Experimental Study of Heat Transfer Coefficients on the Plate with Confined Impinging Jet Array

2012 ◽  
Vol 8 (1) ◽  
pp. 643-648
Author(s):  
T. M. Jeng ◽  
S. C. Tzeng ◽  
C. Y. Wu ◽  
C. T. Yeh
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Impinging Jet ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Jet Array

An Experimental Study of Free Corrective Heat Transfer in a Parallelogrammic Enclosure

1983 ◽  
Vol 105 (3) ◽  
pp. 433-439 ◽  
Author(s):  
N. Seki ◽  
S. Fukusako ◽  
A. Yamaguchi
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Nusselt Number ◽  
Correlation Equation ◽  
Transformer Oil ◽  
Experimental Measurements ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Prandtl Numbers ◽  
Rayleigh Numbers

Experimental measurements are presented for free convective heat transfer across a parallelogrammic enclosure with the various tilt angles of parallel upper and lower walls insulated. The experiments covered a range of Rayleigh numbers between 3.4 × 104 and 8.6 × 107, and Prandtl numbers between 0.70 and 480. Those also covered the tilt angles of the parallel insulated walls with respect to the horizontal, φ, of 0, ±25, ±45, ±60, and ±70 deg under an aspect ratio of H/W = 1.44. The fluids used were air, transformer oil, and water. It was found that the heat transfer coefficients for φ = −70 deg were decreased to be about 1/18 times those for φ = 0 deg. Experimental results are given as plots of the Nusselt number versus the Rayleigh number. A correlation equation is given for the Nusselt number, Nu, as a function of φ, Pr, and Ra.

MEMS Impinging-Jet Cooling

2000 ◽  
Author(s):  
Qiao Lin ◽  
Shuyun Wu ◽  
Yin Yuen ◽  
Yu-Chong Tai ◽  
Chin-Ming Ho
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Jet Impingement ◽  
Impinging Jet ◽  
Impinging Jets ◽  
Measured Temperature ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Heat Transfer Coefficients ◽  
Jet Cooling

Abstract This paper presents an experimental investigation on MEMS impinging jets as applied to micro heat exchangers. We have fabricated MEMS single and array jet nozzles using DRIE technology, as well as a MEMS quartz chip providing a simulated hot surface for jet impingement. The quartz chip, with an integrated polysilicon thin-film heater and distributed temperature sensors, offers high spatial resolution in temperature measurement due to the low thermal conductivity of quartz. From measured temperature distributions, heat transfer coefficients are computed for single and array micro impinging jets using finite element analysis. The results from this study for the first time provide extensive data on spatial distributions of micro impinging-jet heat transfer coefficients, and demonstrate the viability of MEMS heat exchangers that use micro impinging jets.

An Experimental Study of Heat Transfer With an Impinging Circular Water Jet

2003 ◽  
Author(s):  
Hao Leng ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Hongbin Min ◽  
G.-X. Wang
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
High Efficiency ◽  
Impinging Jet ◽  
High Heat ◽  
Water Jet ◽  
Back Surface ◽  
High Tech ◽  
High Heat Flux ◽  
Transfer Coefficients

Impinging jet is widely used in both traditional industrial and new high-tech fields. High efficiency heat transfer in impinging jet cooling makes it an important method for heat transfer enhancement, in particular in cooling of electronic devices with high heat density. This paper presents an experimental study of heat transfer by an impinging circular water jet. A Constantan foil with the size of 5 mm × 5 mm was used to simulate a microelectronic chip with heat generated by passing an electrical current through the foil. A high heat flux over 106 W/m2 was achieved. The surface temperature was measured by a thermocouple glued onto the back surface of the foil. Both a free surface jet and a submerged jet were investigated. Effect of the nozzle-to-surface spacing as well as the jet speed at the exit of the nozzle on cooling was examined. By positioning the jet away from the center of the heating foil surface, the radial variation of the heat transfer coefficients over the foil was also investigated. Quantitative heat transfer data have been obtained and analyzed.

Numerical Simulation Study of Impinging Jet Impact Fin Surface on Heat Transfer Characteristics

2013 ◽  
Vol 663 ◽  
pp. 586-591 ◽  
Author(s):  
Li Ming Zhou ◽  
Lei Zhu ◽  
Jing Quan Zhao ◽  
Meng Zheng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermal Resistance ◽  
Jet Impingement ◽  
Impinging Jet ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Transfer Characteristics ◽  
Jet Impact ◽  
Jet Array

Three-dimensional numerical simulation was implemented to analyze the heat transfer characteristics for jet impingement impact fin surface. 60 calculation cases were simulated to investigate the effects of different fin surfaces on heat transfer characteristics, and 12 jet array impingement cases were calculated for comparison. The results shown that the fin shape, the height and the fin arrangement were the critical factors to affect the jet impingement and the best combination were existed in a certain range. The thermal resistance of cylinder fin arranged in order was34.7 percent higher than that of cylinder fin arranged staggered. The thermal resistance of square fin arranged in order was38.9 percent higher than that of square fin arranged staggered .The heat transfer coefficients of impinging jet impact fin surface were better than that of jet array impingement. The fitting correlations on heat transfer of impinging jet impact fin surface were given.

An Experimental Study of Pin Fin Heat Sinks and Determination of End Wall Heat Transfer

2003 ◽  
Author(s):  
Massimiliano Rizzi ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Optimization Methods ◽  
Heat Sinks ◽  
Base Region ◽  
Transfer Coefficients ◽  
Media Type ◽  
Pin Fin ◽  
Heat Transfer Coefficients

An experimental study of a pin fin heat sink was carried out in support of the development of heat sink optimization methods requiring more detailed measurements be made. Measurements of heat flux and temperature are used to separately determine heat transfer coefficients for the pins and the base region between the pins. Three pitch to diameter ratios (distance from pin center to pin center measured diagonally) were studied: P/d = 3/1, 9/4, 3/2. Heat generation was accomplished using cartridge heaters inserted into a copper block. The high thermal conductivity of the copper ensured that the surface beneath the heat sink would be at a constant temperature. The cooling fluid was air and the experiments were conducted with a Reynolds numbers based on a porous media type hydraulic diameter ranging from 500 to 25000. The channel had a shroud that touches the fin tips, eliminating any flow bypass. The pin surface heat transfer coefficients match the values reported by Kays and London and by Zukauskas. The base region heat transfer coefficients were, surprisngly, larger than the pin values.

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