• Title/Summary/Keyword: 유하액막

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Effects of Non-Absorbable Gases on the Absorption Process of Aqueous LiBr Solution Film in a Vertical Tube (I) (수직관내 리튬브로마이드 수용액막의 흡수과정에 대한 비흡수가스의 영향)

  • Kim, Byeong-Ju;Lee, Chan-U
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.4
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    • pp.489-498
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    • 1998
  • Among the heat/mass exchange units composing an absorption system, the absorber, where the refrigerant vapor is absorbed into the liquid solution is the one least understood. In the present study, the effects of non-absorbable gas on the absorption process of aqueous lithium bromide solution falling film inside a vertical tube were experimentally investigated. In the range of film Reynolds number of 30 ~ 195, heat and mass transfer characteristics were investigated as a function of non-absorbable gas volumetric concentration, 0.2 ~ 20%. An increase of non-absorbable gas volumetric concentration degraded the mass transfer rate dramatically in the absorption process. The reduction of mass transfer rate was significant for the addition of small amount of non-absorbable gas to the pure vapor. At film Reynolds number of 130, an increase of non-absorbable gas concentration from 0.2 to 6.0% resulted in the decrease of mass transfer rate by 36% and 20% of non-absorbable gas by 59%. However the decrease of film Nusselt number with the increase of volumetric concentration of non absorbable gas was relatively smaller than the decrease of Sherwood number. Critical film Reynolds number was identified to exist for the maximum heat and mass transfer regardless of the volumetric concentration of non-absorbable gases.

Experimental Study on Heat Transfer Performance of Plate Type Absorber with Variation of Solution Flow Rate (용액유량에 따른 플레이트 흡수기의 흡수 열전달 특성 실험)

  • Moon, C.G.;Bang, G.S.;Kim, J.D.;Yoon, J.I.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1548-1553
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    • 2003
  • An experimental study of the absorption process of water vapor into a lithium bromide solution was performed. For the purpose of development of high performance absorption chiller/hater utilizing lithium bromide solution as working fluid, it is the most effective to improve the performance of absorber with the largest heat transfer area of the four heat exchangers. The experimental apparatus was composed of a plate type absorber which can increase the heat exchange area per unit volume to investigate more detail characteristics instead of the conventional type, horizontal tube bundle type. The size of plate absorbers were made for $0.4m{\times}0.6m$ and the design object of a refrigeration capacity was lRT. In this experiment, three kind plate absorbers which were flat plate, dimple plate and groove plate were used. The results were less than the design object values, that is, the refrigeration capacity was about $0.3{\sim}0.4RT$ and the overall heat transfer coefficient was $500{\sim}600kcal/m^2h^{\circ}C$ at the standard conditions.

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An experiment of the particle deposition on a circular cylinder in a laminar flow (원관 주위 유하 액막에 의한 관 외벽에서의 입자 부착에 대한 실험)

  • 정종수;이윤표;정기만;박찬우
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.2
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    • pp.113-119
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    • 2000
  • An experimental study has been carried out in order to investigate on a particle deposition on a circular cylinder surface. The present study is focused on the particulate fouling occurring in a heat exchanger for a seawater desalinization, in a laminar flow over circular cylindrical tubes. The objective is to investigate how NaCl concentration influences the $SiO2$ particle deposition on the surface of a glass circular cylinder. The NaCl concentration was changed from 0 g/L to 40 g/L. As the experimental results of $SiO2$ particle which is deposited on the glass circular cylinder surface showed, particle deposition rate per unit time increases rapidly with the increase of NaCl concentration between 0 g/L and 15 g/L. After the maximum of particle deposition rate was found at the NaCl concentration of 15 g/L, particle deposition rate remains unchanged or decreases gradually with the NaCl concentration from 15 g/L to 40 g/L. Also the $SiO2$ deposition rate of particles does not have serious variations with the position at present glass surface.

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The Experimental Study of Ice Thermal Storage for Falling Film Type - Sprint Coil Type - (스파이럴형 냉동코일을 사용한 유하액막식 빙축열조에서 열전달현상에 관한 실험적연구)

  • Lee, C.M.;Kim, D.H.;Cho, N.C.;Kim, I.G.;Park, S.R.;Choi, K.K.;Yim, C.S.
    • Solar Energy
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    • v.19 no.2
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    • pp.1-8
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    • 1999
  • The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

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