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Design optimisation of a unidirectional centrifugal radial-air-turbine for application in OWC wave energy converters

Citation

Ansarifard, N and Fleming, A and Henderson, A and Kianejad, SS and Chai, S, Design optimisation of a unidirectional centrifugal radial-air-turbine for application in OWC wave energy converters, Energies, 12, (14) Article 2791. ISSN 1996-1073 (2019) [Refereed Article]


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Copyright 2019 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

Abstract

Research on employing unidirectional air turbines for oscillating water columns (OWC) has received much attention in the last few years. Most unidirectional turbine topologies considered to date use axial flow unidirectional turbines. The radial turbine offers an alternative with increased resistance to backflow. However, in general, the efficiency of radial turbines is lower than axial turbines. This study describes a computational fluid dynamics (CFD)-based design optimisation of an outflow radial turbine for the intended application in an OWC system configured to enable primarily unidirectional flow through the turbine. The rotor blade geometry is parametrically described in addition to other turbine components. The central composite design (CCD) and genetic algorithm were used to explore an optimum design of a centrifugal radial turbine for a maximum total-to-static efficiency. Seven computer aided design (CAD) parameters were investigated as the design variables, and the optimum turbine design was identified in a population of 79 design points. The optimum outflow turbine was found to have a peak steady-state efficiency of 72%, and the leading-edge angle, guide vane angle, trailing edge angle, and the chord length were found to have the highest sensitivity. Compared to an inflow radial turbine, the geometrical features of the outflow turbine permit higher absolute velocities of the flow at the rotor entrance and increase the dynamic pressure changes across the rotor. Therefore, the optimised outflow radial turbine can obtain acceptable rotor energy transfer despite having a negative centrifugal energy transfer term.

Item Details

Item Type:Refereed Article
Keywords:outflow radial air turbine, optimization, efficiency maximization, computational fluid dynamics (CFD), wave energy conversion, vented OWC
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Marine Engineering
Objective Division:Environment
Objective Group:Other Environment
Objective Field:Marine Oceanic Processes (excl. climate related)
UTAS Author:Ansarifard, N (Ms Nazanin Ansarifard)
UTAS Author:Fleming, A (Dr Alan Fleming)
UTAS Author:Henderson, A (Dr Alan Henderson)
UTAS Author:Kianejad, SS (Mr Seyedsadreddin Kianejadtejenaki)
UTAS Author:Chai, S (Professor Shuhong Chai)
ID Code:134054
Year Published:2019
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2019-07-24
Last Modified:2019-08-05
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