How to improve the thermal performance of pulsating heat pipes: A review on working fluid

2018 ◽  
Vol 91 ◽  
pp. 630-638 ◽  
Author(s):  
Mohammad Alhuyi Nazari ◽  
Mohammad H. Ahmadi ◽  
Roghayeh Ghasempour ◽  
Mohammad Behshad Shafii
Keyword(s):  
Thermal Performance ◽  
Heat Pipes ◽  
Working Fluid

Effects of Surface Coating of Nanoparticles on Thermal Performance of Open Loop Pulsating Heat Pipes

2012 ◽  
Author(s):  
Mehdi Taslimifar ◽  
Maziar Mohammadi ◽  
Ali Adibnia ◽  
Hossein Afshin ◽  
Mohammad Hassan Saidi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Surface Coating ◽  
Heat Pipes ◽  
Open Loop ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Performance Of Heat Transfer

Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated. Experimental results show that ferrofluid has better heat transport capability relative to SC ferrofluid. Furthermore, application of magnetic field improves the heat transfer performance of OLPHPs charged with both ferrofluids.

A Comprehensive Experimental Investigation of the Performance of Closed-Loop Pulsating Heat Pipes

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
M. Halimi ◽  
A. Abbas Nejad ◽  
M. Norouzi
Keyword(s):  
Thermal Resistance ◽  
Flow Regime ◽  
Thermal Performance ◽  
Closed Loop ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Working Fluid ◽  
Physical Parameters ◽  
Two Phase ◽  
Laboratory Conditions

Closed-loop pulsating heat pipes (CLPHPs) are a new type of two-phase heat transfer devices that can transfer considerable heat in a small space via two-phase vapor and liquid pulsating flow and work with various types of two-phase instabilities so the operating mechanism of CLPHP is not well understood. In this work, two CLPHPs, made of Pyrex, were manufactured to observe and investigate the flow regime that occurs during the operation of CLPHP and thermal performance of the device under different laboratory conditions. In general, various working fluids were used in filling ratios of 40%, 50%, and 60% in horizontal and vertical modes to investigate the effect of thermo-physical parameters, filling ratio, nanoparticles, gravity, CLPHP structure, and input heat flux on the thermal performance of CLPHP. The results indicate that three types of flow regime may be observed given laboratory conditions. Each flow regime exerts a different effect on the thermal performance of the device. There is an optimal filling ratio for each working fluid. The increased number of turns in CLPHP generally improves the thermal performance of the system reducing the effect of the type of the working fluid on the aforementioned performance. The adoption of copper nanoparticles, which positively affect fluid motion, decreases the thermal resistance of the system as much as 6.06–42.76% depending on laboratory conditions. Moreover, gravity brings about positive changes in the flow regime decreasing thermal resistance as much as 32.13–52.58%.

Circulation Effectiveness of Working Fluid in Inclined Micro Heat Pipes

2015 ◽  
Vol 789-790 ◽  
pp. 422-425
Author(s):  
Fun Liang Chang ◽  
Yew Mun Hung
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Operating Conditions ◽  
Circulation Rate ◽  
Working Fluid ◽  
High Heat Flux ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

Micro heat pipe is a two-phase heat transfer device offering effective high heat-flux removal in electronics cooling. Essentially, micro heat pipe relies on the phase change processes, namely evaporation and condensation, and the circulation of working fluid to function as heat transfer equipment. The vast applications of micro heat pipe in portable appliances necessitate its functionality under different orientations with respect to gravity. Therefore, its thermal performance is strongly related to its orientation. By incorporating solid wall conduction, together with the continuity, momentum, and energy equations of the working fluid, a mathematical model is developed to investigate the heat and fluid flow characteristics of inclined micro heat pipes. We investigate both the favorable and adverse effects of gravity on the circulation rate which is intimately related to the thermal performance of micro heat pipes. The effects of gravity, through the angle of inclination, on the circulation strength and heat transport capacity are analysed. This study serves as a useful analytical tool in the micro heat pipe design and performance analysis, associated with different inclinations and operating conditions.

Experimental Model to Optimize the Design of Cylindrical Heat Pipes for Solar Collector Application

2013 ◽  
Vol 393 ◽  
pp. 735-740
Author(s):  
Fairosidi Idrus ◽  
Nazri Mohamad ◽  
Ramlan Zailani ◽  
Wisnoe Wirachman ◽  
Mohd Zulkifly Abdullah
Keyword(s):  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Design Parameters ◽  
Working Fluid ◽  
Pipe Material ◽  
Efficient Design ◽  
Wick Structure ◽  
To Come ◽  
Transfer Device

A heat pipe is a heat-transfer device that use the principles of thermal conductivity and phase change to transfer heat between two ends at almost constant temperature. The thermal peformance of cylindrical heat pipes depends on design parameters such as dimensions of the heat pipe, material, wick structure and the working fluid. An experimental strategy was designed to study the effect of these parameters on the thermal performance of cylindrical heat pipes. The experimental design was conceived by employing the Taguchi method. The final aim of the experiments is to come up with design parameters that will yield optimum thermal performance. This paper presents an efficient design of experiment and the associated experimental setup and procedures to be carried out in order to optimize the design of cylindrical heat pipes.

THERMAL PERFORMANCE OF FLAT PLATE PULSATING HEAT PIPES WITH MINI- AND MICROCHANNELS

2014 ◽  
Vol 22 (04) ◽  
pp. 1450025 ◽  
Author(s):  
DONG SOO JANG ◽  
EUN-JI LEE ◽  
SANG HUN LEE ◽  
YONGCHAN KIM
Keyword(s):  
Cross Section ◽  
Working Conditions ◽  
Thermal Performance ◽  
Strong Influence ◽  
Heat Pipes ◽  
Input Power ◽  
Filling Ratio ◽  
Hydraulic Diameter ◽  
Working Fluid ◽  
Optimum Working

This study presents the thermal performance of pulsating heat pipes (PHPs) using distilled water with mini- and microchannels. The PHPs were fabricated with the channels of square cross section which had hydraulic diameters ranged from 1.6 to 3.2 mm in minichannels and from 0.714 to 0.941 mm in microchannels. The performance of the PHPs was measured and analyzed by varying hydraulic diameter, number of turns, filling ratio, and input power. The filling ratio of the working fluid varied from 0% to 100%. The input power was controlled in the range between 3.6 and 150 W. The hydraulic diameter, number of turns, filling ratio, and input power showed strong influence on the performance of the PHP. In the PHP models with mini- and microchannels, optimum working conditions, such as filling ratio and heat input, were quite different according to channel size.

The Performance of Methanol and Water Heat Pipes for Electronics Cooling Applications in Spacecraft Instrumentation

2005 ◽  
Author(s):  
John D. Bernardin
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Thermal Performance ◽  
Electronics Cooling ◽  
Heat Pipes ◽  
Electronic Cooling ◽  
Working Fluid ◽  
Cooling Systems ◽  
Experimental Apparatus ◽  
Moving Parts

Increases in the power density of electronics and the corresponding decreases in packaging space have driven the development and enhancement of numerous electronics cooling strategies. The design of cooling systems for electronics are particularly challenging in spacecraft environments where there exists the additional requirements of minimal mass and volume, high reliability, reduced complexity and number of moving parts, and ability to operate in a reduced or gravity-free environment. One cooling technique that has proven to satisfy these demanding and integrated requirements for spacecraft electronics cooling applications, involves the use of heat pipes. The heat pipe is a passive heat transport device that requires no moving parts, is highly compact and reliable, and is an efficient mover of thermal energy in reduced gravity environments. Despite all of these positive features, heat pipes do have limitations and functional characteristics that designers must be keenly aware of when incorporating them into the development of electronic cooling systems. These include, in part, limits on the heat transport capacity and operational temperature, as well as performance variations between seemingly identical heat pipes due to contamination or manufacturing flaws. This paper discusses thermal analyses and performance testing of commercial copper heat pipes that utilize a sintered copper wick with either methanol or water as the working fluid. First, the electronic cooling application, thermal operating requirements, and commercial heat pipe designs are introduced. Next, the models and analyses used to predict the heat transport limits for the heat pipes are discussed. Following this, the experimental apparatus and procedures used to characterize the thermal performance of the heat pipes are presented. Finally, with the aid of empirical data, assessments of the thermal performance of each heat pipe, the range of performance variation between heat pipes, as well as the applicability and accuracy of the analytical performance models are provided.

Promising Technology for Electronic Cooling: Nanofluidic Micro Pulsating Heat Pipes

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Kambiz Jahani ◽  
Maziar Mohammadi ◽  
Mohammad Behshad Shafii ◽  
Zahra Shiee
Keyword(s):  
Magnetic Field ◽  
Thermal Resistance ◽  
Thermal Management ◽  
Thermal Performance ◽  
Microelectromechanical Systems ◽  
Heat Pipes ◽  
Electronic Cooling ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Thermal Management Of Electronics

Currently, the thermal management of microelectromechanical systems (MEMS) has become a challenge. In the present research, a micro pulsating heat pipe (MPHP) with a hydraulic diameter of 508 μm, is experimented. The thermal performance of the MPHP in both the transient and steady conditions, the effects of the working fluid (water, silver nanofluid, and ferrofluid), heating power (4, 8, 12, 16, 20, 24, and 28 W), charging ratio (20, 40, 60, and 80%), inclination angle (0 deg, 25 deg, 45 deg, 75 deg, and 90 deg relative to horizontal axis), and the application of magnetic field, are investigated and thoroughly discussed. The experimental results show that the optimum charging ratio for water is 40%, while this optimum for nanofluids is 60%. In most of situations, the nanofluid charged MPHPs have a lower thermal resistance relative to the water charged ones. For ferrofluid charged MPHP, the application of a magnetic field substantially reduces the thermal resistance. This study proposes an outstanding technique for the thermal management of electronics.

scholarly journals Potential of Solar Collectors for Clean Thermal Energy Production in Smart Cities using Nanofluids: Experimental Assessment and Efficiency Improvement

2019 ◽  
Vol 9 (9) ◽  
pp. 1877 ◽  
Author(s):  
M. Sarafraz ◽  
Iskander Tlili ◽  
Mohammad Abdul Baseer ◽  
Mohammad Safaei
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Tilt Angle ◽  
Thermal Efficiency ◽  
Smart Cities ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Working Fluid ◽  
Solar Thermal Collector ◽  
Evacuated Tube

In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the collector, mass fraction of the nanoparticles, the solar irradiance, the tilt angle and the filling ratio values of the heat pipes on the thermal performance of the solar collector was investigated. It was found that with an increase in the flow rate of the working fluid within the system, the thermal efficiency of the system was improved. Additionally, the highest thermal performance and the highest temperature difference between the inlet and the outlet ports of the collector were achieved for the nanofluid at wt. % = 0.1. The best tilt angle and the filling ratio values of the collector were 30° and 60% and the maximum thermal efficiency of the collector was 91% for a nanofluid at wt. % = 0.1 and flow rate of 3 L/min.

Sign in / Sign up

Export Citation Format

Share Document