EXPERIMENTAL INVESTIGATION ON THE INFLUENCE OF CASING RELATIVE MOTION ON HEAT TRANSFER CHARACTERISTICS OF THE SQUEALER TIP.

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Bibliographic Details
Title:	EXPERIMENTAL INVESTIGATION ON THE INFLUENCE OF CASING RELATIVE MOTION ON HEAT TRANSFER CHARACTERISTICS OF THE SQUEALER TIP.
Authors:	LI, Ziqiang¹, CHEN, Pingting¹ cpt09@nuaa.edu.cn, SHAO, Yuming¹, HAN, Feng¹
Source:	Thermal Science. 2025, Vol. 29 Issue 6B, p4891-4903. 13p.
Subjects:	Heat transfer, Relative motion, Mathematical models, Turbine blades, Thermometry, Fluid flow
Abstract:	This study develops an experimental set-up 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 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%-7.4%, confirming that smaller tip clearance height favor heat transfer coefficient reduction. Higher Reynolds number increased the heat transfer coefficient, though the growth rate diminished progressively with increasing Reynolds number. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	This study develops an experimental set-up 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 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%-7.4%, confirming that smaller tip clearance height favor heat transfer coefficient reduction. Higher Reynolds number increased the heat transfer coefficient, though the growth rate diminished progressively with increasing Reynolds number. [ABSTRACT FROM AUTHOR]
ISSN:	03549836
DOI:	10.2298/TSCI250313115L