Investigation of Lightweight Space Radiator Design for Low and No Gravity Environments

2011 ◽  
Author(s):  
Virginia Bieger ◽  
Jian Ma
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Liquid Droplet ◽  
Radiation Heat Transfer ◽  
Construction Materials ◽  
Carbon Composite ◽  
Liquid Sheet ◽  
Working Fluid ◽  
Working Fluids ◽  
Fin Design

Space heat rejection is heavily relying on radiator subsystem, which is only depended on pure radiation heat transfer and typical convection is not available. Increased efficiency coupled with reduced mass is of strategic importance in space thermal system. This paper reviews the existing individual aspects of lightweight space radiator subsystem designs under low and no gravity environments, i.e. working fluids, fin design, or optimization, based on standard construction materials. In addition, new concept approaches using latest technologies and their challenges are also investigated in this study. Common designs include heat pipe, liquid sheet, and liquid droplet radiators, the latter two being more conceptual than functional. Most technological advances have been made in the materials of construction and optimization areas while using the traditional heat pipe design since 1960s. Carbon composites are the most promising material for construction, as they possess a good heat transfer rate while minimizing the weight of the system. Working fluids selection has more to do with the operational temperature range than the system design, though construction materials must be taken into account when selecting a working fluid. Fin design is the least reported on, but the general consensus is triangular fins are the best option for minimizing weight while increasing surface area for radiation. Based on the review of current research, the most promising design would be a carbon composite heat pipe with a working fluid of liquid water or ammonia and triangular fins.

Experimental Investigation and Performance Evaluation of a Multi Turn Closed Loop Pulsating Heat Pipe

2014 ◽  
Vol 592-594 ◽  
pp. 1554-1558 ◽  
Author(s):  
N. Narendra Babu ◽  
Rudra Naik
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Heat Pipe ◽  
Closed Loop ◽  
Experimental Result ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Working Fluids

Pulsating heat pipe (PHP) is a passive heat transfer device, which transfers heat from one region to another with exceptional heat transfer capacity. It utilizes the latent heat of vaporization of the working fluid as well as the sensible heat. As a result, the effective thermal conductivity is higher than that of the conductors. An experimental study on three turn closed loop pulsating heat pipe with three different working fluids viz., Acetone, Methanol, Heptane and distilled water were employed. The PHP is made up of brass material with an inner diameter of 1.95mm, with a total length of 1150 mm for different fill ratios (FR) was employed .The PHP is tested for the thermal resistance and the heat transfer coefficient. The experimental result strongly demonstrates that acetone is a better working fluid among the working fluids considered in terms of higher heat transfer coefficient and lower thermal resistance.

scholarly journals PERFORMANCE OF HEAT PIPE FOR DIFFERENT WORKING FLUIDS AND FILL RATIOS

2011 ◽  
Vol 41 (2) ◽  
pp. 96-102 ◽  
Author(s):  
A. K. Mozumder ◽  
A. F. Akon ◽  
M. S. H. Chowdhury ◽  
S. C. Banik
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Heat Pipe ◽  
Thermal Capacity ◽  
Working Fluid ◽  
Working Fluids ◽  
Overall Heat Transfer Coefficient ◽  
Lower Temperature

An attempt is made to design, fabricate and test a miniature heat pipe with 5 mm diameter and 150 mm length with a thermal capacity of 10 W. Experiments were conducted with and without working fluid for different thermal loads to assess the performance of heat pipe. The working fluids chosen for the study were same as those commonly used namely, water, methanol and acetone. The temperature distribution across the heat pipe was measured and recorded using thermocouples. The performance of the heat pipe was quantified in terms of thermal resistance and overall heat transfer coefficient. The amount of liquid filled was varied and the variation of the performance parameters for varying liquid inventory is observed. Finally, optimum liquid fill ratio is identified in terms of lower temperature difference and thermal resistance and higher heat transfer coefficient. The data reported in this study will serve as a good database for the researchers in this field. Overall heat transfer coefficient of the Miniature heat pipe is found to be the maximum for the Acetone as working fluid.DOI: http://dx.doi.org/10.3329/jme.v41i2.7473

scholarly journals Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (2S2) ◽  
pp. 143-147 ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Hot Water ◽  
Working Fluid ◽  
Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

scholarly journals Sodium-Potassium Alloy Heat Pipe under Geyser Boiling Experimental Study: Heat Transfer Analysis

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7582
Author(s):  
Hongzhe Zhang ◽  
Fang Ye ◽  
Hang Guo ◽  
Xiaoke Yan
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heating Power ◽  
Heat Transfer Analysis ◽  
Working Fluid ◽  
Condenser Section ◽  
Sodium Potassium ◽  
Alloy Heat ◽  
Convection Cooling ◽  
Boiling Mode

In the geyser boiling mode, the working fluid state is divided into a boiling process and a quiet process, and the sodium-potassium (Na-K) alloy heat pipe can discontinuously transfer heat at each boiling. The overheating of the liquid working fluid at the bottom causes short-term boiling and forms slug bubble, the strong condensing ability quickly conducts heat from the evaporator section. And geyser boiling can occur before the working fluid forms continuous flow, so it transfers more heat at lower temperatures than natural convection cooling. In this study, the heat transfer process of a Na-K alloy heat pipe with forced convection cooling under different heating power was experimental studied. The geyser boiling mode can make the Na-K alloy heat pipe work below 650 °C and reduce the start-up time. In the process of geyser boiling, the heat transfer quantity was increased by the boiling frequency and the amount of vapor produced in a single boiling. The boiling temperature had no obvious change with the increased of heating power, and the condenser section temperature increased with the heating power.

scholarly journals The Influence of Loop Heat Pipe Evaporator Porous Structure Parameters and Charge on Its Effectiveness for Ethanol and Water as Working Fluids

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7029
Author(s):  
Krzysztof Blauciak ◽  
Pawel Szymanski ◽  
Dariusz Mikielewicz
Keyword(s):  
Porous Structure ◽  
Pore Size ◽  
Heat Pipe ◽  
Capillary Pressure ◽  
Pressure Difference ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Working Fluids ◽  
Integral Characteristics ◽  
Sintered Stainless Steel

This paper presents the results of experiments carried out on a specially designed experimental rig designed for the study of capillary pressure generated in the Loop Heat Pipe (LHP) evaporator. The commercially available porous structure made of sintered stainless steel constitutes the wick. Three different geometries of the porous wicks were tested, featuring the pore radius of 1, 3 and 7 µm. Ethanol and water as two different working fluids were tested at three different evaporator temperatures and three different installation charges. The paper firstly presents distributions of generated pressure in the LHP, indicating that the capillary pressure difference is generated in the porous structure. When installing with a wick that has a pore size of 1 μm and water as a working fluid, the pressure difference can reach up to 2.5 kPa at the installation charge of 65 mL. When installing with a wick that has a pore size of 1 μm and ethanol as a working fluid, the pressure difference can reach up to 2.1 kPa at the installation charge of 65 mL. The integral characteristics of the LHP were developed, namely, the mass flow rate vs. applied heat flux for both fluids. The results show that water offers larger pressure differences for developing the capillary pressure effect in the installation in comparison to ethanol. Additionally, this research presents the feasibility of manufacturing inexpensive LHPs with filter medium as a wick material and its influence on the LHP’s thermal performance.

scholarly journals The effect of operating parameters on the heat transfer in the heat pipe

2021 ◽  
Vol 2119 (1) ◽  
pp. 012088
Author(s):  
A. A. Litvintceva ◽  
N. I. Volkov ◽  
N. I. Vorogushina ◽  
V. A. Moskovskikh ◽  
V. V. Cheverda
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Temperature Difference ◽  
Heat Pipes ◽  
Working Fluid ◽  
Operating Parameters ◽  
Temperature Stabilization ◽  
Ir Camera ◽  
Fluid Properties

Abstract Heat pipes are a good solution for temperature stabilization, for example, of microelectronics, because these kinds of systems are without any moving parts. Experimental research of the effect of operating parameters on the heat transfer in a cylindrical heat pipe has been conducted. The effect of the working fluid properties and the porous layer thickness on the heat flux and temperature difference in the heat pipe has been investigated. The temperature field of the heat pipe has been investigated using the IR-camera and K-type thermocouples. The data obtained by IR-camera and K-type thermocouples have been compared. It is demonstrated the power transferred from the evaporator to the condenser is a linear function of the temperature difference between them.

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