Experimental Research on Heat Transfer Characteristics of Pulsating Heat Pipe

Fill Ratio ◽

Transfer Characteristics

Experimental research was conducted to understand heat transfer characteristics of pulsating heat pipe in this paper. The PHP is made of high quality glass capillary tube. The heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage under different fill ratio. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appeares in top heating condition. The flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved for down heating case under different fill ratios and heat transfer rate. The experimental results show that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

Experimental Study on Flow Visualizing and Heat Transfer Characteristic of Pulsating Heat Pipe

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 3 ◽

10.1115/ht2007-32668 ◽

2007 ◽

Author(s):

Li Jia ◽

Dayan Yin

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Heat Transfer Rate ◽

Transfer Rate ◽

Flow Patterns ◽

Bulk Flow ◽

Experimental Results ◽

Pulsating Heat Pipe ◽

Transition Flow ◽

Fill Ratio

The flow of looped pulsating heat pipe was studied by a visualizing experiment, and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The experimental results indicate that bulk flow, transition flow and annular flow are the major flow patterns in PHP. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved. In the experiment, nuclear boiling, the convergence and break up of liquid-plug and vapor-slug were observed. The influence characterization has been done for the variation of fill ration, heat transfer rate, non-condensable gas and inclination angle. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%; the heat resistance is decreased with heat transfer rate, and non-condensable gas also has significant influence on it. The temperature of tubes in heating, condensing and observe sections were recorded, The fluctuation of heat pipe wall temperature was analysed, and the phenomena of suddently increase or decrease of temperature, the unregular fluctuation of temperature were analyzed. Otherwise the response time under different conditions was also analyzed.

Experimental Investigation on the Heat Transfer Characteristics of Nanofluids in Self-Exciting Mode Oscillating-Flow Heat Pipe

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.250 ◽

2011 ◽

Vol 396-398 ◽

pp. 250-254 ◽

Cited By ~ 1

Author(s):

Fu Min Shang ◽

Jian Hong Liu ◽

Deng Ying Liu

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Heat Transfer Rate ◽

Transfer Rate ◽

Working Fluid ◽

Oscillating Flow ◽

Filling Rate ◽

Flow Heat

The objective of this article is to provide the heat transfer characteristics of Cu-H2O nanofluids in self-exciting mode oscillating-flow heat pipe under different laser heating input, and to compare with the heat transfer characteristics of the same heat pipe with distilled water as working fluids. In this paper, the peculiarity of heat transfer rate of the SEMOS heat pipe with Cu-H2O fluid has been experimentally confirmed by changing the proportion of working fluid and Cu nanoscale particles in the heat pipe. As the results, it has been confirmed that the parameter of filling rate of working fluid determine the heat transfer rate of SEMOS heat pipe, although under certain condition heat transfer performance could be improved because of the addition of nanofluids.

Experimental Investigation of the Heat Transfer Characteristics and Operation Limits of a Fork-Type Heat Pipe for Passive Cooling of a Spent Fuel Pool

Energies ◽

10.3390/en14237862 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7862

Author(s):

Changhwan Lim ◽

Jonghwi Choi ◽

Hyungdae Kim

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Heat Transfer Rate ◽

Transfer Rate ◽

Scale Model ◽

Air Cooling ◽

Spent Fuel ◽

Spent Fuel Pool

A fork-type heat pipe (FHP) is a passive heat-transport and air-cooling device used to remove the decay heat of spent nuclear fuels stored in a liquid pool during a station blackout. FHPs have a unique geometrical design to resolve the significant mismatch between the convective heat transfer coefficients of the evaporator and condenser parts. The evaporator at the bottom is a single heat-exchanger tube, whereas the condenser at the top consists of multiple finned tubes to maximize the heat transfer area. In this study, the heat transfer characteristics and operating limits of an FHP device were investigated experimentally. A laboratory-scale model of an FHP was manufactured, and a series of tests were conducted while the temperature was varied to simulate a spent fuel pool. As an index of the average heat transfer performance, the loop conductance was computed from the measurement data. The results show that the loop conductance of the FHP increased with the heat transfer rate but deteriorated significantly at the operating limit. The maximum attainable heat transfer rate of the unit FHP model was accurately predicted by the existing correlations of the counter-current flow limit for a single-rod-type heat pipe. In addition, the instant heat transfer behaviors of the FHP model under different temperature conditions were examined to interpret the measured loop conductance variation and operating limit.

Effect of Inclination Angles on Heat Transfer Characteristics of a Closed Loop Pulsating Heat Pipe (CLPHP)

Procedia Engineering ◽

10.1016/j.proeng.2013.03.092 ◽

2013 ◽

Vol 56 ◽

pp. 82-87 ◽

Cited By ~ 8

Author(s):

Suchana Akter Jahan ◽

Mohammad Ali ◽

Md.Quamrul Islam

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Closed Loop ◽

Pulsating Heat Pipe ◽

Inclination Angles

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.465-466.500 ◽

2013 ◽

Vol 465-466 ◽

pp. 500-504 ◽

Cited By ~ 1

Author(s):

Shahrin Hisham Amirnordin ◽

Hissein Didane Djamal ◽

Mohd Norani Mansor ◽

Amir Khalid ◽

Md Seri Suzairin ◽

...

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Heat Transfer Rate ◽

Heat Exchangers ◽

Transfer Rate ◽

Three Dimensional ◽

Considerable Effect ◽

Louvered Fin

This paper presents the effect of the changes in fin geometry on pressure drop and heat transfer characteristics of louvered fin heat exchanger numerically. Three dimensional simulation using ANSYS Fluent have been conducted for six different configurations at Reynolds number ranging from 200 to 1000 based on louver pitch. The performance of this system has been evaluated by calculating pressure drop and heat transfer coefficient. The result shows that, the fin pitch and the louver pitch have a very considerable effect on pressure drop as well as heat transfer rate. It is observed that increasing the fin pitch will relatively result in an increase in heat transfer rate but at the same time, the pressure drop will decrease. On the other hand, low pressure drop and low heat transfer rate will be obtained when the louver pitch is increased. Final result shows a good agreement between experimental and numerical results of the louvered fin which is about 12%. This indicates the capability of louvered fin in enhancing the performance of heat exchangers.

Numerical Research on Heat Transfer Characteristics Analysis of Two Particles in Supercritical Water

ASME 2021 Heat Transfer Summer Conference ◽

10.1115/ht2021-61486 ◽

2021 ◽

Author(s):

Xiaoyu Li ◽

Zhenqun Wu ◽

Huibo Wang ◽

Hui Jin

Keyword(s):

Heat Transfer ◽

Heat Transfer Rate ◽

Transfer Rate ◽

Local Heat Transfer ◽

Local Heat ◽

Phase Flow ◽

Particle Cluster ◽

Two Phase ◽

Transfer Characteristics

Abstract In the supercritical water (SCW)-particle two-phase flow of fluidized bed, the particles that make up the particle cluster interact with each other through fluid, and it will affect the flow and heat transfer. However, due to the complex properties of SCW, the research on particle cluster is lacking, especially in terms of heat transfer. This research takes two particles as an example to study the heat transfer characteristics between SCW and another particle when one particle exists. This research uses the distance and angle between the two particles as the influencing factors to study the average heat transfer rate and local heat transfer rate. In this research, it is found that the effect is obvious when L/D = 1.1. When L = 1.1D, the temperature field and the flow field will partially overlap. The overlap of the temperature field will weaken the heat transfer between SCW and the particle. The overlap of the flow field has an enhanced effect on the heat transfer between SCW and the particle. The heat transfer between SCW and particles is simultaneously affected by these two effects, especially local heat transfer rate. In addition, this research also found that as the SCW temperature decreases, the thermal conductivity and specific heat of SCW increases, which enhances the heat transfer between SCW and the particles. This research is of great significance for studying the heat transfer characteristics of SCW-particle two-phase flow in fluidized bed.