| With the rapid development of science and technology, the devices are being developed towardsthe direction of miniaturization, high-integrated and high-frequency in the fields of, aerospaceelectro-mechanical, energy and bio-industry and so on. The heat flux of the devices is higher andhigher,cooling having become increasingly difficult. The traditional heat transfer equipments can notmeet the cooling requirements.To research the compacted high-performance heat transfer equipmentfor high power devices is the current research focus on electronic equipment cooling, is the importantissue about the study of the basic theory and engineering application for heat transfer.Serrated-fins are commonly used in the single-phase fluid heat exchanger, it increases the heattransfer surface area, disturbance the fluid efficiently, and enhance heat transfer obviously. For theresearch of phase transition flow and heat transfer in serrated-fins channel is fewer. In this paper,R134a as the mobile media, experimentally studied the flow and heat transfer characteristics of phasetransitions in the serrated fin channel, providing data to support the design and verification for phasetransition heat exchanger.In this paper, a phase transition flow and heat transfer test system, with R134as refrigerant,wasdesigned and built, in order to study the flow and heat transfer characteristics of refrigerantevaporation and condensation in a serrated-fin channel. the equivalent diameter is1.594mm.observingits flow patterns and recording them with the camera.The mass flow rate of working fluid is50~200kg/m2s, by this test obtaining the relationship between the friction loss and averageconvective heat transfer coefficient and the mass flow rate, and analyzing the local heat transfercoefficient varying with the bubble ratio of working fluid in the evaporation process.From the resultswe know that: in the refrigerant evaporation and condensation heat transfer, the average convectiveheat transfer coefficient and the flow resistance increases with the increase of mass flow rate. Underthe same conditions, the resistance and heat transfer coefficient of the refrigerant evaporation processwere greater than the refrigerant condensing process. |
