Advanced heat transfer analysis of a U-shaped pulsating heat pipe considering evaporative liquid film trailing from its liquid slug

2018 ◽  
Vol 138 ◽  
pp. 475-489 ◽  
Author(s):  
Reza Nemati ◽  
Mohammad Behshad Shafii
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Heat Pipe ◽  
Heat Transfer Analysis ◽  
Pulsating Heat Pipe ◽  
Liquid Slug

An Investigation of Evaporation, Boiling, and Heat Transport Performance in Pulstating Heat Pipe

2002 ◽  
Author(s):  
Qingjun Cai ◽  
Reh-Lin Chen ◽  
Chung-Lung Chen
Keyword(s):  
Temperature Gradient ◽  
Liquid Film ◽  
Heat Pipe ◽  
Heat Transport ◽  
Thin Liquid Film ◽  
Pulsating Heat Pipe ◽  
Liquid Slug ◽  
Fill Ratio ◽  
Liquid Heat ◽  
Observation Results

Pulsating heat pipe (PHP) is a latest development in heat pipe technology. In this paper, evaporation and boiling phenomena are investigated, and liquid heat transport performance in a PHP is measured at different fill ratio as well. The observation results show that phase change in the evaporator may occur by two different mechanisms: 1) evaporation and boiling in thin liquid film on the evaporator wall, 2) generation and collapse of tiny bubbles suspended in the liquid slug. Meanwhile, the temperature measurement indicates that temperature gradient between the evaporator and the condenser is related to liquid latent heat, density, viscosity, and mass filled in.

Thermal Performance of an Al2O3–Water Nanofluid Pulsating Heat Pipe

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Sejung Kim ◽  
Yuwen Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Volume Fraction ◽  
Numerical Study ◽  
Pure Water ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Liquid Slug ◽  
Temperature And Pressure ◽  
Vapor Temperature

A numerical study is performed to investigate the effects of nanofluids on the heat transfer performance of a pulsating heat pipe (PHP). Pure water is employed as the base fluid while Al2O3 with two different particle sizes, 38.4 and 47 nm, is used as nanoparticle. Different parameters including displacement of liquid slug, vapor temperature and pressure, liquid slug temperature distribution, as well as sensible and latent heat transfer in evaporator and condenser are calculated numerically and compared with the ones for pure water as working fluid. The results show that nanofluid has significant effect on heat transfer enhancement of the system and with increasing volume fraction and decreasing particles diameter the enhancement intensifies.

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

Effect of ultrasonic on the enhancement of heat transfer for pulsating heat pipe

2021 ◽  
Author(s):  
Dongwei Zhang ◽  
Erhui Jiang ◽  
Zhuantao He ◽  
Chao Shen ◽  
Junjie Zhou
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Pulsating Heat Pipe ◽  
Enhancement Of Heat Transfer

scholarly journals Sodium-Potassium Alloy Heat Pipe under Geyser Boiling Experimental Study: Heat Transfer Analysis

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7582
Author(s):  
Hongzhe Zhang ◽  
Fang Ye ◽  
Hang Guo ◽  
Xiaoke Yan
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heating Power ◽  
Heat Transfer Analysis ◽  
Working Fluid ◽  
Condenser Section ◽  
Sodium Potassium ◽  
Alloy Heat ◽  
Convection Cooling ◽  
Boiling Mode

In the geyser boiling mode, the working fluid state is divided into a boiling process and a quiet process, and the sodium-potassium (Na-K) alloy heat pipe can discontinuously transfer heat at each boiling. The overheating of the liquid working fluid at the bottom causes short-term boiling and forms slug bubble, the strong condensing ability quickly conducts heat from the evaporator section. And geyser boiling can occur before the working fluid forms continuous flow, so it transfers more heat at lower temperatures than natural convection cooling. In this study, the heat transfer process of a Na-K alloy heat pipe with forced convection cooling under different heating power was experimental studied. The geyser boiling mode can make the Na-K alloy heat pipe work below 650 °C and reduce the start-up time. In the process of geyser boiling, the heat transfer quantity was increased by the boiling frequency and the amount of vapor produced in a single boiling. The boiling temperature had no obvious change with the increased of heating power, and the condenser section temperature increased with the heating power.

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