Universiti Teknologi Malaysia Institutional Repository

Influence of pulsating flow frequencies towards the flow angle distributions of an automotive turbocharger mixed-flow turbine

Padzillah, Muhamad Hasbullah and Rajoo, Srithar and Mingyang, Yang and Martines-Botas, Ricardo (2015) Influence of pulsating flow frequencies towards the flow angle distributions of an automotive turbocharger mixed-flow turbine. Energy Conversion and Management, 98 (1). pp. 449-462. ISSN 0196-8904

Full text not available from this repository.

Official URL: http://dx.doi.org/10.1016/j.enconman.2015.03.028

Abstract

This paper aims to provide a detailed understanding of the flow interaction within the complex geometry of turbine stage coupled with reflection and superposition of the imposed unsteady pressure waves. The defining performance characteristic of a turbomachines is the inlet flow angle at its leading edge, which in most cases limit its optimum operational range. Pulsating flow field, typical to turbocharger turbine due to opening and closing of the exhaust valves, further deteriorates the flow angle distribution around its circumference, hence performance. To investigate this phenomena and how it differs from the steady state equivalent, a fully validated 'cold flow' Computational Fluid Dynamics (CFD) analysis was carried out. For this purpose, 4 unsteady CFD simulations of 20 Hz, 40 Hz, 60 Hz and 80 Hz together with the steady state simulations have been conducted at 30,000 rpm turbine speed. Discussions in this paper aim to provide a better insight on the flow angle behaviour in pulsating flow field. Evidences are shown where flow angle swings over a wide range (300% more than the steady state condition) in pulsating flow field as it propagates through the guide vanes. It was also found that the flow angle fluctuations during pressure drop period is significantly lower as compared to that during pressure increment period by (19°). This work also leads to a recommendation of correction factor in applying quasi-steady assumption of the rotor wheel. Without this correction, the prediction results could lead to underestimation of mass flow parameter up to 8% at high pressure ratio

Item Type:Article
Uncontrolled Keywords:pulsating flow, turbine
Subjects:T Technology > TJ Mechanical engineering and machinery
Divisions:Mechanical Engineering
ID Code:55849
Deposited By: Fazli Masari
Deposited On:06 Oct 2016 06:23
Last Modified:15 Feb 2017 01:00

Repository Staff Only: item control page