• Title/Summary/Keyword: Entrainment Limitation

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Theoretical Analysis of Factors Affecting to Heat Transfer Limitation in Screen Mesh Wick Heat Pipe (스크린 메쉬윅 히트파이프의 열전달한계에 영향을 미치는 인자의 이론적 해석)

  • 이기우;노승용;박기호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.11
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    • pp.880-889
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    • 2002
  • The purpose of the present study is to examine the factors affecting the heat transfer limitations of screen mesh heat pipe for electronic cooling by theoretical analysis. Diameter of pipe was 6 mm, and mesh numbers are 50, 100, 150, 200 and 250 and water was selected as a working fluid. According to the change of mesh number, wick layer, inclination and saturation temperature, capillary pressure, pumping pressure, liquid friction coefficient in wick, vapor friction coefficient, capillary limitation, entrainment limitation, sonic limitation and boiling limitation we analyzed by theoretical design method of a heat pipe. As some results, the capillary limitation in small diameter of heat pipe is largely affected by mesh number and wick layer.

Performance improvement of wave plate mist eliminator through geometry modification (Wave plate 습분제거기의 형상 변경을 통한 성능 개선)

  • Jung-Hun, Noh;Min-Cheol, Cho;Seung-Jong, Lee
    • Particle and aerosol research
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    • v.18 no.4
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    • pp.97-107
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    • 2022
  • The geometry of popular wave plate type mist eliminator for the wet flue gas desulfurization process was improved, fabricated, and experimentally evaluated. A Mist eliminator is a type of inertial particle collector which collection efficiency is proportional to the velocity of the gas phase. However, as the amount of re-entrainment is also proportional to the gas phase velocity, there is a limitation for the gas phase flow rate. Re-entrainment is one of the most important issues in a mist eliminator and is likely to occur as the input of the liquid phase and flow rate of the gas phase increase. In order to resolve this problem, the projection angle of the improved mist eliminator is set to 30° from the conventional one while maintaining the cross-section. With low flow rate conditions, the modified mist eliminator showed a similar pressure drop and overall collection efficiency. However, with conditions in which re-entrainment is obviously occurring, the modified mist eliminator showed better performance in draining droplets than the conventional one. As a result, the modified mist eliminator showed higher overall collection efficiency.

Theoretical Analysis on the Heat Transport Limitation of a Sintered Metal Wick Heat Pipe (소결윅 히트파이프의 열수송 한계에 관한 이론적 해석)

  • Kim Keun-Bae;Kim Yoo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.4
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    • pp.16-25
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    • 2004
  • Theoretical analysis for predicting the heat transport limitation of a copper powder sintered wick heat pipe was performed. The heat pipe diameter was 8mm and water was used for working fluid. The particle diameter was classified by 5 different meshes, and each capillary pressures and heat transport limitations. thermal resistances were analyzed according to the operating temperatures, wick thicknesses and inclination angles, based on the effective capillary radius($r_c$), porosity($\varepsilon$), Permeability (K). The wick capillary limitation was increased according as the particle diameter and the wick thickness and the operating temperature were increased. As the porosity and the capillary radius were larger. then the heat transport limitation was higher. The thermal resistance was greatly increased according as the wick thickness was increased.