An experimental study on thermal contact resistance and interfacial pressure of bolt-joined aluminum foams

• Main Author: 張廷舜
• Other Authors: Yeh. C. L.
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/57877203388306135488

碩士 === 大葉大學 === 機械工程學系碩士班 === 92 === An experimental investigation of thermal contact resistance of aluminum foams (Al6061) was conducted. The aluminum foam with a diameter of 63.5 mm was sandwiched between two aluminum cylinders and the whole assembly was fasten by bolts. The heat was transferred through the sample by the one-dimensional thermal conduction. Two types of bolt patterns were used in this study: the first type has 3 bolts with the diameter of 5 mm, and the second type has 6 bolts of 5 mm in diameter. Effects of physical properties of Al foams, such as PPI (pores per inch), R.D. (relative density), and sample height on the thermal contact resistance of Al foams were studied. In addition, the influence of bolt pattern was also discussed. The torque applied on each bolt was in the range from 0.1 to 0.5 N-m. The heat flux through the test specimen was about 50~150KW/m2. In this study, the interfacial pressure between Al foams and Al cylinder was measured by the pressure measuring film. Results show that the interface pressure increases with the increase of applied torque. The contact surface area increases with the interfacial pressure. The variation in bolt pattern produced almost no effect on the interfacial contact pressure. Experimental results indicated that the temperature drop across the Al foam decreases and the total thermal conductance increases when the relative density of Al foam increases. The thermal contact resistance decreases with increasing applied torque, due to the increase of interfacial pressure and contact area. However, the increase of number of bolts from 3 to 6 produced nearly no influence on the contact resistance. An increase in the sample height led to the increase of total thermal resistance, but the contact resistance was independent of the sample height. Among all of the properties, the PPI has most pronounced effect on the thermal resistance. Both total and contact resistances increase with an increase in the PPI value of the Al foam.