Unsteady performance of a mixed-flow turbine with nozzled twin-entry volute confronted by pulsating incoming flow
File(s)
Accepted version
Author(s)
Xue, Yingxian
Yang, Mingyang
Martinez-Botas, Ricardo F
Yang, Bijie
Deng, Kangyao
Type
Journal Article
Abstract
Turbine with twin-entry volute has advantage of utilising energy from pulsatile exhaust gas and improving low-speed torque of an internal combustion engine. This paper investigates unsteady performance of a mixed flow turbine with nozzled twin-entry volute confronted by pulsatile incoming flow. The turbine performance at pulsating conditions with different Strouhal numbers (St) is studied via experimentally validated numerical method. Results show that the unsteadiness of turbine performance is enhanced as Strouhal number increases. In particular, the cycle-average efficiency at St = 0.522 is about 3.4% higher than that of quasi-steady condition (St = 0). Instantaneous loss breakdown of the turbine shows that the entropy generation rate of turbine components reduces evidently at pulsating conditions as Strouhal number increases, especially for the nozzle. Specifically, the cycle-averaged reduction of the loss in the nozzle is 37.3% at St = 0.522 compared with that of St = 0. The flow analysis shows that secondary flow which contributes to the majority of loss in the nozzle, including flow separation, horseshoe vortex, and reversed flow near the leading edge, are notably alleviated as Strouhal number increases. The alleviation of the flow structures are resulted from two reasons: one is that the flow distortion at the nozzle inlet is evidently depressed by the pulsating conditions, the other is that the inertia of the low momentum flow in the nozzle damps flow evolution at pulsating incoming flow. Consequently, the loss is reduced and the turbine performance is benefited by the pulsating inflows.
Date Issued
2019-12-01
Date Acceptance
2019-10-14
Citation
Aerospace Science and Technology, 2019, 95, pp.1-13
ISSN
1270-9638
Publisher
Elsevier
Start Page
1
End Page
13
Journal / Book Title
Aerospace Science and Technology
Volume
95
Copyright Statement
© 2019 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000503313200065&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Engineering, Aerospace
Engineering
Turbine
Twin-entry volute
Pulsating conditions
Unsteady performance
RADIAL TURBINE
Publication Status
Published
Coverage Spatial
Xian, PEOPLES R CHINA
Article Number
UNSP 105485
Date Publish Online
2019-10-18