:
|
In the present work a comprehensive study of turbocharger heat transfer phenomena is
discussed, showing their relevance compared to gas enthalpy variations through the turbomachinery.
The study provides an experimental ...[+]
In the present work a comprehensive study of turbocharger heat transfer phenomena is
discussed, showing their relevance compared to gas enthalpy variations through the turbomachinery.
The study provides an experimental methodology to consider the different
heat fluxes in the turbocharger and modeling them by means of a lumped capacitance
heat transfer model (HTM). The input data required for the model are obtained experimentally
by a proper combination of both steady and transient tests. These tests are performed
in different test benches, in which incompressible fluids (oil) and compressible
fluids (gas) are used in a given sequence. The experimental data allows developing heat
transfer correlations for the different turbocharger elements. These correlations take into
account all the possible heat fluxes, discriminating between internal and external heat
transfer. In order to analyze the relative importance of heat transfer phenomena in the
predictability of the turbocharger performance and the different related variables; model
results, in hot and cold conditions, have been compared with those provided by the standard
technique, consisting on using look up maps (LUM) of the turbocharger. The analysis
of these results evidences the highly diabatic operative areas of the turbocharger and it
provides clearly ground rules for using hot or cold turbocharger maps. In addition, paper
discussion advises about using or not aHTM, depending on the turbocharger variables
and the operative conditions that one desires to predict. Paper concludes that an accurate
prediction of gas temperatures at turbine and compressor outlet and of fluid temperatures
at water and oil ports outlet is not always possible without considering heat
transfer phenomena in the turbocharger.
[-]
|