scholarly journals The Problem of Freezing of Copper Water Heat Pipes

2021 ◽  
Author(s):  
Subas Acharya ◽  
Valeria Barra ◽  
Dean Duffy ◽  
David A. Edwards ◽  
Vrushaly Singlot
Keyword(s):  
Water Vapor ◽  
Pipe Wall ◽  
Heat Pipes ◽  
Electronic Components ◽  
Pipe Failure ◽  
Copper Water

To cool electronic components of spacecraft, engineers are considering the use of heat pipes, which are sealed copper pipes containing an annular copper wick saturated with water. Water vapor from the hot end travels to the cold end, where it condenses in the wick and flows back to the hot end. In space, the cold end can freeze the water inside, which can cause two modes of pipe failure. First, if water accumulates in the cold end, then freezes, it can burst the pipe wall. Second, with the repeated expansion of the freezing water, pores in the copper wick can enlarge, reducing the speed of transport and hence the heat pipe's effectiveness. In this work we will examine both types of failures, with an eye toward establishing tolerances below which we expect the wick to remain functional.

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.

Effect of O2 on copper-water vapor interaction near critical point

2006 ◽  
Vol 41 (5) ◽  
pp. 1571-1577 ◽  
Author(s):  
Y. Jin ◽  
H. Kato ◽  
I. R. Korablova ◽  
K. Ioku ◽  
N. Yamasaki
Keyword(s):  
Water Vapor ◽  
Critical Point ◽  
Copper Water

An Experimental Study of Micro Radially Rotating Heat Pipes With Water as the Working Fluid

2008 ◽  
Author(s):  
Yiding Cao ◽  
Jian Ling
Keyword(s):  
Heat Pipe ◽  
Thermal Conductance ◽  
Heat Pipes ◽  
Working Fluid ◽  
Rotating Speed ◽  
Copper Water ◽  
High Pressure Compressor ◽  
Potential Applications ◽  
Inner Diameter ◽  
Pressure Compressor

In this study, three copper-water rotating heat pipes having inner diameters of 1.5, 2, and 3 mm, respectively, are fabricated and tested. The effectiveness of the copper-water heat pipe is first validated by comparing its performance with that of a copper bar having the same inner and outer diameters. The heat pipes are then tested to prove their reliability, high effective thermal conductance, and critical working limitation. The experimental data shows that the critical limitation may be reached when the inner diameter of the heat pipe is below 1.5 mm under the condition of a low rotating speed. The tests of these water heat pipes could also explore potential applications of radially rotating heat pipes in disks/blades of a high-pressure compressor.

Steel-Cylinder Yielding Analysis of PCCP with Broken Wires

2012 ◽  
Vol 503-504 ◽  
pp. 819-823 ◽  
Author(s):  
Ri You ◽  
Hong Bo Gong
Keyword(s):  
Prestressed Concrete ◽  
Pipe Wall ◽  
Nonlinear Finite Element ◽  
Simplified Model ◽  
Pipe Failure ◽  
Prestress Loss ◽  
Element Analysis ◽  
Steel Cylinder ◽  
Limit Stress ◽  
Prestressed Concrete Cylinder Pipe

The prestressing wires of prestressed concrete cylinder pipe (PCCP) provide pipe wall with compressive stress to resist internal pressure. Broken wires may cause yielding of steel cylinder and increase the risk of pipe failure with time. In order to reveal the mechanism of steel-cylinder yielding in PCCP with broken wires, a simplified model is developed and the maximum number of broken wires to preclude exceeding limit stress in steel cylinder can be determined conveniently by the equations derived in this paper. Verification analysis shows that the solution of simplified model agrees well with that of nonlinear finite element analysis. By comparing the calculated maximum number of broken wires with the detected actual number of broken wires, steel-cylinder yielding in prestress loss zone can be predicted, thus aiding condition assessment of PCCP

scholarly journals Effect of heat pipe failure on performance of residual heatremoval system with heat pipe for small lead-based reactor

2021 ◽  
Vol 248 ◽  
pp. 01021
Author(s):  
Chongju Hu ◽  
Hongyan Wang ◽  
Bo Wu ◽  
Xiuxiang Zhang ◽  
Pinghua Zhang
Keyword(s):  
Heat Pipe ◽  
Waste Heat ◽  
Heat Removal ◽  
Heat Pipes ◽  
Normal Operation ◽  
Pipe Failure ◽  
The Core ◽  
External Power ◽  
Heat Removal System ◽  
Removal System

Heat pipe have the characteristics of high thermal conductivity, high safety performance, without external power, etc. In this paper, The numerical simulation CFD software FLUENT is used to study the thermal-hydraulic characteristics performance of heat pipe waste heat removal system with heat pipe for lead-based reactor under normal conditions and Station-Black-Out (SBO) with partial heat pipes damage respectively. Results showed that heat pipes promote heat transfer in the reactor and reduced the temperature of the fluid around the reactor during normal operation; Heat in the core could be removed smoothly by the PRHRS during SBO accident without heat pipe damage ; and when the proportion of failed heat pipes is less than 50% during SBO accident , the PRHRS could still ensure safe operation of the reactor and the distribution of failed heat pipes in the reactor results the core temperature variation by less than 5 K.

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