HEAT TRANSFER STUDIES IN A CLOSED LOOP PULSATING HEAT PIPE

2014 ◽  
Vol 5 (1-4) ◽  
pp. 449-456
Author(s):  
Bhawna Verma ◽  
V. L. Yadav ◽  
K. K. Srivastava
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Closed Loop ◽  
Pulsating Heat Pipe

Heat transfer characteristics of a novel closed-loop pulsating heat pipe with a check valve

2018 ◽  
Vol 141 ◽  
pp. 558-564 ◽  
Author(s):  
Chen Feng ◽  
Zhenping Wan ◽  
Haijun Mo ◽  
Heng Tang ◽  
Longsheng Lu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Closed Loop ◽  
Check Valve ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

scholarly journals Experiment Study on Improved Closed Loop Pulsating Heat Pipe with Silver/Water Nanofluid

2013 ◽  
Vol 732-733 ◽  
pp. 462-466
Author(s):  
Wei Xiu Shi ◽  
Wei Yi Li ◽  
Li Sheng Pan
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Pulsating Heat Pipe ◽  
Start Up ◽  
High Heating ◽  
Operation Stability ◽  
Heat Transfer Limit

Start up and heat transfer performances of improved closed loop pulsating heat pipe (ICLPHP) charged with water and silver/water nanofluid, respectively, were investigated experimentally with angles of 90° and 60°. Both the average evaporator wall temperature and the overall thermal resistance of the ICLPHP with different working fluids and at the volume filling ratio of 35% were tested and compared. Experimental results showed that nanofluid caused different thermal performances of ICLPHP. Within the experiment range, silver/water nanofluid can improve operation stability and heat transfer limit and reduce starting power compared with water. With high heating power, thermal resistance of nanofluid was lower than that of water. With inclination of 60°, ICLPHP with nanofluid operated better and reduced sensitivity of inclination.

scholarly journals Study of Thermal Performance of Closed Loop Pulsating Heat Pipe using Computational Fluid Dynamics

2021 ◽  
Vol 9 (9) ◽  
pp. 1384-1388
Author(s):  
K. C. Giri
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Different Temperatures

Abstract: Pulsating heat pipe is a heat transfer device which works on two principles that is phase transition and thermal conductivity which transfer heat effectively at different temperatures. Different factors affect the thermal performance of pulsating heat pipe. So, various researchers tried to enhance thermal conductivity by changing parameters such as working fluids, filling ratio, etc. Analysis of heat transfer characteristics of closed loop pulsating heat pipe (CLPHP) is to be carried out by using Computational Fluid Dynamics. The CLPHP is to be modelled on ANSYS Workbench, the flow of CLPHP is to be observed under specific boundary conditions by using ANSYS Fluent software. Acetone and Water are taken as the working fluid with 70% filling ratio at ambient temperature 30° C and the heat flux of 200 W is supplied at evaporator. Also, the analysis has been done to know the behaviour of PHPs under varying supply of heat flux at evaporator (inlet), the output heat flux is obtained at condenser (outlet) and find out how the heat flux is varying at different temperatures. CFD results shows the heat transfer characteristics observing the performance of CLPHP is a numerical manner. The obtained CFD results are compared with the experimental. The outputs of the simulations are plotted in graphs and outlines. Keywords: Closed Loop Pulsating Heat Pipe, CFD, Heat Transfer, ANSYS.

Modeling for Fluid Flow and Heat Transfer in Closed Loop Pulsating Heat Pipe

2020 ◽  
pp. 1-34
Author(s):  
Radhakanta Sarangi ◽  
Satya Prakash Kar ◽  
Abhilas Swain ◽  
Lalit Kumar Pothal
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Vapor Bubble ◽  
Closed Loop ◽  
Working Fluid ◽  
Vapour Bubble ◽  
Pulsating Heat Pipe ◽  
Time Step ◽  
Liquid Plug ◽  
Evaporation And Condensation

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

Experimental Investigations on the Thermal Performance of a Single Closed Loop Pulsating Heat Pipe Using TiO2 Nanofluid

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
G. V. Pradeep ◽  
K. Rama Narasimha
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Closed Loop ◽  
Experimental Investigations ◽  
Pulsating Heat Pipe ◽  
Vertical Orientation ◽  
Stable Suspension ◽  
Bottom Heating ◽  
Heating Mode

This paper describes the experimental investigations conducted on a closed loop pulsating heat pipe (CLPHP) for assessing the thermal performance. The pulsating heat pipe has a single closed loop made of copper. The working fluids used are water and titanium dioxide nanofluids with varying concentrations of TiO2 nanoparticles (1.5% and 1%) on weight basis. The TiO2 particles are mixed in water to form a stable suspension using a sonicator. The heat input is varied between 40 W and 100 W in steps of 20 W. All experiments are conducted in the bottom heating mode (evaporator at the top) in the vertical and horizontal orientations. The parameters considered for evaluating the thermal performance are the temperature difference between evaporator and condenser, thermal resistance, heat transfer coefficient, and thermal conductivity. The results of the investigation reveal that the vertical orientation and increase in nanoparticle concentration favors better heat transfer performance of the single closed loop pulsating heat pipe.

Experimental Investigation and Performance Evaluation of a Multi Turn Closed Loop Pulsating Heat Pipe

2014 ◽  
Vol 592-594 ◽  
pp. 1554-1558 ◽  
Author(s):  
N. Narendra Babu ◽  
Rudra Naik
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Heat Pipe ◽  
Closed Loop ◽  
Experimental Result ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Working Fluids

Pulsating heat pipe (PHP) is a passive heat transfer device, which transfers heat from one region to another with exceptional heat transfer capacity. It utilizes the latent heat of vaporization of the working fluid as well as the sensible heat. As a result, the effective thermal conductivity is higher than that of the conductors. An experimental study on three turn closed loop pulsating heat pipe with three different working fluids viz., Acetone, Methanol, Heptane and distilled water were employed. The PHP is made up of brass material with an inner diameter of 1.95mm, with a total length of 1150 mm for different fill ratios (FR) was employed .The PHP is tested for the thermal resistance and the heat transfer coefficient. The experimental result strongly demonstrates that acetone is a better working fluid among the working fluids considered in terms of higher heat transfer coefficient and lower thermal resistance.

scholarly journals Effect of Filling Ratio on Heat Transfer Characteristics and Performance of a Closed Loop Pulsating Heat Pipe

2013 ◽  
Vol 56 ◽  
pp. 88-95 ◽  
Author(s):  
Himel Barua ◽  
Mohammad Ali ◽  
Md. Nuruzzaman ◽  
M. Quamrul Islam ◽  
Chowdhury M. Feroz
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
And Performance

Experimental Investigations on Thermal Performance of a Multi-Turn Closed Loop Pulsating Heat Pipe

2012 ◽  
Vol 433-440 ◽  
pp. 5854-5860 ◽  
Author(s):  
Yu Wang ◽  
Wei Yi Li
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Input ◽  
Closed Loop ◽  
Research Work ◽  
Design Parameters ◽  
Working Fluid ◽  
High Heat Flux ◽  
Pulsating Heat Pipe

Closed loop pulsating heat pipe (CLPHP) is a relatively new two-phase passive heat transfer device to suit present requirement of high heat flux dissipation in modern electronic components. The operating mechanism of CLPHP is not well understood and the present state of the technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand thermal performance of CLPHP. A series of experimental investigation were conducted on a multi-turn CLPHP made of copper capillary tube of 2-mm inner diameter. Two kinds of working fluids viz. ethanol and acetone were employed. The influence characterization has been studied for the variation of heat input and filling ratio (FR) of the tested CLPHP. Thermal performance of the CLPHP is evaluated by heat transfer and thermal resistance. The results strongly demonstrate the effect of heat input and FR of the working fluid on thermal performance of the device.

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