Begell House Inc.
Heat Pipe Science and Technology, An International Journal
HPST
2151-7975
8
1
2017
PREFACE: SELECTED PAPERS FROM THE JOINT 18TH INTERNATIONAL HEAT PIPE CONFERENCE AND THE 12TH INTERNATIONAL HEAT PIPE SYMPOSIUM
v-vi
10.1615/HeatPipeScieTech.v8.i1.10
Seok-Hwan
Moon
Superintelligence Creative Research Laboratory,
Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon, 305-700, Korea
Marcia Barbosa Henriques
Mantelli
Heat Pipe Laboratory (LABTUCAL), Federal University of Santa Catarina, Mechanical Engineering Department, 88040-900, Trindade, Florianopolis, SC, Brazil
FLUID FLOW AND HEAT TRANSFER CHARACTERISTICS OF A JEST-TYPE LOOP THERMOSYPHON
1-12
10.1615/HeatPipeScieTech.2017018793
Ayaka
Suzuki
Department of Advanced Mechanical Systems, Kumamoto University,
2-39-1 Kurokami, Chuo-ku, Kumamoto, Japan
Kaoru
Sato
Department of Advanced Mechanical Systems, Kumamoto University,
2-39-1 Kurokami, Chuo-ku, Kumamoto, Japan
Yasushi
Koito
Department of Advanced Mechanical Systems, Kumamoto University,
2-39-1 Kurokami, Chuo-ku, Kumamoto, Japan
Toshio
Tomimura
Department of Advanced Mechanical Systems, Kumamoto University,
2-39-1 Kurokami, Chuo-ku, Kumamoto, Japan
heat source size
heat transfer coefficient
JEST
loop thermosyphon
two-phase flow
quality
void fraction
A JEST-type loop thermosyphon has new mechanisms: a check valve is located between the liquid line and the evaporator, and a jet induction tube is located in the evaporator. These mechanisms aim at inducting the jet stream in the evaporator for exceeding the cooling performance of conventional
thermosyphons. Fundamental experiments were conducted on the operational characteristics and the cooling performance of a loop thermosyphon. In this study, the experiments
were carried out by changing the heat source size as 1.77 cm2, 4.15 cm2, and 7.07 cm2. From the results, it is confirmed that, irrespective of the heat source sizes, the loop thermosyphon promptly responds to the change in the heat transfer rate. As expected, the heated surface temperature is affected by the heat source sizes; however, the other temperatures and the circulating mass flow rate of the working fluid are hardly affected by the heat source size. In addition, it is also revealed that the heat transfer coefficient at the evaporator is greatly higher than that of conventional thermosyphons. Moreover, the quality and the void fraction of the working fluid
were evaluated, and the fluid flow characteristics in the vapor line were also discussed.
EFFECT OF CONDENSER TEMPERATURE ON THE START-UP OF A PULSATING HEAT PIPE
13-25
10.1615/HeatPipeScieTech.2017018910
L. A.
Betancur
Mechanical Engineer Department, Federal University of Santa Catarina
(UFSC), Brazil
Daniele
Mangini
University of Bergamo, Italy; Advanced Engineering Centre, School of Computing Engineering and Mathematics, Cockcroft Building, Lewes Road, University of Brighton, Brighton BN2 4GJ, UK; ESA/ESTEC Keplerlaan 1, Postbus 299, NL-2200AG Noordwijk, The Netherlands
Mauro
Mameli
University of Pisa, DESTEC, University of Pisa, Largo Lucio Lazzarino 2, 56122 Pisa, Italy
Sauro
Filippeschi
University of Pisa, DESTEC, University of Pisa, Largo Lucio Lazzarino 2, 56122 Pisa, Italy
L. K.
Slongo
Mechanical Engineer Department, Federal University of Santa Catarina
(UFSC), Brazil
K. V.
Paiva
Mechanical Engineer Department, Federal University of Santa Catarina
(UFSC), Brazil
Marcia Barbosa Henriques
Mantelli
Heat Pipe Laboratory (LABTUCAL), Federal University of Santa Catarina, Mechanical Engineering Department, 88040-900, Trindade, Florianopolis, SC, Brazil
Marco
Marengo
Advanced Engineering Centre, School of Computing Engineering and Mathematics, Cockcroft Building, Lewes Road, University of Brighton, Brighton BN2 4GJ, UK; Department of Engineering, University of Bergamo, Viale Marconi 5, 24044 Dalmine (BG), Italy; Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 3, 27100, Pavia, Italy
condenser temperature
pulsating heat pipe
Rohsenow correlation
start-up
A pulsating heat pipe, filled with distilled water, has been designed and tested at different condenser wall temperatures and heat power inputs in vertical position. The device consists of a copper tube (internal and external diameters 3.18 and 4.76 mm), bended into a planar serpentine
with five U-turns in the heated zone. The tube is closed in a loop, evacuated and partially filled with pure water, with a filling ratio of 50%. The heating section is equipped with two heating elements capable of dissipating up to 350 W. A cold plate, directly connected to a thermal bath,
keeps the condenser at a constant temperature in the range from 10°C to 60°C, permitting tests to be performed at different condenser temperature levels. The experimental results show different temperature superheats at different heat fluxes when the condenser temperature and the input
power are modified. Based on experimental data, a theoretical analysis of the heat transfer mechanisms
for the dynamic behavior of the PHP is carried out. The minimum superheating temperature needed to induce boiling has been compared with experimental results. The result of this simplified model, which is based on the Rohsenow equation, is compared with experimental data,
showing good agreement after the full activation of the tested device.
DESIGN, MANUFACTURING, AND CHARACTERIZATION OF COPPER CAPILLARY STRUCTURES FOR LOOP HEAT PIPES
27-49
10.1615/HeatPipeScieTech.2017018805
Rémi
Giraudon
University of Lyon, CNRS, INSA-Lyon, CETHIL UMR5008, F-69621, Villeurbanne, France
Stephane
Lips
University Lyon, CNRS, INSA-Lyon, CETHIL UMR5008, F-69621, Villeurbanne, France
D.
Fabregue
University of Lyon, CNRS, INSA-Lyon, MATEIS UMR5510, F-69621,
Villeurbanne, France
L.
Gremillard
University of Lyon, CNRS, INSA-Lyon, MATEIS UMR5510, F-69621,
Villeurbanne, France
E.
Maire
University of Lyon, CNRS, INSA-Lyon, MATEIS UMR5510, F-69621,
Villeurbanne, France
Valerie
Sartre
University of Lyon, CNRS, INSA-Lyon, CETHIL UMR5008, F-69621,
Villeurbanne, France
loop heat pipe
capillary structure
porosity
permeability
pore radius
manufacturing
sintering
Mono- and bilayer capillary structures are designed by means of a thermohydraulic model of a loop heat pipe in order to optimize the performance of the system. The model tends to show that bilayer wicks with a thermally conducting bottom layer and an insulating top layer are the most
efficient in loop heat pipes. An experimental study is then led to manufacture and characterize the bottom layer. Eight samples made of copper powder are manufactured following a two-level fractional factorial design. The top layer is not manufactured in this study. The sintering parameters
are adjusted to provide porous samples with sufficient mechanical resistance. The porous structure
permeability and its capacity to provide a sufficient capillary pressure are evaluated using a specific
test bench designed for this study, as well as with microstructural observations (tomography, microscopy). The experimental characterization of the samples enables to determine the influence of each sintering parameter as well as the interactions between them. The characteristics of the porous samples are found to be mainly affected by the sintering time and the pressure. High values
of these parameters decrease the permeability and the porosity but increase the maximum capillary
pressure due to a smaller effective pore radius. A set of optimum sintering parameters is found in order to manufacture the bottom layer. The best porous structure is supposed to enhance the latent heat transfer in an LHP.
INNOVATIVE THERMAL DESIGN SATELLITE WITH NETWORKED VARIABLE-CONDUCTANCE OSCILLATING HEAT PIPES
51-67
10.1615/HeatPipeScieTech.2017018788
Naoko
Iwata
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa, Kanagawa, 252-5210, Japan
Hiroyuki
Ogawa
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa, Kanagawa, 252-5210, Japan
Yoshiro
Miyazaki
Thermal Control Laboratory Inc., 6-13-608 Bunkyo, Fukui 910-0017, Japan
Hiroki
Kawai
Asahi Kinzoku Kogyo CO, LTD., 4851-4, Maki, Anpachi-cho, Anpachi-gun,
Gifu, 503-0125, Japan
Seisuke
Fukuda
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa, Kanagawa, 252-5210, Japan
oscillating heat pipe
variable conductance
thermal design
microgravity test
One useful type of an oscillating heat pipe (OHP) is a variable-conductance OHP called VC-OHP in contradiction with the conventional fixed conductance OHP. The operating temperature of an OHP connected to a temperature-controlled liquid reservoir can be controlled by the temperature
of the liquid reservoir such that the operation temperature is almost identical to the liquid reservoir temperature. In this study, a thermal-design-free structure using a VC-OHP network is proposed for use in next-generation small satellites. No thermal design iteration is necessary and
instruments can be mounted without consideration of the thermal design: as a result of the temperature
controllability of the VC-OHPs, the temperatures of the structural panels mounted with all instruments are kept constant even if the locations of the instruments or their heat dissipation characteristics change. A model structure with a 0.027-m3 volume mounting three VC-OHPs was made and tested to demonstrate the thermal-design-free concept. Eighteen heaters are mounted on the two panels to simulate the instruments' heat generation and their heat dissipation to other four panels. Thermal performance tests are conducted under ambient air and thermal vacuum
conditions. The model structure was then mounted on an aircraft and thermal performance under microgravity conditions was examined. The temperatures of the two panels mounting the heaters are maintained at a constant value and are controlled by the reservoir temperature when the amount or the distribution of the heat dissipation is changed. The temperatures of the two panels were maintained when the heat load was put into the radiator. These experiments demonstrate the thermal-design-free concept.
THERMAL MANAGEMENT USING COPPER-METHANOL HEAT PIPES FOR RADIO TRANSMITTER SYSTEMS
69-85
10.1615/HeatPipeScieTech.2017021361
Roger R.
Riehl
National Institute for Space Research INPE/DMC, São José dos Campos,
SP Brazil, 12227-010
thermal management
heat pipes
thermal control
electronics cooling
As well known passive thermal control devices, heat pipes, have been used to transport generated heat from a source to a sink with little temperature differences and high efficiency. Constant development in the field has been achieved over the years and applied in several areas, especially in aerospace and military, with potential applications for cooling industry and laptop computers.
There are several other applications of heat pipes. They can have many different shapes, however, a great deal of development is necessary for a given thermal design especially when high heat density is generated by a source. In applications where a high density of electronics is present, high levels of heat are generated that need to be properly managed in order to maintain their operation
temperatures according to the project's requirements. For the current investigation, heat pipes have been developed as important components for thermal management of electronics on printed circuit boards (PCBs) applied in defense/surveillance equipment. The obtained results
from the development process indicate that heat pipes can present a lifetime of 13.5 years, keeping the cold junction temperatures of the electronic components below 80°C. Thermal tests performed in an environmental chamber showed reliable operation of heat pipes with thermal conductances close to 10 W/°C.
EXPERIMENTAL STUDY OF THE PERFORMANCE OF WATER–COPPER SCREEN MESH WICK HEAT PIPES OPERATING IN POWER CYCLES
87-106
10.1615/HeatPipeScieTech.2018024987
Débora
de O. Silva
Space Mechanics and Control Division − DMC, National Institute for Space
Research, São José dos Campos, 12227-010 SP Brazil
Roger R.
Riehl
National Institute for Space Research INPE/DMC, São José dos Campos,
SP Brazil, 12227-010
thermal conductance
thermal performance
experimental heat pipes
two-phase flow
Nowadays the heat transport technology has been improved by using heat pipes. When compared to conventional methods, the main advantage of involvement of a heat pipe is the transport of large quantities of heat through small cross-sectional areas over a considerable distance only
using heat as the external energy source. The heat pipes are a good choice for different applications such as industrial or aerospace. In the present study, experimental and calculated results for the thermal conductances are presented for three copper heat pipes designed, fabricated, and tested with screen mesh wick as a porous structure operating at a mid-level temperature with power step and power cycles, using water as the working fluid. The objective of this study was to verify the thermal performance of heat pipes, especially when operating in cycles where dryout can occur in the evaporator, interrupting the operation of heat pipes. The thermal conductances obtained from experimental tests were used to correlate the thermal conductance obtained analytically, where it considers an adjustment given by the adjustment actor that involves uncontrolled variables that are inherent to the manufacturing process of heat pipes.