Effects of Tip Clearance Size on Energy Performance and Pressure Fluctuation of a Tidal Propeller Turbine SCIE SCOPUS

Cited 6 time in WEB OF SCIENCE Cited 7 time in Scopus
Title
Effects of Tip Clearance Size on Energy Performance and Pressure Fluctuation of a Tidal Propeller Turbine
Author(s)
Tran, Bao Ngoc; Jeong, Haechang; Kim, Jun-Ho; Park, Jin Soon; Yang, Changjo
Publication Year
2020-08
Abstract
Unavoidable tip clearance between blade tip and casing shroud plays an important role in the performance and characteristics of a tidal propeller turbine. In this work, the tip-leakage vortex (TLV) induced in the end-wall region was numerically illustrated by using the shear-stress transport (SST) k-omega turbulence model at various flow conditions and different tip-clearance sizes (TCSs). The swirling strength criterion was employed to visualize the tip-leakage vortex trajectory and investigate vortex evolution according to clearance size change. Although TLV occurs in both design and off-design conditions, vortex intensity develops strongly under excess flow rate with increased tip gap. The extreme influence of TCS on the turbine's generated power and efficiency was predicted in steady simulations for four TCS cases, namely, delta = 0%, 0.25%, 0.5%, and 0.75%. With the extension of the tip gap, turbine performance was drastically reduced because of vigorous turbulent leakage flow combined with considerable volumetric loss. The effect of TCS on pressure fluctuation intensity were also explored on the basis of the transient simulation statistic. Maximal pressure variation amplitude and dominant frequency were presented in spectrum analysis utilizing fast Fourier transform.
ISSN
1996-1073
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/32920
DOI
10.3390/en13164055
Bibliographic Citation
ENERGIES, v.13, no.16, 2020
Publisher
MDPI
Subject
LEAKAGE VORTEX; FLOW; TURBULENCE; MECHANISMS; FAN
Keywords
computational fluid dynamics (CFD); propeller turbine; tip-clearance size (TCS); tip-leakage vortex (TLV); pressure fluctuation
Type
Article
Document Type
Article
Publisher
MDPI
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