Production Stainless Gravitational Heat Pipes Filled with Distilled Water

2016 ◽  
Vol 832 ◽  
pp. 184-191 ◽  
Author(s):  
Marián Jobb ◽  
Ľuboš Kosa ◽  
Michal Holubčík ◽  
Radovan Nosek
Keyword(s):  
Heat Pipe ◽  
Operating Temperature ◽  
Heat Pipes ◽  
Distilled Water ◽  
Aisi 304 ◽  
Working Temperature ◽  
Essential Function ◽  
Aisi 316 ◽  
Process Measurements ◽  
Pipe Manufacturing

This article deals with the performance of heat pipes, depending on the operating temperature and positions (operation angle). There is described the essential function of the heat pipe manufacturing process. Measurements were carried at an operating temperature of 40 °C to 90 °C. Stainless heat pipes were made of three kinds of materials AISI 304, AISI 310, AISI 316 and filled with a distilled water, up to 20% of the heat pipe inner volume. For each material was selected heat pipe with the best results. The heat pipes were measured at various angles of vertical inclination (0 ° - 90 °), at the working temperature 90 ° C. The performance was measured on the experimental device. Presented results show the progress of individual measurements and the effect of operating parameters on the performance of heat pipes.

Operational Limitations of Heat Pipes With Silver-Water Nanofluids

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Lazarus Godson Asirvatham ◽  
Rajesh Nimmagadda ◽  
Somchai Wongwises
Keyword(s):  
Silver Nanoparticles ◽  
Heat Pipe ◽  
Heat Load ◽  
Operating Temperature ◽  
Particle Diameter ◽  
Heat Pipes ◽  
Working Fluid ◽  
Limit Value ◽  
Capillary Limit ◽  
Nanoparticles Concentration

The paper presents the enhancement in the operational limits (boiling, entrainment, sonic, viscous and capillary limits) of heat pipes using silver nanoparticles dispersed in de-ionized (DI) water. The tested nanoparticles concentration ranged from 0.003 vol. % to 0.009 vol. % with particle diameter of <100 nm. The nanofluid as working fluid enhances the effective thermal conductivity of heat pipe by 40%, 58%, and 70%, respectively, for volume concentrations of 0.003%, 0.006%, and 0.009%. For an input heat load of 60 W, the adiabatic vapor temperatures of nanofluid based heat pipes are reduced by 9 °C, 18 °C, and 20 °C, when compared with DI water. This reduction in the operating temperature enhances the thermophysical properties of working fluid and gives a change in the various operational limits of heat pipes. The use of silver nanoparticles with 0.009 vol. % concentration increases the capillary limit value of heat pipe by 54% when compared with DI water. This in turn improves the performance and operating range of the heat pipe.

Thermal Management of a 15 kV/100 kVA Intelligent Universal Transformer

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Ronald Warzoha ◽  
Amy S. Fleischer
Keyword(s):  
Heat Pipe ◽  
Power Electronics ◽  
Thermal Management ◽  
Operating Temperature ◽  
Heat Pipes ◽  
Sensitivity Study ◽  
Design Sensitivity ◽  
Thermal Dissipation ◽  
System Failure ◽  
Significant Challenge

The thermal management of power electronics presents a significant challenge to thermal engineers due to high power loads coupled with small footprints. Inadequate thermal dissipation of these loads can lead to excessively high equipment temperatures and subsequent system failure. In this study, a unique power electronics-based transformer, called the intelligent universal transformer (IUT), is thermally analyzed using the computational fluid dynamics software ICEPAK. The objective of this work is to examine the use of a finned heat pipe array for the power electronics in the IUT. A design sensitivity study was performed to determine the effect of the number of fins attached to the heat pipe array, the number of heat pipes in the heat pipe array, and the fin material on the steady-state operating temperature of the power electronics. It was determined that a set of 33 copper fins attached to an array of 36 heat pipes on each side of the containment unit is sufficient for continuous operation of the power electronics. This analysis and thermal management solution will be applicable not only to this situation but also to other high density power electronics applications.

scholarly journals Improvement of Heat Pipe Solar Collector Thermal Efficiency Using Al2O3/Water and TiO2/Water Nanofluids

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Sinan Ünvar ◽  
Tayfun Menlik ◽  
Adnan Sözen ◽  
Hafız Muhammad Ali
Keyword(s):  
Heat Pipe ◽  
Heat Exchangers ◽  
Base Fluid ◽  
Operating Temperature ◽  
Pure Water ◽  
Heat Pipes ◽  
Working Fluid ◽  
Solar Collectors ◽  
Instantaneous Power ◽  
Operating Temperature Range

Heat pipe solar collectors (HPSCs) are heat exchangers that carry heat based on the phase change of the heat pipe working fluid. It is aimed to increase the operating temperature range of solar collectors by changing the phase of the working fluid in the heat pipe at low temperature. For this reason, it has become widespread to use nanofluids obtained by mixing nanosized metal oxides with the base fluid in certain proportions in order to increase both the thermal conductivity of the heat pipe working fluids and to increase the specific heat closures. The main purpose of this study, which was conducted to evaluate the performance of HPSCs, is to increase performance, and an experimental study has been conducted in this direction. For this purpose, an HPSC designed and manufactured was used. Al2O3-water and TiO2-water nanofluids containing 2% nanoparticles were used in order to increase performance in the study. HPSC used in the study consists of 8 heat pipes with a length of 100 cm. The experiments were carried out for pure water and nanofluids, and their efficiency and strength were compared. The highest value of instantaneous efficiency was calculated as 48% when pure water was used as the working fluid, 58% for Al2O3-water nanofluid, and 64% for TiO2-water nanofluid. The instantaneous power obtained using pure water was determined as 135.66 W, 167.96 W for Al2O3-water nanofluid, and 184.03 W for TiO2-water nanofluid. The improvement in efficiency was determined as 20.8% for Al2O3-water nanofluid and 33.3% for TiO2-water nanofluid. Improvement in powers was found to be 23.8% for Al2O3-water nanofluid and 35.6% for TiO2-water nanofluid.

Thermal Analysis of Edge Illumination Type LED Backlight with Heat Pipe

2013 ◽  
Vol 401-403 ◽  
pp. 339-344 ◽  
Author(s):  
Wo Huan Guan ◽  
Yong Tang ◽  
Xin Rui Ding ◽  
Bin Liu ◽  
Long Sheng Lu
Keyword(s):  
Thermal Analysis ◽  
Steady State ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Thermal Characterization ◽  
Temperature Uniformity ◽  
Working Temperature ◽  
Led Backlight ◽  
Led Arrays

This paper reports on thermal characterization of edge illumination type LED backlight integrated with heat pipes. Heat pipe is integrated with the panel by phase change flattening and expanding process. Thermal capabilities, including the steady-state working temperature and the temperature uniformity along the panels with heat pipes and without heat pipes are compared and analyzed. Results show that the steady-state working temperature on the panel with heat pipes is 1~6°C lower than that on the panel without heat pipes under power range of 15W to 51W of the LED arrays. And the temperature uniformity along the panel with heat pipes is controlled within 2.0°C.

scholarly journals Pengaruh Penggunaan Cascade Straight Heat Pipe Terhadap Temperatur Kerja CPU

Jurnal METTEK ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 84
Author(s):  
I Wayan Gede Widyantara
Keyword(s):  
Data Processing ◽  
Heat Pipe ◽  
Human Activities ◽  
Cooling System ◽  
Great Influence ◽  
Heat Pipes ◽  
Working Temperature ◽  
Human Need ◽  
Very High

Seiring perkembangan jaman, kebutuhan manusia akan komputer sangatlah tinggi. Berbagai aktivitas manusia sekarang mulai mengarah kepada penggunaan komputer. Kalo kita cari artinya, komputer itu adalah alat yang digunakan untuk melakukan pengolahan data. Kadangkala dalam penggunannya komputer mengalami permasalahan yang diakibatkan penggunaan yang berlebihan yang menyebabkan komputer panas sehingga sering terjadi yang namanya lag. Panas ini harus segera dibuang agar tidak merusak komponen hardware lainnya. Sistem pendinginan untuk CPU mulai mengarah pada penggunaan pipa kalor sebagai pendingin. Pipa kalor ini dapat mengatasi panas yang ditimbulkan oleh CPU yang nantinya akan membantu mengembalikan performa dari CPU tersebut. Pendinginan dengan menggunakan pipa kalor dilakukan secara cascade atau bertingkat. Cascade straight heat pipe pada pengujian kali ini terdiri dari single kondensor dan double kondensor yang sama-sama diberikan pembebanan 10 watt, 20 watt, 30 watt, 40 watt dan 48 watt. Pembebanan ini mewakili kondisi CPU saat diberikan beban kerja. Hasilnya cascade straight heat pipe double kondensor sangat memberikan pengaruh yang besar terhadap penurunan temperatur kerja CPU. Terbukti pada pembebanan 48 watt, double kondensor cascade straight heat pipe mampu menurunkan suhu hingga 64,06°C Undeniably, the human need for computers is very high. Various human activities are now beginning  lead to the use of computers. If we look for the meaning, the computer is a tool used for data processing. Sometimes in the use of computers get problems caused by excessive use that causes the computer to heat up so that it often happens that the name lag. This heat must be removed immediately so as not to damage other hardware components.   Today's era, the cooling system for the CPU starts to lead to the use of heat pipes as coolants. This heat pipe can overcome the heat generated by the CPU which will help restore the performance of the CPU. Cooling by using heat pipes is done in a cascade or multilevel manner. The Cascade straight heat pipe in this test consisted of a single condenser and a double condenser which were both given 10 watts, 20 watts, 30 watts, 40 watts and 48 watts of load. This load represents the CPU condition when given a workload. The result is a double condenser cascade straight heat pipe which has a great influence on reducing CPU working temperature. Evidenced by the 48 watt load, the double condenser cascade straight heat pipe can reduce the temperature to 64.06°C

scholarly journals Thermal performance of Pulsating Heat Pipe on Electric Motor as Cooling Application

2018 ◽  
Vol 67 ◽  
pp. 03035 ◽  
Author(s):  
Nurhalimah Aprianingsih ◽  
Adi Winarta ◽  
Bambang Ariantara ◽  
Nandy Putra
Keyword(s):  
Heat Pipe ◽  
Thermal Management ◽  
Thermal Performance ◽  
Electric Motor ◽  
Management System ◽  
Operating Temperature ◽  
Heat Pipes ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Thermal Management System

Heat generated in an electric motor can increase the operating temperature. The excessive operating temperature will reduce the electric motor performance and shorten the service life. An appropriate thermal management system is required to reduce the electric motor operating temperature. The objective of this study is to determine the thermal performance of pulsating heat pipes which applied to the electric motor thermal management system. A prototype of electric motor thermal management system was made from an induction motor with a cartridge heater instead of a heat-generating rotor and stator. Six pieces of pulsating heat pipe were mounted using hexagonal heat pipe holder which placed inside the electric motor housing. The pulsating heat pipes are made of a copper capillary tube using acetone as working fluid with a filling ratio of 0.5. The electric power input was varied from 30 W to 150 W. The use of pulsating heat pipes can reduce the electric motor surface temperature by 55.3°C with the minimum thermal resistance of 0.151°C/W.

Étude de la susceptibilité à la corrosion d’aciers inoxydables AISI 304 ET AISI 316 soumis à des contraintes mécaniques dans l’acide nitrique dilué bouillant en présence de chlorures

1991 ◽  
Vol 79 (1-2) ◽  
pp. 37-49
Author(s):  
D. Desjardins ◽  
M. Puiggali ◽  
A. El Kheloui ◽  
M.C. Petit ◽  
C. Clément ◽  
...  
Keyword(s):  
Aisi 304 ◽  
Aisi 316

scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

The Heat Transport Capacity of Micro Heat Pipes

1998 ◽  
Vol 120 (4) ◽  
pp. 1064-1071 ◽  
Author(s):  
J. M. Ha ◽  
G. P. Peterson
Keyword(s):  
Experimental Data ◽  
Heat Pipe ◽  
Heat Transport ◽  
Heat Pipes ◽  
Original Model ◽  
Semiempirical Model ◽  
Transport Capacity ◽  
Predictive Tool ◽  
Maximum Heat ◽  
Micro Heat Pipes

The original analytical model for predicting the maximum heat transport capacity in micro heat pipes, as developed by Cotter, has been re-evaluated in light of the currently available experimental data. As is the case for most models, the original model assumed a fixed evaporator region and while it yields trends that are consistent with the experimental results, it significantly overpredicts the maximum heat transport capacity. In an effort to provide a more accurate predictive tool, a semi-empirical correlation has been developed. This modified model incorporates the effects of the temporal intrusion of the evaporating region into the adiabatic section of the heat pipe, which occurs as the heat pipe approaches dryout conditions. In so doing, the current model provides a more realistic picture of the actual physical situation. In addition to incorporating these effects, Cotter’s original expression for the liquid flow shape factor has been modified. These modifications are then incorporated into the original model and the results compared with the available experimental data. The results of this comparison indicate that the new semiempirical model significantly improves the correlation between the experimental and predicted results and more accurately represents the actual physical behavior of these devices.

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