INVESTIGATION ON THE STEADY THERMAL RESISTANCE OF AXIAL GROOVED HEAT PIPE(AGHP).pdfVIP

1 Proceedings of the micro/nanoscale heat transfer International Conference MNHT08 January 6-9, 2008, Tainan, Taiwan, China MNHT2008-52021 INVESTIGATION ON THE STEADY THERMAL RESISTANCE OF AXIAL GROOVED HEAT PIPE (AGHP) Hanzhong Tao Hong Zhang Jun Zhuang College of Energy, Nanjing University of technology, Nanjing 210009, P. R. China Tel: +8625-8358-7308 Fax:+8625-8663-7973 Email: hzhang@njut.edu.cn ABSTRACT According to the classic thermal resistance network model of the heat pipe, a quasi-two-dimensional theoretical thermal resistance model for the horizontal axial grooved heat pipe (AGHP) under normal conditions is presented. The contact type between liquid working fluid and groove wall at various axial positions are consi- dered. The two-dimensional mass balance equation and momentum equation are adopted to predict the contact type between liquid working fluid and groove wall, contact point position and the radius of curvature of liquid pool. For the condensate thickness and liquid pool depth, three cases are discussed. The liquid pool depth and circumference radius of curvature of each element along the axial direction can be obtained based on the force balance. The elemental thermal resistance is obtained by superposing the compound layer thermal resistance of liquid working fluid and wick, and conductivity thermal resistance of container wall. Paralleling connection the element thermal resistance at the evaporator and the condenser of the AGHP respec- tively, the thermal resistance of evaporator and condenser are obtained respectively. The overall thermal resistance of the AGHP can be gotten by adding the two parts thermal resistance. The filling amount of working fluid is the sum of vapor and liquid inner the AGHP. The amount of liquid working fluid is the sum of each element in all the grooves. The results from the model are matched the testing results and the tradi- tional semi-empirical correlation. KEYWORDS a