Both parallel and staggered plate fin arrays have shown promise for use inhigh performance heatsinks regard of its individual manufacturing costs. The geometrical andoperational parameters are very important to their ...Both parallel and staggered plate fin arrays have shown promise for use inhigh performance heatsinks regard of its individual manufacturing costs. The geometrical andoperational parameters are very important to their cooling performance as heatsinks in practicalapplications. Fluent 5.0 commercial CFD (computational fluid dynamic) code is used to simulate theflow and heat transfer of those heatsinks of different realistic parameters. Based on thosesimulations, two correlations, concerning Nusselt number and friction factor as the functions ofgeometrical and operational parameters, FB (fin-base area ratio), PR' (ratio of spanwise pitch tolengthwise pitch) and Re, were developed. From the both, the performance comparisons for optimizinggeometrical and operational parameters of a fixed dimension heatsink are shown at constant pumpingpower and constant thermal resistance. Several optimized parameters were obtained can out performthe staggered ones.展开更多
CFD has penetrated into the field of electronic cooling for some time. Both parallel and staggered plate fin heatsinks are widely used in modern computers. This paper presents the ways to make most use of CFD in optim...CFD has penetrated into the field of electronic cooling for some time. Both parallel and staggered plate fin heatsinks are widely used in modern computers. This paper presents the ways to make most use of CFD in optimization design of those heatsinks: the flow and heat transfer of staggered and parallel plate fm heatsinks of various geometry were simulated by using Fluent 5.0 commercial CFD code. Based on 60 different simulation solutions, two correlations, concerning Nusselt number and friction factor as the functions of geometrical and operational parameters of the heatsinks were developed. The presentation parameter examination was also performed by comparing the numerical solutions with the analytical solutions of parallel plate arrays, showing that the correct parameters are used in the correlations.展开更多
In order to control the ferrite and austenite percentage in duplex stainless steel welding, many researchers try to change the laser welding parameters and cooling medium, but ignore to study the influence of heat sin...In order to control the ferrite and austenite percentage in duplex stainless steel welding, many researchers try to change the laser welding parameters and cooling medium, but ignore to study the influence of heat sink effect on weld strength. In this work, the effect of aluminium heat sink and varying cooling medium on the laser welding of duplex stainless steel (DSS) 2205 is studied. The 2 mm thick DSS sheets welded with pulsed Nd: YAG laser welding machine by varying the cooling medium (air and oil) and an aluminium plate used as a heat sink. The welded specimens tested for tensile strength, micro-hardness, distortion, microstructure and radiography analysis. The faster cooling rate in the oil quenching process enhances the ferrite percentage compared with air-cooled samples. But the faster cooling rate in oil quenching leads to more distortion and using aluminium as a heat sink influenced positively the distortion to a small extent. The lower cooling rate in air quenching leads to a higher tensile strength of the welded specimen. The objective of this work is to analyse experimentally the effect of cooling medium and heat sink in the mechanical and metallurgical properties of laser welded duplex stainless steel.展开更多
文摘Both parallel and staggered plate fin arrays have shown promise for use inhigh performance heatsinks regard of its individual manufacturing costs. The geometrical andoperational parameters are very important to their cooling performance as heatsinks in practicalapplications. Fluent 5.0 commercial CFD (computational fluid dynamic) code is used to simulate theflow and heat transfer of those heatsinks of different realistic parameters. Based on thosesimulations, two correlations, concerning Nusselt number and friction factor as the functions ofgeometrical and operational parameters, FB (fin-base area ratio), PR' (ratio of spanwise pitch tolengthwise pitch) and Re, were developed. From the both, the performance comparisons for optimizinggeometrical and operational parameters of a fixed dimension heatsink are shown at constant pumpingpower and constant thermal resistance. Several optimized parameters were obtained can out performthe staggered ones.
文摘CFD has penetrated into the field of electronic cooling for some time. Both parallel and staggered plate fin heatsinks are widely used in modern computers. This paper presents the ways to make most use of CFD in optimization design of those heatsinks: the flow and heat transfer of staggered and parallel plate fm heatsinks of various geometry were simulated by using Fluent 5.0 commercial CFD code. Based on 60 different simulation solutions, two correlations, concerning Nusselt number and friction factor as the functions of geometrical and operational parameters of the heatsinks were developed. The presentation parameter examination was also performed by comparing the numerical solutions with the analytical solutions of parallel plate arrays, showing that the correct parameters are used in the correlations.
文摘In order to control the ferrite and austenite percentage in duplex stainless steel welding, many researchers try to change the laser welding parameters and cooling medium, but ignore to study the influence of heat sink effect on weld strength. In this work, the effect of aluminium heat sink and varying cooling medium on the laser welding of duplex stainless steel (DSS) 2205 is studied. The 2 mm thick DSS sheets welded with pulsed Nd: YAG laser welding machine by varying the cooling medium (air and oil) and an aluminium plate used as a heat sink. The welded specimens tested for tensile strength, micro-hardness, distortion, microstructure and radiography analysis. The faster cooling rate in the oil quenching process enhances the ferrite percentage compared with air-cooled samples. But the faster cooling rate in oil quenching leads to more distortion and using aluminium as a heat sink influenced positively the distortion to a small extent. The lower cooling rate in air quenching leads to a higher tensile strength of the welded specimen. The objective of this work is to analyse experimentally the effect of cooling medium and heat sink in the mechanical and metallurgical properties of laser welded duplex stainless steel.
