Heat Transfer Correction Methods for Turbocharger Performance Measurements

Abstract

Turbocharger performance maps used for the matching process with a combustion engine are measured on test benches which do not exhibit the same boundary conditions as the engine. However, these maps are used in engine simulations, ignoring that the compressor and turbine aerodynamic performance is rated on the basis of quantities which were measured at positions which do not coincide with the respective system boundaries of the turbomachinery. In the operating range of low to mid engine speeds, the ratio between the heat flux and the work done by the turbine and the compressor is much greater than at high speeds where heat transfer phenomena on the compressor side can usually be neglected. Heat losses on the turbine side must be taken into account even at higher shaft speeds when dealing with isentropic turbine efficiencies. Based on an extensive experimental investigation, a one-dimensional heat transfer model is developed. The compressor and turbine side are treated individually and divided into sections of inlet, wheel, outlet, diffuser, and volute. The model demonstrates the capability to properly account for the impact of heat transfer, and thereby improves the predictive accuracy of temperatures relevant for the matching process.

Turbo-assisted direct solar air heater for medium temperature industrial processes using Linear Fresnel Collectors. Assessment on daily and yearly basis

“…[96] stated that a heat fluxes model is needed in both cases if good predictions are demanded and reported several recent works on heat transfer phenomena in turbochargers. [97] recognized that in the low and medium rotating speed regimes, the specific work transfer is small, making heat transfer more relevant, being this attributed to low mass flow rates and pressure ratios.…”

“…Bohn and Heuer [98] and [99] developed a detailed 1D numerical model of heat fluxes besides evaluating them through an experimental analysis. A 1D heat transfer model was also proposed by [96] and [97]. [100] experimentally investigated the heat transfer in a turbocharger test bench.…”

A review of heat transfer in turbochargers

“…The vice versa is also true and useful. Thus an enormous literature [41] exists that involves developing correction models that improve the accuracy of performance maps, for compressor [40] and turbine [42].…”

Measurement, Simulation, and 1D-Modeling of Turbocharger Radial Turbines at Design and Extreme Off-Design Conditions

“…Additionally, it is difficult to compare maps from different suppliers because they consider different boundary conditions, which can affects the internal and external heat transfer. Like shown by Serrano et al [39,40] and Schinnerl et al [41] heat fluxes influence in particular the efficiency of small sized geometries. Furthermore, even when measuring under quasi-adiabatic conditions internal 2.…”