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Abstract:
In this paper, under the GE-E3 turbine stage condition, the effect of the casing step on the heat transfer performance is obtained by solving three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations. The heat transfer characteristics predicted by standard k-ω model are consistent with the experimental data. The simulation results reveal that, the tip heat transfer coefficient decreases and the area of the high heat transfer region is reduced by introducing the casing step structure. Compare to the baseline case, when the casing step height is 1%, 2% and 3% of the blade height, the area-average heat transfer coefficient at the blade tip decreases by 6.1%, 6.7% and 7.0%, respectively. The introduction of casing step structure can eliminate the swirling strength of Scraping Vortex (SV), thus weaken the reattachment of tip leakage flow on the cavity bottom. Under the step vortex effect, the mainstream from the tip pressure side entering the tip cavity is reduced and replaced by entering from the tip suction side. Because of the lower pressure difference between the tip suction side and the tip clearance, the swirling strength of SV is decreased. Arranging a casing step with the same size as the tip clearance upstream the blade can reduce the tip heat transfer performance to the greatest level. The introduction of casing step structure also has a negative effect on the output power and efficiency of the turbine, it is necessary to balance the aerodynamic and heat transfer of the turbine in order to achieve the optimal results. © 2021 Elsevier Masson SAS
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Source :
International Journal of Thermal Sciences
ISSN: 1290-0729
Year: 2021
Volume: 174
3 . 4 7 6
JCR@2019
ESI Discipline: ENGINEERING;
ESI HC Threshold:30
Cited Count:
WoS CC Cited Count: 1
SCOPUS Cited Count: 9
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 15