tailieunhanh - Báo cáo hóa học: "Particle shape effect on heat transfer performance in an oscillating heat pipe"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Particle shape effect on heat transfer performance in an oscillating heat pipe | Ji et al. Nanoscale Research Letters 2011 6 296 http content 6 1 296 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Particle shape effect on heat transfer performance in an oscillating heat pipe Yulong Ji1 2 Corey Wilson1 2 Hsiu-hung Chen 2 and Hongbin Ma2 Abstract The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe OHP was investigated experimentally. A binary mixture of ethylene glycol EG and deionized water 50 50 by volume was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet blade cylinder and brick were studied respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode they can enhance the heat transfer performance of an OHP. Introduction Utilizing the thermal energy added on the oscillating heat pipe OHP the OHP can generate the oscillating motion which can significantly increase the heat transport capability. Compared with the conventional heat pipe the OHP has a number of unique features 1 an OHP has a higher thermal efficiency because it can convert some thermal energy from the heat generating area into the kinetic energy of liquid plugs and vapor bubbles to initiate and sustain the oscillating motion 2 the liquid flow does not interfere with the vapor flow because both phases flow in the same direction resulting in low pressure drops 3 the structure of liquid plugs and vapor bubbles inside the capillary tube can significantly enhance evaporating and condensing heat transfer 4 the