Theoretical Realizability of Dream-Pipe-Like Oscillating/Pulsating Heat Pipe

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Masao Furukawa
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Capillary Tube ◽  
Feasibility Studies ◽  
Temperature Fields ◽  
Pulsating Heat Pipe ◽  
Long Distance ◽  
Effective Thermal Diffusivity ◽  
Energy Equations ◽  
Adiabatic Section

The state of the art of thermally self-excited oscillatory heat pipe technology is briefly mentioned to emphasize that there exists no oscillating/pulsating heat pipe (OHP/PHP) suited to long-distance heat transport. Responding to such conditions, this study actively proposes a newly devised conceptually novel type of OHP/PHP. In that heat pipe, the adiabatic section works as it were the dream pipe invented by Kurzweg. This striking quality of the proposed new-style OHP/PHP produces high possibilities of long-distance heat transport. To support such optimistic views, an originally planned mathematical model is introduced for feasibility studies. Hydraulic considerations have first been done to understand what conditions are required for sustaining bubble-train flows in a capillary tube of interest. Theoretical analysis has then been made to solve the momentum and energy equations governing the flow velocity and temperature fields in the adiabatic section. The obtained analytical solutions are arranged to give algebraic expressions of the effective thermal diffusivity, the performance index combined with the tidal displacement, and the required electric power. Computed results of those three are displayed in the figures to demonstrate the realizability of that novel OHP.

Study on a Pulsating Heat Pipe With Self-Rewetting Fluid

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Koji Fumoto ◽  
Masahiro Kawaji ◽  
Tsuyoshi Kawanami
Keyword(s):  
Surface Tension ◽  
Heat Pipe ◽  
Heat Transport ◽  
Heated Surface ◽  
Input Power ◽  
Water Mixture ◽  
Pulsating Heat Pipe ◽  
Maximum Heat ◽  
Dry Spot ◽  
Heat Transport Capability

This paper discusses a pulsating heat pipe (PHP) using a self-rewetting fluid. Unlike other common liquids, self-rewetting fluids have the property that the surface tension increases with temperature. The increasing surface tension at a higher temperature can cause the liquid to be drawn toward a heated surface if a dry spot appears and thus to improve boiling heat transfer. In experiments, 1-butanol and 1-pentanol were added to water at a concentration of less than 1 wt % to make self-rewetting fluid. A pulsating heat pipe made from an extruded multiport tube was partially filled with the self-rewetting fluid water mixture and tested for its heat transport capability at different input power levels. The experiments showed that the maximum heat transport capability was enhanced by a factor of 4 when the maximum heater temperature was limited to 110°C. Thus, the use of a self-rewetting fluid in a PHP was shown to be highly effective in improving the heat transport capability of pulsating heat pipes.

scholarly journals A Dynamic Film Model of the Pulsating Heat Pipe

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Vadim S. Nikolayev
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Capillary Tube ◽  
Numerical Code ◽  
Oscillating Flow ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Thermally Induced ◽  
Film Evaporation ◽  
Condensation Model

This article deals with the numerical modeling of the pulsating heat pipe (PHP) and is based on the film evaporation/condensation model recently applied to the single-bubble PHP (Das et al., 2010, “Thermally Induced Two-Phase Oscillating Flow Inside a Capillary Tube,” Int. J. Heat Mass Transfer, 53(19–20), pp. 3905–3913). The described numerical code can treat the PHP of an arbitrary number of bubbles and branches. Several phenomena that occur inside the PHP are taken into account: coalescence of liquid plugs, film junction or rupture, etc. The model reproduces some of the experimentally observed regimes of functioning of the PHP such as chaotic or intermittent oscillations of large amplitudes. Some results on the PHP heat transfer are discussed.

scholarly journals Study of a Single, Straight Tube Pulsating Heat Pipe (Oscillation Behavior and Heat Transport Characteristics)

2012 ◽  
Vol 78 (788) ◽  
pp. 881-893 ◽  
Author(s):  
Kunito OKUYAMA ◽  
Satoshi KAMIDOZONO ◽  
Jun IYESHIMA ◽  
Shunske KATO ◽  
Shoji MORI
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Straight Tube ◽  
Pulsating Heat Pipe

scholarly journals Experimental Study on the Starting-Up and Heat Transfer Characteristics of Pulsating Heat Pipe Under Local Low-Frequency Vibrations

2021 ◽  
Author(s):  
Jing Chen ◽  
Junbiao Dong ◽  
Ye Yao
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Low Frequency ◽  
Heating Power ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Condensation Section ◽  
Adiabatic Section

This study mainly experimentally investigates and explores the effects of local low-frequency vibrations on the starting-up and heat transfer characteristics of the pulsating heat pipe. A micro motors with the vibration frequency of 200 Hz were imposed on the external surface of evaporation, condensation and adiabatic section of the pulsating heat pipe, respectively, and the starting-up temperature and the average temperatures along the evaporation section as well as the thermal performances of the vibrating heat pipe were experimentally scrutinized under the local vibrations of different positions. The following important conclusions can be achieved by the experimental study: 1) The effect of vibrations at the evaporation section and at the adiabatic section on the starting-up time of pulsating heat pipe is more significant than that at the condensation section. 2) The vibrations at different positions can reduce the starting-up temperature of the pulsating heat pipe. The effect of the vibrations at the evaporation section is the best as the heating power is lower, and the effect of the vibration at the adiabatic section is the best as the heating power is higher. 3) The vibrations at the evaporation section and at the adiabatic section can reduce the thermal resistance of the pulsating heat pipe. However, the vibrations at the condensation section have little effect on the thermal resistance of the pulsating heat pipe. 4) The vibrations at the evaporation section and at the adiabatic section can effectively reduce the temperature of evaporation section of the pulsating heat pipe, but the vibrations at the condensation section have no effect on the temperature of evaporation section of the pulsating heat pipe.

scholarly journals Performance and impact of cryogenic pulsating heat pipe using a different number of turns and helium gas

2021 ◽  
pp. 210-210
Author(s):  
Arunkumar Munimathan ◽  
Mohanavel Vinayagam ◽  
Prabhu Rajalingam ◽  
Ganesamoorthy Raju ◽  
Suban Kaveripakkam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Pipe ◽  
High Capacity ◽  
Temperature Response ◽  
Heat Transfer Process ◽  
Pulsating Heat Pipe ◽  
Long Distance ◽  
Transfer Capability ◽  
Dry Out

The present work involves the development of helium based Pulsating heat pipe (PHP), which containing 48 parallel tubing parts. Pulsating heat pipe (PHP) is considered as one of the best alternatives for conducting metals and it is used for long distance heat transfer process. Their heat transfer capability and efficient thermal conductivity are the prominent properties which considered for applications. The region of the condenser was thermally sealed to the giffored mcmohanon cryo-cooler [gm-cryo cooler] using a cooling cap of 1.49 W at 4.2 K while 1.1 W of heat are allowed to the evaporator section at a filling rate of 70%, through comparing the 48-turn PHP and 8-turn PHP, a most intense efficient thermal conductivity of 12329 W/ mK was achieved in the 48 turn PHP. The influence of no turns of warm movement execution was observed with the same operating parameters and topographical parameters. Observations revealed that the temperature variations of PHP 48-turn was significantly less than that of PHP 8-turn. It exhibited efficient thermal conductivity, high capacity heat transfer and a good dry-out temperature response. Thus PHP 48-turn of series and parallel configurations are defined as excellent system designs and are accessible to the PHP cryogenics framework architecture.

Heat Transport Characteristics of a Pulsating Heat Pipe

2007 ◽  
Author(s):  
Takao Nagasaki ◽  
Toshiyuki Hokazono ◽  
Yutaka Ito
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Heat Load ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Load Range ◽  
Large Heat ◽  
Inner Diameter ◽  
Bottom Heat ◽  
Better Than

Heat transport characteristics of a closed loop pulsating heat pipe (PHP) have been investigated experimentally. The heat pipe consists of 12 turn copper pipes with 2mm inner diameter. The lengths of heating, adiabatic and cooling sections are 53mm, 100mm and 51mm, respectively. The heat load was varied up to nearly 1000W for water and R141b as the working fluid. Three kinds of orientation, bottom heat vertical, horizontal, and top heat vertical, were tested. Detailed measurements of wall temperature fluctuations for water revealed several characteristic operating behaviors, such as intermittent oscillation and thermosyphon-like behavior. The performance of PHP with R141b is better than that with water in small heat load range due to its independence of orientation, conversely, PHP with water was more efficient than R141b in large heat load range. In order to improve the performance of PHP with R141b, diamond particles were added, resulting in better performance than water in the whole range of heat load.

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