Flow Visualization within the Evaporator of Planar Loop Heat Pipe

2005 ◽  
Author(s):  
Junwoo Suh
Keyword(s):  
Flow Visualization ◽  
Heat Pipe ◽  
Loop Heat Pipe

A Flow Visualization Study on the Temperature Oscillations Inside a Loop Heat Pipe With Flat Evaporator

2013 ◽  
Author(s):  
Dongchuan Mo ◽  
Guansheng Zou ◽  
Shushen Lu ◽  
L. Winston Zhang
Keyword(s):  
Flow Visualization ◽  
Heat Pipe ◽  
Temperature Oscillation ◽  
Heating Power ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Interface Motion ◽  
Temperature Oscillations ◽  
Flat Evaporator ◽  
Compensation Chamber

This paper presents a flow visualization study on the temperature oscillations inside a loop heat pipe in order to gain a better understanding of its heat transfer characteristics. A flat loop heat pipe (FLHP) with a flat evaporator instead of a typical cylindrical evaporator was built using copper as the shell and water as the working fluid. An experimental setup was designed by using the transparent material instead of copper in some parts of the FLHP. The experiment results showed that there were at least three different flow patterns in the vapor line as the heating power increased. The temperatures in different locations of the loop oscillated even when the heating power was kept constant. The largest amplitude of the temperature oscillation in the loop was located at the condenser outlet. It was found that the temperature oscillation at the condenser outlet could be divided into two types, one with smaller amplitudes and the other with larger amplitudes. The smaller amplitude temperature oscillations were always there when the heating power was increased step by step, while the larger amplitude temperature oscillations would disappear initially and show up later. Finally, the location of the vapor/liquid interface inside the condenser varied with the temperature oscillations, resulting in liquid/vapor interface motion in the compensation chamber.

Theoretical and Experimental Study of a Loop Heat Pipe at Positive Elevation

2004 ◽  
Author(s):  
Po-Ya Abel Chuang ◽  
John M. Cimbala ◽  
Jack S. Brenizer ◽  
C. Thomas Conroy
Keyword(s):  
Steady State ◽  
Flow Visualization ◽  
Heat Pipe ◽  
Neutron Radiography ◽  
Loop Heat Pipe ◽  
Operating Characteristics ◽  
Two Phase ◽  
State Behavior ◽  
Wide Range ◽  
Two Phase Heat Transfer

A loop heat pipe (LHP), which is a two-phase heat transfer device, was studied experimentally and theoretically. The steady-state operating characteristics of a LHP when it is operated at adverse (the condenser is below the evaporator) and zero elevations (the evaporator and the condenser are at the same level) had been studied intensively in the past. However, study of a LHP when it is operated at positive elevation (the condenser is above the evaporator) is still lacking. This paper presents detailed theoretical analysis of the steady-state behavior of a LHP operated at positive elevation. The present analysis agrees with experimental results, and is confirmed by flow visualization images. Testing was performed for a wide range of heat loads (20 W-600 W) at three positive elevations: 25.4mm, 76.2mm, and 127mm. Flow visualization images were taken by neutron radiography when the LHP was operated at 102mm positive elevation.

EXPERIMENTAL COMPARISON OF LOOP HEAT PIPE PERFORMANCE WITH VARIOUS EVAPORATOR DESIGNS

2014 ◽  
Vol 5 (1-4) ◽  
pp. 287-294
Author(s):  
S. Ouenzerfi ◽  
T. Barreteau ◽  
C. Petit ◽  
Valerie Sartre ◽  
Jocelyn Bonjour ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Experimental Comparison ◽  
Loop Heat Pipe
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