Thermal Analysis of a Micro Heat Pipe

1994 ◽  
Vol 116 (1) ◽  
pp. 189-198 ◽  
Author(s):  
D. Khrustalev ◽  
A. Faghri
Keyword(s):  
Heat Pipe ◽  
Thermal Characteristics ◽  
Shear Stresses ◽  
Maximum Heat ◽  
Micro Heat Pipe ◽  
Wetting Contact Angle ◽  
Maximum Heat Transfer ◽  
Mass Transfer Processes ◽  
Heat Transfer Capacity ◽  
Liquid Vapor

A detailed mathematical model is developed in which the heat and mass transfer processes in a micro heat pipe (MHP) are examined. The model describes the distribution of the liquid in a MHP and its thermal characteristics depending upon the liquid charge and the applied heat load. The liquid flow in the triangular-shaped corners of a MHP with polygonal cross section is considered by accounting for the variation of the curvature of the free liquid surface and the interfacial shear stresses due to a liquid-vapor frictional interaction. The predicted results obtained are compared to existing experimental data. The importance of the liquid fill, minimum wetting contact angle, and the shear stresses at the liquid-vapor interface in predicting the maximum heat transfer capacity and thermal resistance of the MHP is demonstrated.

Thermal Characteristics of Conventional and Flat Miniature Axially Grooved Heat Pipes

1995 ◽  
Vol 117 (4) ◽  
pp. 1048-1054 ◽  
Author(s):  
D. Khrustalev ◽  
A. Faghri
Keyword(s):  
Thermal Characteristics ◽  
Heat Pipes ◽  
Heat Fluxes ◽  
Vertical Position ◽  
Maximum Heat ◽  
Evaporation And Condensation ◽  
Maximum Heat Transfer ◽  
Mass Transfer Processes ◽  
Grooved Surface ◽  
Heat Transfer Capacity

A detailed mathematical model of low-temperature axially grooved heat pipes (AGHP) is developed in which the fluid circulation is considered along with the heat and mass transfer processes during evaporation and condensation. The results obtained are compared to existing experimental data. Both capillary and boiling limitations are found to be important for the flat miniature copper-water heat pipe, which is capable of withstanding heat fluxes on the order of 40 W/cm2 applied to the evaporator wall in the vertical position. The influence of the geometry of the grooved surface on the maximum heat transfer capacity of the miniature AGHP is demonstrated.

Thermal Behavior Analysis of Wire Mini Heat Pipe

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Kleber Vieira de Paiva ◽  
Marcia Barbosa Henriques Mantelli ◽  
Leonardo Kessler Slongo
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Design Parameters ◽  
Working Fluid ◽  
Diffusion Welding ◽  
Flat Plates ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Heat Transfer Capacity ◽  
Microgravity Conditions

This work presents a theoretical and experimental analysis of a copper mini heat pipe (MHP), fabricated from a sandwich formed between cylindrical wires and flat plates, which are welded by means of diffusion process. The edges formed between the wires and the plates provide the working fluid capillary pressure necessary to overcome all the pressure losses. Two different experimental set ups were developed: one for test in gravity (laboratory) and other for microgravity conditions (International Space Station—ISS). The main difference between them lies in the condenser section. In the laboratory, cooling water was used to remove heat from the mini heat pipe, while at the ISS, fins and air fan were employed. In gravity, three different working fluids were tested: water, acetone, and methanol, while, for the experiments at the ISS, just water was used. A model was developed to predict the maximum heat transfer capacity of the device. In comparison to the literature models, the main difference of the present model is the variation of contact angle to adjust the mathematical model. Therefore, the main contributions of the present work are development of wire plate mini heat pipe fabrication methodology using diffusion welding, improvement of the analytical model used to predict the maximum heat transfer capacity of the device, determination of the present technology optimum design parameters, and test data obtained under microgravity conditions.

Design and Research of Flat Micro Heat Pipe with Glass Fiber Wick

2011 ◽  
Vol 483 ◽  
pp. 603-606
Author(s):  
Tian Han ◽  
Xiao Wei Liu ◽  
Chao Wang
Keyword(s):  
Glass Fiber ◽  
Heat Pipe ◽  
Experimental Testing ◽  
Governing Equations ◽  
Maximum Heat ◽  
One Dimensional ◽  
Micro Heat Pipe ◽  
Wick Structure

A kind of flat micro heat pipe with glass fiber wick structure is designed and fabricated. The structure of the wick is presented and also the excellence of the structure is described. For the glass fiber wick, the maximum heat transports is calculated by one-dimensional steady governing equations. Experimental testing is performed for the fabricated micro heat pipe in vacuum. The testing results is presented and analyzed.

Optimization of Wettability Gradient for Enhancement of Thermal Performance of Micro Heat Pipes

2018 ◽  
Author(s):  
Manjinder Singh ◽  
Naresh Varma Datla ◽  
Supreet Singh Bahga ◽  
Sasidhar Kondaraju
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Variable Mass ◽  
Working Fluid ◽  
Maximum Heat ◽  
Continuous Increase ◽  
Maximum Heat Transfer ◽  
Integration Density ◽  
Heat Transfer Capacity ◽  
Micro Heat Pipes

Continuous increase in the integration density of microelectronic units necessitates the use of MHPs with enhanced thermal performance. Recently, the use of wettability gradients have been shown to enhance the heat transfer capacity of MHPs. In this paper, we present an optimization of axial wettability gradient to maximize the heat transfer capacity of the MHP. We use an experimentally validated mathematical model and interior point method to optimize the wettability gradient. For our analysis, we consider two cases wherein (i) the mass of working fluid is constrained, (ii) mass of working fluid is a design variable. Compared to MHP with uniform high wettability and filled with a fixed mass of working fluid, optimization of the wettability gradient leads to 65% enhancement in heat transfer capacity. Similar comparisons for MHP filled with variable mass of working fluid shows more than 90% increase in the maximum heat transfer capacity due to optimization of wettability gradient.

scholarly journals Влияние наножидкостей на теплопередающую способность миниатюрных термосифонов для охлаждения электроники

2019 ◽  
Vol 45 (6) ◽  
pp. 54
Author(s):  
Б.И. Бондаренко ◽  
В.Н. Морару ◽  
В.Ю. Кравец ◽  
Г. Бехмард
Keyword(s):  
Thermal Resistance ◽  
Closed Loop ◽  
Electronics Cooling ◽  
Sharp Decrease ◽  
Vapor Film ◽  
Two Phase ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Boiling Process ◽  
Heat Transfer Capacity

AbstractStable nanofluids based on DG-100 grade carbon black and carbon nanotubes have been prepared, and their influence on the maximum heat-transfer capacity and thermal resistance of closed-loop two-phase thermosyphons (TPTs) intended for electronics cooling have been studied. A more than twofold increase in the critical heat flux of these TPTs as compared to those filled with water has been obtained along with a sharp decrease in their thermal resistance. It is suggested that this effect is not only due to the high thermal conductivity of the proposed nanofluids, but is also related to the formation of a specific porous structure hindering the appearance of a vapor film and enhancing the boiling process.

Sign in / Sign up

Export Citation Format

Share Document