| Summary: | 碩士 === 建國科技大學 === 自動化工程系暨機電光系統研究所 === 96 === ABSTRACT
This thesis experimentally explores a porous packed bypass channel with variable flow orientations for energy storage feature, the experimental parameter includes flow orientation combinations, sizes of packed spheres, and flow rates. Under air forced convection condition, one could figure out the optimum parameters for both noise and thermal-fluid characteristic considerations. For flow orientation parameter, two flow orientation designs (parallel or perpendicular to the exit) are applied to the packed copper spheres matrix channel. For all experimental tests, there are five inlet and outlet arrangements for all experimental tests (A1, A2, A3, B1 and B2), two sphere sizes variations (dp=2 and 6mm), and 12 forced-convection parameters (Reynolds numbers, Re=377, 785, 1194, 1612, 2488, 3343, 3925, 6036, 8249, 12449, 17004, and 22460). The experimental results reveal that B2 flow orientation arrangement has the optimum overall heat transfer performance, and A1 flow orientation arrangement get the worst. Complete overall heat transfer performance rankings of all flow orientations are B2＞B1＞A3＞A2＞A1. The dominating cause of experimental results is the porosity of packed copper beads. For a larger porosity =0.6444 (dp=6mm), flow resistance of the packed channel is lower, the air forced convection is more effective, and the ratio of fluid pass through the bypass channel is much less than the smaller porosity (=0.2296, dp=2mm). One can induce the empirical correlations for relational applications. Furthermore, if one simultaneously considers heat transfer and noise factors for a specified pumping power (f Re3), B2 is still the best choice among all of the cases.
Keywords: packed spheres, noise, forced convection, Reynolds number, porosity
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