The Experimental Study of Phase Transformation Heat─Transfer in Simulation of Grinding of Ti Alloy

2007 ◽  
Vol 359-360 ◽  
pp. 548-553
Author(s):  
Jia Long Ren ◽  
Wei Li ◽  
Hua Hang ◽  
Xiao Yan Guan
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Phase Transformation ◽  
Test Sample ◽  
Air Cooling ◽  
Ti Alloy ◽  
Apparent Mass ◽  
Jet Cooling ◽  
Forced Air ◽  
Positive Effect

Enhancing the cooling to spread heat in the process of the material cutting and milling has positive effect on increasing the efficiency of cutting and milling and assuring the apparent mass of test sample cut and milled. Basing on the experiment about the mixture of fixed pressure, fixed air and different quantity of water atomizing jet cooling the Ti alloy, this article discusses performance and regulation of phase transformation heat—transfer of simulating grinding Ti alloy forced air cooling by the mixture of fixed pressure, fixed air and little water.

Optimized Heat Transfer for High Power Electronic Cooling Using Arrays of Microjets

2004 ◽  
Vol 127 (7) ◽  
pp. 760-769 ◽  
Author(s):  
Matteo Fabbri ◽  
Vijay K. Dhir
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Heat ◽  
Copper Surface ◽  
Electronic Cooling ◽  
Geometrical Parameters ◽  
Air Cooling ◽  
Jet Cooling ◽  
High Heat Transfer ◽  
Forced Air

Electronic cooling has become a subject of interest in recent years due to the rapidly decreasing size of microchips while increasing the amount of heat flux that they must dissipate. Conventional forced air cooling techniques cannot satisfy the cooling requirements and new methods have to be sought. Jet cooling has been used in other industrial fields and has demonstrated the capability of sustaining high heat transfer rates. In this work the heat transfer under arrays of microjets is investigated. Ten different arrays have been tested using deionized water and FC40 as test fluids. The jet diameters employed ranged between 69 and 250μm and the jet Reynolds number varied from 73 to 3813. A maximum surface heat flux of 310W∕cm2 was achieved using water jets of 173.6μm diameter and 3mm spacing, impinging at 12.5m∕s on a circular 19.3mm diameter copper surface. The impinging water temperature was 23.1°C and the surface temperature was 73.9°C. The heat transfer results, consistent with those reported in the literature, have been correlated using only three independent dimensionless parameters. With the use of the correlation developed, an optimal configuration of the main geometrical parameters can be established once the cooling requirements of the electronic component are specified.

A Two-Dimensional Conjugate Heat Transfer Model for Forced Air Cooling of an Electronic Device

1989 ◽  
Vol 111 (1) ◽  
pp. 41-45 ◽  
Author(s):  
A. Zebib ◽  
Y. K. Wo
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Electronic Device ◽  
Transfer Problem ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Air Cooling ◽  
Two Dimensional ◽  
Component Design ◽  
Forced Air

Thermal analysis of forced air cooling of an electronic component is modeled as a two-dimensional conjugate heat transfer problem. The velocity field in a constricted channel is first computed. Then, for a typical electronic module, the energy equation is solved with allowance for discontinuities in the thermal conductivity. Variation of the maximum temperature with the average air velocity is presented. The importance of our approach in evaluating possible benefits due to changes in component design and the limitations of the two-dimensional model are discussed.

Jet Cooling at the Rim of a Rotating Disk

1979 ◽  
Vol 101 (1) ◽  
pp. 68-72 ◽  
Author(s):  
D. E. Metzger ◽  
W. J. Mathis ◽  
L. D. Grochowsky
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Impinging Jets ◽  
Turbine Engine ◽  
Transfer Rates ◽  
Jet Cooling ◽  
Geometric Conditions ◽  
Face Contour

Results are presented from an experimental study conducted to measure heat transfer rates at the rim of a rotating disk convectively cooled by impinging jets. The disk face contour radially inward from the rim is varied to simulate the geometric conditions found on gas turbine engine rotors. Heat transfer rates are found to be relatively unaffected by impingement for jet flowrates less than the order of one-tenth the disk pumping flow. Disk pumping flows are evaluated through the use of an analysis which accounts for the presence of the disk hub. At larger jet flowrates, heat transfer rates increase strongly with increasing jet flow, reaching two to three times the no-impingement values at jet flowrates approximately equal to the pumped flow. All the heat transfer results, both with and without jet impingement, are essentially unaffected by changes in the disk face contour.

Experimental Study on Cryogenic Gas Atomization Jet Cooling Difficult-to-Cut Material

2015 ◽  
Vol 1095 ◽  
pp. 736-740
Author(s):  
Xiao Yan Guan ◽  
Ai Sheng Wu
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Phase Change ◽  
Cooling Effect ◽  
Air Cooling ◽  
Gas Atomization ◽  
Cold Air ◽  
Jet Cooling ◽  
Nickel Base ◽  
Phase Change Heat Transfer

Based on pool film boiling, the model of boiling and vaporization to heat transfer is established When droplet jet into cutting zone to cool high temperature wall. Through the transient experiment of cryogenic gas atomization jet cooling high temperature nickel-base alloys and Titanium alloys surface with different water dose. The water dose achieving the best cooling effect is obtained at different temperature on surface of Nickel based alloys and TI-alloy. It is indicated that the water dose to the best cooling effect must be equivalent to the amount of water that materials can vaporize and participate in the phase change heat transfer under certain temperature. When achieving optimal cooling effect, the amount of droplets participating in phase change heat transfer to cool high temperature wall are the most , while comparing the cold air cooling effect and spraying cooling effect at low and high temperature. Result is that either low or high temperature, spraying cooling effect is superior than cold air cooling effect, but at a specific temperature, no lower the temperature of air, the better cooling effect, there is also an optimal air temperature values.

Thermal Performance Maps for Forced Air Cooling of Ruggedized Electronics Enclosures

2007 ◽  
Author(s):  
Jesse VanEngelenhoven ◽  
Gary L. Solbrekken ◽  
Karl J. L. Geisler
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Dissipation ◽  
Side Wall ◽  
Form Factors ◽  
Air Cooling ◽  
Heat Transfer Capacity ◽  
Flow Pressure ◽  
Forced Air ◽  
Analytic Models

Based on standard commercial form factors, this study explores chassis-level air cooling limits for ruggedized military electronics enclosures constrained by pressure drop requirements and fin manufacturing capabilities. Numeric and analytic models are developed and used to define a methodology for optimizing the geometry of longitudinal plate fins included in side wall ducts to maximize the amount of heat that can be dissipated from an air-cooled chassis. The results of these analyses are presented in the form of a performance map facilitate the identification of particular fin manufacturing process well-suited for a specified set of mass flow, pressure drop, and heat transfer requirements. Analysis results demonstrate that if isothermal boundaries can be achieved, the heat transfer capacity of the chassis will increase relative to isoflux boundary condition assumptions. As a means to this end, the incorporation of heat pipes into the chassis wall is explored to enhance heat spreading and approach the isothermal limits of heat dissipation in the airflow ducts.

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