Effect of Tip Clearance on the Thermal and Hydrodynamic Performance of a Shrouded Pin Fin Array
01 Dec 2003-Journal of Heat Transfer-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 125, Iss: 6, pp 999-1006
TL;DR: In this article, the effect of tip clearance on a liquid cooled array of shrouded pins fins was examined and empirical correlations were proposed for the increase in overall heat transfer rate and adiribatic pressure drop across the array.
Abstract: The effect of introducing tip clearance to a liquid cooled array of shrouded pins fins is examined Three arrays of height to diameter ratio ranging from 05 to 11 were evaluated experimentally The arrays were exposed to a uniform heal flux of 002 to 026 W/mm 2 and cooled with water through a nominal Reynolds number range of 200 to 10000 Tip clearance of 0 to 25% of pin height was assessed Mean heat transfer rates and adiribatic pressure drop across the array were determined and empirical correlations are proposed The introduction of clearance was seen to increase overall heat transfer in some cases
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Cites background from "Effect of Tip Clearance on the Ther..."
...As noted by Moores and Joshi [ 13 ], intermediate size shrouded pin fin (1/2 < L/D <8 ) heat sinks are primarily encountered in applications concerning turbine blade or vane cooling, whereas short pins are commonly found in compact heat exchangers [14]....
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Journal Article•
7,568 citations
TL;DR: In this paper, the authors discuss the heat transfer and the hydraulic resistance of single tubes, and the banks of tubes of various arrangements in flows of gases and viscous liquids, and highlight the influence of the physical properties of fluids on heat transfer.
Abstract: Publisher Summary This chapter discusses the heat transfer and the hydraulic resistance of single tubes, and the banks of tubes of various arrangements in flows of gases and viscous liquids. The focus is on the important problems of the heat transfer and the hydraulic resistance of tubes, in particular with the heat transfer of single tubes, banks of tubes, and systems of tubes in crossflow. The chapter also highlights the influence of the physical properties of fluids on heat transfer. Extensive experimental data will be analyzed and will include investigations of banks of tubes of various arrangements, and a single tube in crossflow in the range of Prandtl number from 0.7 to 500 and that of Reynolds number from 1 to 2xl0 6 .
1,181 citations
TL;DR: Transfert de chaleur dans une ailette munie d'elements en quinconce en particulier en vue d'applications au refroidissement des turbines.
Abstract: Transfert de chaleur dans une ailette munie d'elements en quinconce en particulier en vue d'applications au refroidissement des turbines. Article de synthese
193 citations
Book•
01 Jan 1995
TL;DR: In this article, the authors present an algorithm for Finned array assembly, which is based on linear transformations with singular fins and spines and single elements, and a general array method with reciprocity and node analysis.
Abstract: Linear Transformations. Elements of the Linear Transformations. Singular Fins and Spines and Single Elements. Algorithms for Finned Array Assembly. Examples of Finned Array Analysis. Reciprocity and Node Analysis. A General Array Method. Convective Optimizations. Heat Transfer-Parallel Plate Heat Sinks. References. Appendices. Indexes.
153 citations
TL;DR: In this article, a mass transfer analogy based on the naphthalene sublimation technique was used to reveal the individual heat transfer contributions from pins and endwalls with the entire wetted surface thermally active.
Abstract: Short pin-fin arrays are often used for cooling turbine airfoils, particularly near the trailing edge. An accurate heat transfer estimation from a pin-fin array should account for the total heat transfer over the entire wetted surface, which includes the pin surfaces and uncovered endwalls. One design question frequently raised is the actual magnitudes of heat transfer coefficients on both pins and endwalls. Results from earlier studies have led to different and often contradicting conclusions. This variation, in part, is caused by imperfect or unrealistic thermal boundary conditions prescribed in the individual test models. Either pins or endwalls, but generally not both, were heated in those previous studies. Using a mass transfer analogy based on the naphthalene sublimation technique, the present experiment is capable of revealing the individual heat transfer contributions from pins and endwalls with the entire wetted surface thermally active. The particular pin-fin geometry investigated, S/D = X/D = 2.5 and H/D = 1.0, is considered to be one of the optimal array arrangement for turbine airfoil cooling. Both inline and staggered arrays with the identical geometric parameters are studied for 5000 < Re < 25,000. The present results reveal that the general trends of the row-resolved heat transfer coefficients on either pins or endwalls are somewhat insensitive to the nature of thermal boundary conditions prescribed on the test surface. However, the actual magnitudes of heat transfer coefficients can be substantially different, due to variations in the flow bulk temperature. The present study also concludes that the pins have consistently 10 to 20 percent higher heat transfer coefficient than the endwalls. However, such a difference in heat transfer coefficient imposes very insignificant influence on the overall array-averagea heat transfer, since the wetted area of the uncovered endwalls is nearly four times greater than that of the pins.
141 citations