Experimental study of effects of wicks and boundary conditions on thermal performance of heat pipes

Author(s):  
Foster Kwame Kholi ◽  
Hariharan Kallath ◽  
Alberto Mucci ◽  
Man Yeong Ha ◽  
Jason Chetwynd-Chatwin ◽  
...  
2008 ◽  
Vol 12 (3) ◽  
pp. 91-102 ◽  
Author(s):  
Lutful Mahmood ◽  
Razzaq Akhanda

An experimental study of three different cross-sections (circular, semicircular and rectangular) of micro heat pipes having same hydraulic diameter (D= 3mm) is carried out at three different inclination angles (0?, 45?, 90?) using water as the working fluid. Evaporator section of the pipe is heated by an electric heater and the condenser section is cooled by water circulation in an annular space between the condenser section and the water jacket. Temperatures at different locations of the pipe are measured using five calibrated K type thermocouples. Heat supply is varied using a voltage regulator which is measured by a precision ammeter and a voltmeter. It is found that thermal performance tends to deteriorate as the micro heat pipe is flattened. Thus among all cross-sections of the pipes circular cross-section exhibits the best thermal performance followed by semicircular and rectangular cross-sections. Moreover maximum heat transfer capability of the pipes also decreases with decreasing of its inclination angle. A correlation is developed using all the gathered data of the present study to predict the heat transfer coefficient of micro heat pipes of different cross-sections placed at different inclination angles.


2018 ◽  
Vol 136 (1) ◽  
pp. 389-400 ◽  
Author(s):  
G. Kumaresan ◽  
P. Vijayakumar ◽  
M. Ravikumar ◽  
R. Kamatchi ◽  
P. Selvakumar

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.


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