Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7055029 | International Journal of Heat and Mass Transfer | 2017 | 12 Pages |
Abstract
Micro-grooved wicks with reentrant cavity array (MGRAs) were fabricated with orthogonal Ploughing/Extrusion method for the application in the ultra-thin aluminum vapor chambers. Capillary rise tests using both ethanol and acetone as the working fluid were conducted by a novel IR-thermal imaging method. The experimental results indicated that the MGRAs yielded larger capillary height than the micro-grooved wicks (MGs) and the MGRA-1 exhibited the highest capillary rise rate of all samples studied. In addition, the permeability was characterized in the force flow tests. It was found that the MGRAs obtained comparable permeability to that for the MGs, revealing that they were able to enhance the capillary rise with little penalty of pressure drop. With regard to the capillary limited heat flux, the capillary parameter K·ÎPcap was employed to evaluate the performance of the wicks comprehensively. The comparison of K·ÎPcap between the prediction with/without the gravitational effect showed that the Washburn's Law greatly underestimated the K·ÎPcap after the initial stage, so the gravitational effect should be taken into account when comparing the samples. In this case, K·ÎPcap determined in the ethanol and acetone tests were similar. Besides, the MGRAs yielded higher K·ÎPcap than that for the MGs, except for the MGRA-3/MG-3 couple, justifying the prominent performance of the MGRAs. Despite the fact that the MGRA-2 failed to obtain the largest capillary height, it showed the largest K·ÎPcap among all MGRAs due to the good balance between the capillary pressure and permeability. Thus, it may be the optimum choice of all MGRAs in this study.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Jian Zeng, Lang Lin, Yong Tang, Yalong Sun, Wei Yuan,