• Title/Summary/Keyword: Noncondensable gas

Search Result 28, Processing Time 0.16 seconds

Noncondensable Gas Effects on the Marangoni Convection (마랑고니 대류에 미치는 불응축성가스의 영향)

  • Rie, D.H.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.8 no.4
    • /
    • pp.510-518
    • /
    • 1996
  • The study presents experimental and theoretical analysis focusing on the infulence of a noncondensable gas upon the absorption enhancement that is obtained by Marangoni convection generated by the addition of the surfactant. The shadowgraph method is adopted in this visualization. As a result of absorption phenomena with shadowgraph photos, the different patterns of Marangoni convection cells are observed in accordance with the various amounts of noncondensable gas. Furthermore, non dimensional number K(Ma/Ra) is introduced to calculate the value of surface tension difference theoretically for the comparison with the various amount of non condensable gas in absorber.

  • PDF

Condensation Heat Transfer for the R-11 Superheated Vapor with and without Noncondensable Gas (R-11의 응축열전달에 미치는 부응축가스 및 과열의 영향)

  • CHO Kwon-Ok;KUM Jong-Soo;OH HOO-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.18 no.2
    • /
    • pp.85-93
    • /
    • 1985
  • An experimental investigation on condensing heat transfer for the Refrigerant-11 superheated vapor during condensation on the 40 mm O.D by 75 mm long horizontal tube is carried out under the various conditions of air contents as noncondensable gas, condensing pressure, and coolant temperature. The data span a refrigerant flow range from 23 to 63 kg/h and weight fractions of noncondensable gas range from 0 to $15\%$. The comparisons are made using data obtained by the authors and further data obtained from other sources. The characteristics of the condensing heat transfer of refrigerant superheated vapor with and without noncondensable gas flowing horizontally are revealed experimentally, and on the basis of the data obtained, correlations for predicting heat transfer coefficient during condensation on the tube are proposed.

  • PDF

A study on effect of heat transfer of condensation including noncondensable gas over a flat plate (불응축가스가 평판위 응축열전달에 미치는 영향에 관한 연구)

  • 양대일;정형호
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.24 no.1
    • /
    • pp.25-30
    • /
    • 2000
  • In present paper, mass transfer over a flat plate with film condensation including noncondesable gas is analyzed with the help of similarity methods. Couette flow was assumed in liquid film and boundary-layer approximation was used in the ambient flow. Governing equations were transformed into the ordinary differential equtions by the similarity methods. Runge-Kutta and shooting method were used in order to fine the effect of mass transfer on the velocity and concentrations at the liquid-vapor interface.

  • PDF

Numerical Study of Gap Size Ratio Effect for Noncondensable Gas Ventilation in Condensers (응축기의 비응축 가스 배출 타입에 따른 틈 간격 비율의 영향에 대한 수치적 연구)

  • Je, Jun-Ho;Kim, Soo-Jea;Choi, Chi-Woong;Kim, Moo-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.36 no.1
    • /
    • pp.67-74
    • /
    • 2012
  • A numerical analysis was carried out to estimate the effect of the gap size ratio on the performance of condensers under noncondensable gas ventilation using the porous medium approach (PMA). In the PMA, the details of the tube bundle in the condenser are considered to be those of a porous medium, and the flow resistance term is added in the momentum equation. Three-dimensional analysis of the condensation for a McAllister condenser was conducted with the PMA using Fluent and user-defined functions (UDFs). The gap size effect on the condensation was negligible under pure steam conditions. However, the gap size effect was dominant in condensation with noncondensable gas and external venting. As the gap size decreased, the condensation rate increased for noncondensable gas in an external venting system.

Assessment of Two Wall Film Condensation Models of RELAP5/MOD3.2 in the Presence of Noncondensable Gas in a Vertical Tube

  • Park, Hyun-Sik;No, Hee-Cheon;Bang, Young-Seok
    • Nuclear Engineering and Technology
    • /
    • v.31 no.5
    • /
    • pp.465-475
    • /
    • 1999
  • The objective of the present work is to assess the analysis capability of two wall film condensation models, the default and the alternative models, of RELAP5/MOD3.2 on condensation experiments in the presence of noncondensable gas in a vertical tube of PCCS of CP-1300. In the calculation of a base case the default model of RELAP5/MOD3.2 under-predicts the heat transfer coefficients, and Its alternative model over-predicts them throughout the condensing tube, Also, both models over-predict the void fractions. The nodalization study shows that the variation of the node number does not change both modeling results of RELAP5/MOD3.2 Sensitivity study for varying input parameters shows that the inlet steam-air mixture flow rate, the inlet air mass fraction, and the inlet saturated steam temperature give significant changes of their heat transfer coefficients Run statistics show that the grind time of the default model is always higher than that of the alternative model by about 23%.

  • PDF

Noncondensable gas's influence in waster vapor absorption accompanying interfacial disturbance into aqueous solution of LiBr

  • Dong-Ho RIE;Keun-Oh Lee
    • Journal of the Korean Society of Safety
    • /
    • v.7 no.2
    • /
    • pp.63-70
    • /
    • 1992
  • The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass%) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass%). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume%) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

  • PDF