Heat Pipes and Vertical Tectonics in Terrestrial Planets

2020 ◽  
Author(s):  
William Moore ◽  
Alexander Webb
Keyword(s):  
Heat Pipe ◽  
Terrestrial Planet ◽  
High Heat ◽  
Temporal Variations ◽  
Vertical Transport ◽  
Stress Concentrations ◽  
Global Volcanism ◽  
New Material ◽  
Burial Rates ◽  
Horizontal Variations

<p>Terrestrial planet mantles cannot transport the very high heat production in their early stages through subsolidus convection and instead produce voluminous melt that makes its way to the surface to transport the heat. This heat-pipe mode of heat transport implies a very different tectonics than either the rigid or mobile-lid tectonics driven by subsolidus convection. Although  similar to rigid-lid convection in that there is relatively little horizontal motion, heat-pipe lithospheres are by no means stagnant. Vertical transport through the continuous eruption of new material on the surface reaches rates of several mm/year (with significant spatial and temporal variations). This strongly impacts the shape of the geotherm, producing a cold and strong lid (despite the high heat flow). In addition, this vertical transport produces global compressional stresses as old surfaces are buried and forced downward to smaller radii. The horizontal variations in burial rates will lead to stress concentrations and ultimately plastic failure and thrusting (see Io’s numerous tectonic uplifts as an example). The transition from the advectively dominated heat-pipe lithosphere to a thin conductive lithosphere reverses this process, resulting in a period of global extension (again with large horizontal variations) as global volcanism wanes. An additional aspect of vertical transport in the heat-pipe lithosphere is the cycling of water and other volatiles into the lithosphere and mantle as surface materials are buried. This material is available for metamorphic reactions and will interact with rocks at the wet solidus, producing evolved rock compositions and volatile by-products (e.g. methane) that will contribute to the early atmospheres of these planets. Evidence of vertical transport in ancient Earth rocks has generally been attributed to subduction but heat-pipe advection provides a more global opportunity for such cycling.</p>

A Numerical Analysis of Gas Turbine Disks Incorporating Rotating Heat Pipes

2000 ◽  
Author(s):  
Y. Cao ◽  
J. Ling ◽  
R. Rivir ◽  
C. MacArthur
Keyword(s):  
Heat Pipe ◽  
Gas Turbine ◽  
Heat Pipes ◽  
High Heat ◽  
Thermal Dissipation ◽  
High Heat Flux ◽  
Heating And Cooling ◽  
Turbine Disks ◽  
Higher Temperature ◽  
Lower Temperature

Abstract Radially rotating heat pipes have been proposed for cooling gas turbine disks working at high temperatures. A disk incorporating the heat pipe would have an enhanced thermal dissipation capacity and a much lower temperature at the disk rim and dovetail surface. In this paper, extensive numerical simulations have been made for heat-pipe-cooled disks. Thermal performances are compared for the disks with and without incorporating the heat pipe at different heating and cooling conditions. The numerical results presented in this paper indicate that radially rotating heat pipes can significantly reduce the maximum and average temperatures at the disk rim and dovetail surface under a high heat flux working condition. In general, the maximum and average temperatures at the disk rim and dovetail surface could be reduced by above 250 and 150 degrees, respectively, compared to those of the disk without the heat pipe. As a result, a disk incorporating radially rotating heat pipes could alleviate temperature-related problems and allow a gas turbine to work at a much higher temperature.

Investigation of Loop Heat Pipe Startup Using Liquid Core Visualization

2008 ◽  
Author(s):  
B. P. d’Entremont ◽  
J. M. Ochterbeck
Keyword(s):  
Heat Pipe ◽  
Liquid Core ◽  
High Heat ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Two Phase ◽  
Buoyancy Driven Flows ◽  
Compensation Chamber ◽  
Fill Level ◽  
Heat Loads

In this investigation, a Loop Heat Pipe (LHP) evaporator has been studied using a borescope inserted through the compensation chamber into the liquid core. This minimally intrusive technique allows liquid/vapor interactions to be observed throughout the liquid core and compensation chamber. A low conductivity ceramic was used for the wick and ammonia as the working fluid. Results indicate that buoyancy driven flows, both two-phase and single-phase, play essential roles in evacuating excess heat from the core, which explains the several differences in performance between horizontal and vertical orientations of the evaporator. This study also found no discernable effect of the pre-start fill level of the compensation chamber on thermal performance during startup at moderate and high heat loads.

An Investigation of the Thermal Performance of a Novel Axial Grooved Heat Pipe

2012 ◽  
Vol 580 ◽  
pp. 223-226
Author(s):  
K.M. Yang ◽  
N.H. Wang ◽  
C.H. Jiang ◽  
L. Cheng
Keyword(s):  
Surface Tension ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Thermal Characteristics ◽  
High Heat ◽  
Input Power ◽  
Thermal Coefficient ◽  
Total Thermal Resistance ◽  
High Heat Transfer ◽  
Axial Temperature

Heat pipes are devices capable of very high heat transfer and have been widely used in many thermal management applications. An experimental investigation of thermal characteristics of heat pipe with axial ‘‘Ω”-shaped grooves was presented in this paper. The effects of angle of inclination and input power on thermal performance of heat pipe were investigated, the surface tension and gravity both impacted the fluid flow in heat pipe, and which one was dominating was analyzed. Experimental results indicate that the working temperature of heat pipe, the axial temperature differences and the maximum axial temperature differences increase when increasing the input heat flux. The total thermal resistances become smaller with the input power increasing, but become bigger with the angle of inclination increasing. And the trend of the thermal coefficient of heat pipe reverses that of the total thermal resistance. The influence of gravity on thermal performance is weaker than that of the surface tension.

Sector Rotating Heat Pipe With Interconnected Branches and Reservoir for Turbomachinery Cooling

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Brian Reding ◽  
Yiding Cao
Keyword(s):  
Experimental Study ◽  
Heat Pipe ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Practical Solution ◽  
Pipe System ◽  
Current Configuration ◽  
Cooling Technique

Heat pipe technology offers a possible cooling technique for structures exposed to high heat fluxes, as in turbomachinery such as compressors and turbines. However, in its current configuration as single heat pipes, implementation of the technology is limited due to the difficulties in manufacturability and costs. Hence, a study to develop a new radially rotating (RR) heat pipe system was undertaken, which integrates multiple RR heat pipes with a common reservoir and interconnected braches for a more effective and practical solution to turbomachinery cooling. Experimental study has shown that the integration of multiple heat pipe branches with a reservoir at the top is feasible.

Experimental study on a R134a loop heat pipe with high heat transfer capacity

2021 ◽  
Author(s):  
Changwu Xiong ◽  
Lizhan Bai ◽  
Hechao Li ◽  
Yuandong Guo ◽  
Yating Yu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Pipe ◽  
High Heat ◽  
Loop Heat Pipe ◽  
High Heat Transfer ◽  
Heat Transfer Capacity

Experimental Investigation of the Miniature Loop Heat Pipe With Flat Evaporator

2005 ◽  
Author(s):  
Randeep Singh ◽  
Aliakbar Akbarzadeh ◽  
Masataka Mochizuki ◽  
Thang Nguyen ◽  
Vijit Wuttijumnong
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Control ◽  
Capillary Forces ◽  
High Heat ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Wick Structure ◽  
Flat Evaporator ◽  
Heat Loads

Loop heat pipe (LHP) is a very versatile heat transfer device that uses capillary forces developed in the wick structure and latent heat of evaporation of the working fluid to carry high heat loads over considerable distances. Robust behaviour and temperature control capabilities of this device has enable it to score an edge over the traditional heat pipes. In the past, LHPs has been invariably assessed for electronic cooling at large scale. As the size of the thermal footprint and available space is going down drastically, miniature size of the LHP has to be developed. In this paper, results of the investigation on the miniature LHP (mLHP) for thermal control of electronic devices with heat dissipation capacity of up to 70 W have been discussed. Copper mLHP with disk-shaped flat evaporator 30 mm in diameter and 10 mm thickness was developed. Flat evaporators are easy to attach to the heat source without any need of cylinder-plane-reducer saddle that creates additional thermal resistance in the case of cylindrical evaporators. Wick structure made from sintered nickel powder with pore size of 3–5 μm was able to provide adequate capillary forces for the continuos circulation of the working fluid, and successfully transport heat load at the required distance of 60 mm. Heat was transferred using 3 mm ID copper tube with vapour and liquid lines of 60 mm and 200 mm length respectively. mLHP showed very reliable start up at different heat loads and was able to achieve steady state without any symptoms of wick dry-out. Tests were conducted on the mLHP with evaporator and condenser at the same level. Total thermal resistance, R total of the mLHP came out to be in the range of 1–4°C/W. It is concluded from the outcomes of the investigation that mLHP with flat evaporator can be effectively used for the thermal control of the electronic equipments with restricted space and high heat flux chipsets.

scholarly journals Experimental Study on Thermal Performance of a Bent Copper-Water Heat Pipe

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shuangshuang Miao ◽  
Jiajia Sui ◽  
Yulong Zhang ◽  
Feng Yao ◽  
Xiangdong Liu
Keyword(s):  
Heat Flux ◽  
Heat Pipe ◽  
Critical Heat Flux ◽  
Working Conditions ◽  
Thermal Performance ◽  
Heat Input ◽  
High Heat ◽  
High Heat Flux ◽  
Electronic Components ◽  
Copper Water

Vapor-liquid phase change is regarded as an efficient cooling method for high-heat-flux electronic components. The copper-water bent heat pipes are particularly suited to the circumstances of confined space or misplaced heat and cold sources for high-heat-flux electronic components. In this paper, the steady and transient thermal performance of a bent copper-water heat pipe is studied based on a performance test system. The effects of cooling temperature, working conditions on the critical heat flux, and equivalent thermal conductivity have been examined and analyzed. Moreover, the influences of heat input and working conditions on the thermal response of a bent heat pipe have also been discussed. The results indicate that the critical heat flux is enhanced due to the increases in cooling temperature and the lengths of the evaporator and condenser. In addition, the critical heat flux is improved by extending the cooling length only when the operating temperature is higher than 50°C. The improvement on the equivalent thermal by increasing the heating length is more evident than that by increasing cooling length. It is also demonstrated by the experiment that the bent copper-water heat pipe can respond quickly to the variation of heat input and possesses superior transient heat transfer performance.

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