The Performance and Experimental Investigation of Bubble Pump of Electronic Cooling System
Date Issued
2011
Date
2011
Author(s)
Kuo, Sy-Chi
Abstract
This study experimentally investigates the bubble pump performance of electronic cooling system. The vertical-type and horizontal-type bubble pumps are investigated. In the first part, the bubble pump is placed vertically which is a closed-loop system. This closed-loop system consists of a vertical flat chamber as a bubble pump, a condenser, a rising tube, a falling tube and a reservoir, and is completely filled with working fluid. As the bubble pump absorbs heat, the working fluid density differences between two vertical closed-loop tubes induce flow motion. The effects of the input heating power, inlet fluid temperature and boiling surface of the bubble pump are experimentally determined. Three heat transfer regions describe the heat transfer mechanisms inside the pump, such as natural convection, subcooled boiling and saturated boiling. A theoretical pressure drop model of the entire loop is constructed to describe the bubble pump performance. The results indicate that the bubble pump performs better at saturated boiling conditions, the experimental result of the maximum flow rate is 200 ml/min at 30 W, and the maximum driving pressure of the pump is 962 Pa at 80 W. Besides, the results show that a sudden contraction between the pump chamber and the rising tube, inducing a contraction pressure drop inside the pump chamber, will reduce the system flow rate. The results also show that the fins on the boiling surface can effectively diminish the center temperature of the lower plate and pump thermal resistance. The fins on the boiling surface can averagely reduce 19% and 13% with natural convection and subcooled boiling conditions, respectively.
In the second part, the bubble pump is placed horizontally which is an open system. This open system consists of a horizontal flat chamber as a bubble pump and a reservoir. As the bubble pump absorbs heat, the working fluid starts boiling and produces bubbles to push flow motion. The effects of the input heating power and the structure of diffuser on the boiling surface of the bubble pump are experimentally determined. The results indicate that the bubble pump performs better with single diffuser and the maximum flow rate is 18 ml/min at 35 W. Besides, the same structures of boiling surfaces make the similar thermal performance.
Subjects
Bubble pump
Vertical-type
Horizontal-type
Flow pattern
Diffuser
Pressure drop analysis
Type
thesis
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