Session 14: Heat Pipes

Chair:

Edson Bazzo
Departamento de Engenharia Mecânica Universidade Federal de Santa Catarina






s14p01

SIMULAÇÃO NUMÉRICA DE UM TUBO DE CALOR AXIALMENTE ROTATIVO COM ESTRUTURA POROSA PARA BOMBEAMENTO CAPILAR DO CONDENSADO

Luís E. Saraiva - [email protected]
Universidade de Passo Fundo, Faculdade de Engenharia e Arquitetura
Campus Bairro São José - 99001-970 - Passo Fundo - RS
Kamal A.R. Ismail - [email protected]
Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica, DETF
Cidade Universitária Zeferino Vaz - 13083-970 - Campinas - SP

A non-tapered (internally cylindrical) axially rotating heat pipe is numerically studied.  The governing equations for vapor and liquid flow through porous medium are simultaneously solved by the SIMPLE method.  Temperature, pressure, axial, radial and tangencial velocities profiles are presented in terms of parameters like heat transfer rate and rotational speed.

Keywords:  Rotating heat pipes, Rotating flow, Phase change heat transfer.
 
 



s14p02

PERFORMANCE ANALYSIS OF CAPILLARY PUMPS INTEGRATED TO FLAT SOLAR COLLECTORS

Edson Bazzo - [email protected]
Fernando Marcelo Pereira
Luciano Heinen
Gabriel I. Medina Tapia - [email protected]
Universidade Federal de Santa Catarina
Departamento de Engenharia Mecânica
88.040-900, Florianópolis - SC

This paper presents the thermal performance of a circumferentially grooved capillary pump integrated into a solar plate collector. Experimental results are obtained for a solar heating system in small scale, consisting of a circumferentially grooved capillary pump mounted on a copper flat plate of 46 cm length and 6 cm width. Tests carried out in the laboratory showed good agreement with theoretical results, found out from analytical and numerical models. Heat loads capacities up to 500 W/m 2 are expected.
 
 



s14p03

CRYOGENIC HEAT PIPES - A REVIEW OF THE STATE OF THE ART

Paulo Couto - [email protected]
Federal University of Santa Catarina - Department of Mechanical Engineering
P.O. Box 476 - Trindade - 88040-900 - Florianopolis - SC - Brazil

Marcia B. H. Mantelli - [email protected]
Federal University of Santa Catarina - Department of Mathematics
P.O. Box 476 - Trindade - 88040-900 - Florianopolis - SC - Brazil

Cryogenic heat pipe is one of the satellite thermal control device, which is used mainly for the thermal control of optical surfaces, infrared scanning systems, or large super-conducting magnets in the space environment. Actually, researches are being conducted in including other applications of cryogenic heat pipes, such as the cooling of electronic de-vices, particularly in microgravity environments. The technology of cryogenic heat pipes is now under investigation on the Satellite Thermal Control Laboratory of the Federal Univer-sity of Santa Catarina. This paper presents a review of the cryogenic heat pipes researches available in the literature. A review of ground testing and microgravity experiments is pre-sented as well as their contributions.

Keywords: Heat Pipe, Cryogenics, and Satellite Thermal Control.
 
 



s14p04

PERFORMANCE OF A TWO-PHASE THERMOSYPHON OPERATING AT OPTIMAL INCLINATION AND VERTICAL POSITION - EXPERIMENTAL STUDY

Marco A. W. Cavalcanti - [email protected]
Universidade Federal da Paraíba, Laboratório de Energia Solar, CT/ CPGEM - DTM
Cx. P. 5115, CEP 58051-970, João Pessoa, PB, Brasil

Valérie Sartre - [email protected]
Monique Lallemand - [email protected]
INSA de Lyon, CETHIL - Equipe Energétique et Thermique, UPRES A CNRS 5008, Villeurbanne, France

An experimental study is developed on the performance of a cylindrical two-phase closed thermosyphon, of the type Cu-R113, filled at 100 % of evaporator volume, operating at optimal inclination and vertical position. The optimal angle was previously determined by an experimental study. Four operating temperatures are investigated (60, 70, 80 e 90 ºC) and the power supplied at the evaporator is between 600 and 2200 W. The condenser and evaporator thermal performances are analyzed by the heat transfer coefficients evaluation on the condenser and evaporator as function of the thermal power. Finally, the thermosyphon global performance is analyzed by the global thermal resistance evaluation. Vertical and optimal inclination results are compared for operating temperature of 80 ºC.

Keywords: Two-phase thermosyphon, Optimal angle, Condensation, Thermal resistance, Experimental study
 
 



s14p09

STEADY STATE SIMULATION OF HEAT PIPES IN CRITICAL CONDITIONS OF HEAT FLUX AND ROTATION

Humberto Araujo Machado - [email protected]
Universidade do Vale do Paraíba, UNIVAP - IP&D
Av Shishima Hifume, 2911, 12244-000, São José dos Campos, SP, Brazil

Ricardo Fortes de Miranda- [email protected]
Universidade Federal de Uberlândia, Faculdade de Engenharia Mecânica
Campus Santa Mônica, bloco 1M, 38400-902, Uberlândia, MG, Brazil.

Rotating circular heat pipes have some important applications, as electric engines cooling, turbine thermal control, etc. The effect of rotation in its work becomes important in both critical cases, when the angular velocity or heat flux are too large, compared to the heat transfer and fluid flow scales. In this work, a steady rotating cylindrical heat pipe is simulated through the finite volume method, coupling the vapor zone and porous media. Several values for angular and linear Reynolds number, as functions of angular velocity and heat flux, respectively, are showed, as well the effects of such variation in the streamlines of the whole heat pipe dominium. A limit for heat pipe operation, taking into account the losses
of heat exchange capacity, is presented as a curve related to the Reynolds numbers, which can be useful for heat pipe design.

Keywords: Rotating heat pipes, Finite volume, Phase change in porous media