scholarly journals Heat and Mass Transfer in the Vicinity of the Vapor-Gas Front in a Gas-Loaded Heat Pipe

1972 ◽  
Vol 94 (2) ◽  
pp. 155-162 ◽  
Author(s):  
D. K. Edwards ◽  
B. D. Marcus
Keyword(s):  
Mass Transfer ◽  
Heat Pipe ◽  
Heat And Mass Transfer ◽  
Heat Pipes ◽  
Mass Diffusion ◽  
Working Fluid ◽  
Predictive Capability ◽  
Axial Mass ◽  
Axial Heat ◽  
And Control

An analysis is presented of axially conducting gas-controlled heat pipes leading to a predictive capability for the heat and mass transfer along the heat pipe. In addition, experimental results are presented which verify the analysis, and computational results are presented which show the relative influence of various parameters which affect the system behavior. In particular it was found that axial heat conduction is of much greater importance than axial mass diffusion in establishing the wall temperature profiles and condenser heat-transfer characteristics of gas-loaded heat pipes. However, mass diffusion and, consequently, the choice of working fluid and control gas are of considerable importance in establishing the “diffusion freezeout rate” if the potential exists for freezing of vapor which penetrates the gas-blocked portion of the condenser. It is believed that the analysis and associated computer program are useful tools for designing gas-loaded heat pipes.

Entrainment Limitations in Thermosyphons and Heat Pipes

1991 ◽  
Vol 113 (3) ◽  
pp. 147-153 ◽  
Author(s):  
G. P. Peterson ◽  
B. K. Bage
Keyword(s):  
Experimental Data ◽  
Heat Pipe ◽  
Heat Recovery ◽  
Large Range ◽  
Heat Pipes ◽  
Working Fluid ◽  
Physical Parameters ◽  
Modeling Techniques ◽  
Fluid Properties ◽  
Axial Heat

The isothermal characteristics and high effective thermal conductivity of heat pipes and thermosyphons make them particularly useful in air to air and process to air heat recovery systems. Although previous investigations have developed successful techniques for predicting many of the transport limitations, entrainment remains the least understood. Current entrainment modeling techniques have resulted in a large range in the predicted axial heat flux required for the onset of entrainment. Included here is a review of the present analytical methods used to predict the liquid entrainment as a function of the pipe’s physical parameters and working fluid properties, for both thermosyphons and heat pipes. The results of the models are compared with existing experimental data in an effort to determine the accuracy of the predictive techniques. Using a sample copper/water thermosyphon and a similar screen wicked heat pipe, comparisons of the experimental entrainment limit and those predicted by seven thermosyphon and four heat pipe models were made. The results of this comparison can provide insight for designers developing heat pipe exchangers and will provide a basis for further understanding the phenomena which govern this limit.

scholarly journals Mathematical Modeling of Heat and Mass Transfer in Heat Pipes in a One-Dimensional Formulation when Cooling Active Phased Antenna Arrays

2021 ◽  
Vol 15 ◽  
pp. 196-203
Author(s):  
S. Radaev
Keyword(s):  
Mass Transfer ◽  
Heat Pipe ◽  
Heat And Mass Transfer ◽  
Antenna Arrays ◽  
Saturation Temperature ◽  
Heat Pipes ◽  
Equilibrium Temperature ◽  
One Dimensional ◽  
Phased Antenna Arrays ◽  
The Mathematical Model

The work proposes test one-dimensional models of heat and mass transfer in heat pipes during cooling of active phased antenna arrays, which can be used in processing the test results of flat heat pipes in order to determine their performance characteristics and identify the parameters required for modeling in a more complex setting (for example, in flat and taking into account the presence of several localized sources of heat supply). To take into account the influence of the heat release power on the equilibrium temperature inside the heat pipe, the model has been added to take into account the dependence of the steam saturation temperature on the pressure, which is realized inside the steam pipeline when the heat pipe is heated. Numerous calculations carried out made it possible to refine the mathematical model. In particular, a significant effect on the temperature distribution along the heat pipe is shown, taking into account the dependence of the steam saturation temperature on the pressure in the parawire. It is shown that the introduction of standard functions for the characteristics of the coolant (water) in the liquid and vapor state, as well as taking into account the capillary pressure on temperature, makes it possible to refine the resulting solution.

Steady Two-Dimensional Heat and Mass Transfer in the Vapor-Gas Region of a Gas-Loaded Heat Pipe

1973 ◽  
Vol 95 (3) ◽  
pp. 377-382 ◽  
Author(s):  
A. R. Rohani ◽  
C. L. Tien
Keyword(s):  
Mass Transfer ◽  
Heat Pipe ◽  
Heat And Mass Transfer ◽  
Species Conservation ◽  
Heat Pipes ◽  
Mass Conservation ◽  
Gas Diffusion ◽  
Two Dimensional ◽  
Axial Conduction ◽  
Thermodynamic Equilibrium Condition

A numerical analysis is made of the steady two-dimensional heat and mass transfer in the vapor-gas region of a gas-loaded heat pipe. Consideration is given to a cylindrical heat pipe with typical evaporator, condenser, and noncondensible-gas sections and with negligible axial conduction through the wall and the liquid-wick matrix. The elliptical mass, momentum, energy, and species conservation equations have been solved in conjunction with the overall energy and mass conservation constraints and the thermodynamic equilibrium condition for three heat pipe cases with different working fluids and diameters. The results show that in certain gas-loaded heat pipes, such as liquid-metal heat pipes, vapor-gas diffusion and two-dimensionality must be considered in the analysis. Extension of the present numerical framework to more general cases such as including the axial wall conduction is indicated.

Experimental study of heat and mass transfer in a cryogenic heat pipe

1975 ◽  
Vol 28 (1) ◽  
pp. 19-21 ◽  
Author(s):  
L. L. Vasil'ev ◽  
V. G. Kiselev ◽  
M. A. Litvinets ◽  
A. V. Savchenko
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Heat Pipe ◽  
Heat And Mass Transfer

Heat and mass transfer in heat pipes with noncondensing gas

1973 ◽  
Vol 25 (2) ◽  
pp. 988-992
Author(s):  
L. L. Vasil'ev ◽  
S. V. Konev
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Pipes

scholarly journals The effect of operating parameters on the heat transfer in the heat pipe

2021 ◽  
Vol 2119 (1) ◽  
pp. 012088
Author(s):  
A. A. Litvintceva ◽  
N. I. Volkov ◽  
N. I. Vorogushina ◽  
V. A. Moskovskikh ◽  
V. V. Cheverda
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Temperature Difference ◽  
Heat Pipes ◽  
Working Fluid ◽  
Operating Parameters ◽  
Temperature Stabilization ◽  
Ir Camera ◽  
Fluid Properties

Abstract Heat pipes are a good solution for temperature stabilization, for example, of microelectronics, because these kinds of systems are without any moving parts. Experimental research of the effect of operating parameters on the heat transfer in a cylindrical heat pipe has been conducted. The effect of the working fluid properties and the porous layer thickness on the heat flux and temperature difference in the heat pipe has been investigated. The temperature field of the heat pipe has been investigated using the IR-camera and K-type thermocouples. The data obtained by IR-camera and K-type thermocouples have been compared. It is demonstrated the power transferred from the evaporator to the condenser is a linear function of the temperature difference between them.

scholarly journals An investigation on effect of EDL on heat transfer of micro heat pipe with square and triangular cross section

2020 ◽  
Vol 21 (3) ◽  
pp. 309
Author(s):  
Maryam Fallah Abbasi ◽  
Hossein Shokouhmand ◽  
Morteza Khayat
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Double Layer ◽  
Electric Double Layer ◽  
Heat Pipes ◽  
The Body ◽  
Working Fluid ◽  
Two Phase ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

Electronic industries have always been trying to improve the efficiency of electronic devices with small dimensions through thermal management of this equipment, thus increasing the use of small thermal sinks. In this study micro heat pipes with triangular and square cross sections have been manufactured and tested. One of the main objectives is to obtain an understanding of micro heat pipes and their role in energy transmission with electrical double layer (EDL). Micro heat pipes are highly efficient heat transfer devices, which use the continuous evaporation/condensation of a suitable working fluid for two-phase heat transport in a closed system. Since the latent heat of vaporization is very large, heat pipes transport heat at small temperature difference, with high rates. Because of variety of advantage features these devices have found a number of applications both in space and terrestrial technologies. The theory of operation micro heat pipes with EDL is described and the micro heat pipe has been studied. The temperature distribution have achieved through five thermocouples installed on the body. Water and different solution mixture of water and ethanol have used to investigate effect of the electric double layer heat transfer. It was noticed that the electric double layer of ionized fluid has caused reduction of heat transfer.

scholarly journals Numerical simulation of heat and mass transfer in a 3D model of a loop heat pipe evaporator

2017 ◽  
Vol 3 (3) ◽  
pp. 210-217 ◽  
Author(s):  
Aleksey A. Pozhilov ◽  
Dmitri K. Zaitsev ◽  
Evgueni M. Smirnov ◽  
Aleksander A. Smirnovsky
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Heat Pipe ◽  
Heat And Mass Transfer ◽  
3D Model ◽  
Loop Heat Pipe
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