Browsing by Author "Lian, Sin-Hong"

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A mixed convection in a reciprocating Pi shape channel with opposite direction of gravity and inlet cooling fluids
(2009-04-01)
Fu, Wu-Shung
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Lian, Sin-Hong
;
Lai, Yu-Chih
;
機械工程學系
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Department of Mechanical Engineering
A numerical study is executed to investigate heat transfer mechanisms of a reciprocating channel cooled by fluids. The problem of the reciprocating piston is a moving boundary problem, and the Finite Element Method and arbitrary Largragian-Eulerian Kinematics method are then utilized. Due to the high temperature of the channel, a mixed convection is taken into consideration for simulating a more realistic situation. Directions of inlet cooling fluids and gravity are opposite. Concerning important parameters of the Reynolds number and Grashof number, reciprocating frequency and amplitude are examined. Thermal stratification layers which are found firmly on the top surface are deeply dependent on the magnitude of Gr/Re(2) ratio which directly affects the heat transfer mechanisms.
An experimental investigation of a mixed convection in a (sic) shape channel subject to a reciprocating motion
(2009-07-01)
Fu, Wu-Shung
;
Lian, Sin-Hong
;
Lin, Ching-Lun
;
Yang, Chung-Lin
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機械工程學系
An experimental work is conducted to study heat transfer phenomena of a mixed convection in a (sic) shape channel which is subject to a reciprocating motion. Simultaneously, a numerical calculation is executed to validate the experimental results auxiliarily. Parameters of Reynolds number, frequency and amplitude are considered. The results show that enhancement of heat transfer rate caused by the reciprocating motion is remarkable. Due to the impingement of cooling fluids, the heat transfer rate of the front heat region is still superior to those of the middle and back heat regions. The phenomena of this object are very complicated, and the maximum deviation between the experimental and numerical results is not over 25%. (C) 2009 Elsevier Ltd. All rights reserved.
An investigation of a mixed convection in a boolean OR shape channel moving with a reciprocating motion
(2009-11-01)
Fu, Wu-Shung
;
Lian, Sin-Hong
;
Lai, Yu-Chih
;
機械工程學系
;
Department of Mechanical Engineering
This study focuses on utilizing numerical calculation to investigate the heat transfer mechanisms in a shape reciprocating channel system comprised of a horizontal channel at the bottom and vertical channels on both left and right sides. The issue is considered one kind of moving boundary problems and the finite element and Arbitrary Lagrangian-Eulerian (ALE) kinematic methods can be applied to this study. Due to the high temperature at the bottom surface of the horizontal channel and the direction of inlet cooling fluids in the same direction of the gravity, the heat transfer mechanisms induced by the mixed convection flow become extremely complex. The results show that thermal layers near the heat surface are disturbed drastically and the effect of reciprocating motion upon the heat transfer mechanisms strongly depends on a relationship between Reynolds and Grashof numbers. (C) 2009 Elsevier Ltd. All rights reserved.
An investigation of heat transfer of a reciprocating piston
(2006-11-01)
Fu, Wu-Shung
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Lian, Sin-Hong
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Hao, Liao-Ying
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機械工程學系
;
Department of Mechanical Engineering
A numerical simulation of a reciprocating piston cooled by fluid is performed to investigate effects of frequency, amplitude and Reynolds number on heat transfer rate of the piston. For facilitating the analyses, the model of the reciprocating piston is replaced by a "Pi" shape cooling channel. This subject belongs to a kind of moving boundary problems, and the Finite Element Method and arbitrary Lagragian-Eulerian Kinematics description method are then utilized. The heat transfer mechanisms affected by the main parameters of frequency, amplitude and Reynolds number are discussed in detail. The results show that the heat transfer mechanisms influenced by the frequency are more remarkable than those influenced by the amplitude and Reynolds number. Besides, the larger the above three parameters are, the apparent enhancements of heat transfer are usually obtained. (c) 2006 Elsevier Ltd. All rights reserved.