Numerical simulation for flow condensation of methanol in horizontal tube

doi:10.11949/0438-1157.20241090

Abstract

Abstract:

Numerical simulations were conducted to study the flow condensation process of methanol in horizontal tube. This study examines the impact of vapor quality on methanol condensation heat transfer and pressure drop characteristics under varying mass flux conditions. The investigation also elucidates the flow pattern transitions and liquid film properties during the condensation process. The results show that the heat transfer coefficient reaches a peak value in the range of dryness of 0.87—0.95, and the peak value corresponds to an increase in dryness from 0.87 to 0.95 when the mass flux is 25—75 kg·m^-²·s^-¹. The pressure gradient increases with increasing mass flow rate and vapor quality; however, when the vapor quality exceeds 0.9, the pressure drop gradient decreases with further increases in vapor quality. The primary flow patterns during the condensation process under the simulated conditions are annular/mist flows and stratified/wave flows. During the flow process, the local minimum thickness of the liquid film is observed at θ=90°. An increase in mass flux improves the uniformity of the liquid film distribution.

Key words: methanol, condensation, numerical simulation, heat transfer, pressure drop, liquid film, multiphase flow

摘要：

采用数值模拟研究了甲醇在水平圆管内的流动冷凝过程，探究了不同质量通量下蒸汽干度对甲醇冷凝换热及压降特性的影响，分析了冷凝过程中的流型转换和液膜特性。结果表明，在干度为0.87~0.95时传热系数达到峰值，质量通量为25~75 kg·m^-2·s^-1时，峰值对应干度从0.87增加到0.95；压力梯度随着质量流量、干度的增加而增加，但干度大于0.9时，压降梯度随着干度的增加而减小。模拟工况下甲醇冷凝流动过程主要流型为雾状流/环状流以及波状流/分层流。截面液膜厚度在θ =90°处达到局部最小值，质量通量的增加提升了液膜分布均匀性。

关键词: 甲醇, 冷凝, 数值模拟, 传热, 压降, 液膜, 多相流

CLC Number:

TK 124

Jiangyue GUO, Shoujin CHANG, Haitao HU. Numerical simulation for flow condensation of methanol in horizontal tube[J]. CIESC Journal, 2025, 76(6): 2580-2588.

郭江悦, 常守金, 胡海涛. 水平管内甲醇流动冷凝数值模拟研究[J]. 化工学报, 2025, 76(6): 2580-2588.

Figures/Tables 9

Fig.1 Geometric model diagram

Fig.2 Results of mesh independent verification

Fig.3 Comparison of numerical heat transfer coefficients and pressure gradients with empirical correlations

Fig.4 Heat transfer coefficient versus vapor quality at different mass fluxes

Fig.5 Pressure drop versus vapor quality at different mass fluxes

Fig.6 Flow patterns of condensation process at different mass fluxes

Fig.7 Comparison of simulated flow pattern data with flow pattern maps of Breber

Fig.8 Gas-liquid interface in circular tubes at different vapor quality

Fig.9 The variation of liquid film thickness (δ) with angle(θ) in the channel(θ=0° represents the bottom of the pipe and θ=180° represents the top of the pipe)

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