Uniformity of liquid film distribution in helical channel of single screw expander

doi:10.11949/0438-1157.20201552

Abstract

Abstract:

The evenness distribution of liquid film in helical channel is very important to reduce gas leakage, and ensure the efficient of the expander. In this paper, the numerical VOF model is used to analyze the influence of helical channel structure parameters on the film thickness evenness distribution in y direction. According to the experimental data of the two-phase annular flow in the helical channel obtained in the previous experiment, the accuracy of the numerical model is verified, and the evolution process of the liquid film distribution in the helical channel is revealed. It is pointed out that the influence of torsion effect on the liquid phase distribution of the helical channel is negligible as η=0.90β, and the thickness of the liquid film on the outside of the helical channel is evenness in the y direction. Theoretical analysis of dimensionless pitches and curvature ratios on the change of liquid film thickness shows that the evenness index of liquid film thickness increases obviously with the increase of the dimensionless pitch, and decreases with the increase of the curvature ratio.

Key words: helical rectangular channel, VOF model, liquid film, evenness index

摘要：

螺旋槽道内均匀分布的液膜厚度对减小气体泄漏，保证膨胀机高效稳定运行至关重要。本文采用VOF两相流数值模型，主要探讨螺旋槽道结构参数对y方向液膜膜厚均匀度分布的影响规律。根据前期试验获得的螺旋槽内两相环状流的试验数据验证了数值模型的准确性，给出了入射角度η=0.90β时，液膜沿螺旋槽道内的演变过程。可以看出，当η=0.90β时，扭转效应对螺旋槽液相分布的影响基本可以忽略不计，螺旋槽外侧液膜厚度沿y方向基本呈均匀分布。理论分析不同无量纲节距和曲率比对y方向液膜厚度均匀度的影响规律，结果表明：随着螺旋槽道无量纲节距的增大，液膜厚度均匀度有所增加，随着曲率比的增大，液膜厚度均匀度降低。

关键词: 螺旋槽道, VOF模型, 液膜, 均匀度

CLC Number:

O 359

LIU Xianfei, WANG Heng, WANG Fang, LI Zhiqiang, ZHU Caixia, ZHANG Haofei. Uniformity of liquid film distribution in helical channel of single screw expander[J]. CIESC Journal, 2021, 72(S1): 336-341.

刘献飞, 王恒, 王方, 李志强, 朱彩霞, 张浩飞. 单螺杆膨胀机螺旋槽道内液膜分布均匀特性[J]. 化工学报, 2021, 72(S1): 336-341.

Figures/Tables 7

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序号	当量直径, d/mm	螺旋直径, D/mm	节距, H/mm	曲率比, γ	无量纲螺距,λ
1	22.5	195	306.31	0.115	0.5
2	22.5	175	274.89	0.129	0.5
3	22.5	155	243.47	0.145	0.5
4	22.5	195	428.83	0.115	0.7
5	22.5	195	551.35	0.115	0.9

序号	当量直径, d/mm	螺旋直径, D/mm	节距, H/mm	曲率比, γ	无量纲螺距,λ
1	22.5	195	306.31	0.115	0.5
2	22.5	175	274.89	0.129	0.5
3	22.5	155	243.47	0.145	0.5
4	22.5	195	428.83	0.115	0.7
5	22.5	195	551.35	0.115	0.9

节点比例	节点数	液相占有率	最小液膜厚度/mm	平均液膜厚度/mm
0.0015	75104	0.070443	0.44434	0.5294
0.0012	152478	0.071532	1.03851	1.1937
0.001	237162	0.071985	1.12512	1.2839
0.00095	291403	0.071999	1.12536	1.2871

节点比例	节点数	液相占有率	最小液膜厚度/mm	平均液膜厚度/mm
0.0015	75104	0.070443	0.44434	0.5294
0.0012	152478	0.071532	1.03851	1.1937
0.001	237162	0.071985	1.12512	1.2839
0.00095	291403	0.071999	1.12536	1.2871

气相流率/ (kg/s)	液相流率/ (kg/s)	试验液膜厚度/mm	试验液膜厚度/mm	相对误差/%
0.0882	0.00685	2.0031	2.079	3.79
0.1519	0.00735	1.9266	1.986	3.08
0.24989	0.00806	1.8192	1.866	2.57
0.31849	0.00935	1.6461	1.682	2.18