The Constrained Vapor Bubble Fin Heat Pipe in Microgravity

2011 ◽  
Vol 50 (15) ◽  
pp. 8917-8926 ◽  
Author(s):  
Arya Chatterjee ◽  
Peter C. Wayner ◽  
Joel L. Plawsky ◽  
David F. Chao ◽  
Ronald J. Sicker ◽  
...  
Author(s):  
Arya Chatterjee ◽  
Joel L. Plawsky ◽  
Peter C. Wayner ◽  
David F. Chao ◽  
Ronald J. Sicker ◽  
...  

The constrained vapor bubble (CVB) experiment is an experiment in thermal fluid science currently operating on the International Space Station. Flown as the first experiment on the Fluids Integrated Rack on the Destiny module of the US part of the space station, the experiment promises to provide new and exciting insights into the working of a wickless micro heat pipe in the micro-gravity environment. The CVB consists of a relatively simple setup — a quartz cuvette with sharp corners partially filled with pentane as the working fluid. Along with temperature and pressure measurements, the curvature of the pentane menisci formed at the corners of the cuvette can be determined using optical measurements. This is the first time the data collected in space environment is being presented to the public. The data shows that, while the performance of the CVB heat pipe is enhanced due to increased fluid flow, the loss of convection as a heat loss mechanism in the space environment, leads to some interesting consequences. We present some significant differences in the operating characteristics of the heat pipe between the space and Earth’s gravity environments and show that this has important ramifications in designing effective radiators for the space environment.


Author(s):  
Joel L. Plawsky ◽  
Peter C. Wayner

The Constrained Vapor Bubble (CVB) is a prototype for a wickless heat pipe and was developed into an experiment that was run in the microgravity environment of the International Space Station during 2010. Since the CVB is transparent, we can visualize the flow processes within the device in a way not possible before. Results from the experiment indicate that the CVB operates at higher pressures and temperatures in microgravity, a consequence of radiation being the only mechanism for removing heat from the device. The temperature profile data along the heat pipe and corresponding heat transfer calculations indicate that CVB performance is enhanced in the microgravity environment due to increased capillary flow even though heat transfer to the external environment is diminished by the absence of natural convection. Image data of the liquid profile in the grooves of the heat pipe indicate that the curvature gradient is considerably different from that on Earth and supports the conclusion that capillary flow and internal heat transfer is increased. Operations with the 20 mm version of the device allowed us to view explosive nucleation within the CVB upon device start-up. In this scenario, bubble nucleation occurred spontaneously and periodically at the hot end of the device. The nucleation process sent a shock wave through the pipe that collapsed the original bubble as a new vapor space was generated. The newly formed bubble returned to its original size, shape and location as heat loss from the CVB reestablished the original, pseudo-steady-state temperature and pressure profiles.


2013 ◽  
Vol 27 (2) ◽  
pp. 309-319 ◽  
Author(s):  
Arya Chatterjee ◽  
Joel L. Plawsky ◽  
Peter C. Wayner ◽  
David F. Chao ◽  
Ronald J. Sicker ◽  
...  

2001 ◽  
Author(s):  
Ying-Xin Wang ◽  
Peter Wayner, Jr. ◽  
Ling Zheng ◽  
Joel Plawsky

Author(s):  
Radhakanta Sarangi ◽  
Satya Prakash Kar ◽  
Abhilas Swain ◽  
Lalit Kumar Pothal

Abstract Numerical modelling of multi turn Closed Loop Pulsating Heat Pipe (CLPHP) is presented in this paper for ethanol as working fluid. Modelling is carried out for 1mm and 2mm ID PHP for different number of turns, different orientations and at constant wall temperature boundary conditions. Momentum and heat transfer variations with time are investigated numerically solving the one dimensional governing equations for vapor bubble and liquid plugs. Evaporation and condensation takes place by heat transfer through liquid film present around the vapour bubble. The code takes into account the realistic phenomena such as vapour bubble generation, liquid plug merging and super heating of vapor bubbles above its saturation temperature. During merging of liquid plugs, a time step adaptive scheme is implemented and this minimum time step was found to be 10−7 s. Nature of flow is investigated by momentum variation plot. Model results are compared with the experimental results from literature for nine different cases. Maximum variation in heat transfer for all these cases is found to be below ±34%. Keywords: Closed Loop Pulsating Heat Pipe, Liquid Plug, Plug momentum, Vapor Bubble, Heat Transfer, Thin Film Evaporation and Condensation


Author(s):  
J. Huang ◽  
M. Karthikeyan ◽  
Joel L. Plawsky ◽  
Peter C. Wayner, Jr.

1997 ◽  
Vol 1 (2) ◽  
pp. 111-118 ◽  
Author(s):  
P. C. Wayner, Jr.

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