Total Pressure Loss Mechanism of Centrifugal Compressors

Xiaoyang Gong,Rui Chen

doi:10.5539/mer.v4n2p45

Abstract

To develop the turbocharger matching system, a compressor model and turbine model need to be developed independently and coupled. This paper describes the construction of the centrifugal compressor model and its validation with the experimental data. The compressor model in this paper uses One-dimensional (1D) thermo-fluid equations to analyse the compressor side of a turbocharger. Under a specified set of turbocharger geometry, atmospheric conditions, rotational speed, and fluid mass flow rate, the model can calculates the static and total temperatures, velocities, static and total pressures, pressure losses, and isentropic efficiencies for each compressor component. Instead of using lumped loss parameters, the compressor model includes established loss models found in the open literature. Not only in the impeller, the losses in the diffuser and the volute are modelled. With the model, it is possible for a parametric study on the effect of each loss mechanism on the performance, and which can aid the designer in justifying design decisions minimising the magnitude of the losses and thus positively influence the overall performance. The compressor model can also be applied to investigate the two stage Turbocharging or Variable Geometry Turbocharger (VGT) in the future.

Highlights

Worldwide regulators are setting stringent fuel economy and emissions standards that are challenging auto manufacturers to create less emission, more fuel efficient passenger cars
This paper describes the construction of the centrifugal compressor model and its validation with the experimental data
This paper aims to bring all potential losses in each component of compressor together to reveal the full total pressure loss mechanism in centrifugal compressor

Summary

Introduction

Worldwide regulators are setting stringent fuel economy and emissions standards that are challenging auto manufacturers to create less emission, more fuel efficient passenger cars. As vehicle manufacturers weigh up the cost-benefits of reaching these incoming targets, analysts agree that one technology in particular - turbocharging will play a central enabling role (Watson & Janota, 1982).While turbodiesels will remain the dominant powertrain, stricter EU regulations on emissions and strong growth in boosted gasoline engines mean that by 2020, around 85% of all new light vehicles in Europe will be turbocharged, in line with demand for smaller, better performing engines (Baines, 2005). A comprehensive prediction technique, which enables the designer to examine the performance of all the individual components within the compressor at the initial design stage, would result in a device designed to its optimum specification (Watson & Janota, 1982). Despite impressive progress in computational fluid dynamics procedures, one-dimensional prediction techniques continue to be the most accurate and the most practical method of predicting the performance of a stage or a component of a stage (Watson & Janota, 1982)

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