THERMAL SCIENCE
International Scientific Journal
Thermal Science - Online First
online first only
Experimental investigation on the influence of casing relative motion on heat transfer characteristics of the squealer tip
ABSTRACT
This study develops an experimental setup for turbine blade-casing relative motion investigation and employing transient liquid crystal thermometry for precise thermal measurements, and systematically examines the coupled effects of tip clearance height with squealer rim dimensions (height and width) and Reynolds number (Re) on heat transfer characteristics of the squealer tip under the casing relative motion. The experimental results were fitted with empirical formulas.The results demonstrated that the relative motion between the turbine blade and the casing altered the heat transfer distribution while reducing the heat transfer coefficient at the blade tip. For instance, increasing the casing velocity from 0 m/s to 30 m/s decreased the area-averaged heat transfer coefficient at the squealer tip by 10.93%, with a more pronounced reduction of 17.19% observed at the squealer rim top surface. Under casing relative motion, increasing the height and width of the squealer rim significantly reduces heat transfer coefficient and enhances the uniformity of the heat transfer distribution. For instance, increasing the squealer rim height from 1.5% to 5.0% of the blade height reduced the area-averaged heat transfer coefficient by approximately 20.0%, while expanding the squealer rim width from 1.0% to 4.0% of the blade height decreased the area-averaged heat transfer coefficient by 10.64%. Increasing the tip clearance height from 1.0% to 3.0% of the blade height elevated the heat transfer coefficient by 5.5% to 7.4%, confirming that smaller tip clearance height favor heat transfer coefficient reduction. Higher Re increased the heat transfer coefficient, though the growth rate diminished progressively with increasing Re.
KEYWORDS
PAPER SUBMITTED: 2025-03-13
PAPER REVISED: 2025-04-03
PAPER ACCEPTED: 2025-05-15
PUBLISHED ONLINE: 2025-07-05
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