Experiment investigation of two-phase flow pattern transition and frictional pressure drop of R600a in a horizontal tube

被引：0
|
作者：
Yang Z. [1 ,2 ]
Gong M. [1 ]
Chen G. [1 ]
Zou X. [1 ]
Zhuang X. [1 ,2 ]
Song Q. [1 ,2 ]
Shen J. [1 ]
机构：
[1] Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing
[2] University of Chinese Academy of Sciences, Beijing
来源：
Gong, Maoqiong (gongmq@mail.ipc.ac.cn) | 2018年 / Chinese Academy of Sciences卷 / 63期
关键词：
Correlation; Flow pattern transition; Friction pressure drop; R600a;
D O I：
10.1360/N972017-00587
中图分类号：
学科分类号：
摘要：
With the growing concern of environment problems, there are urgent demands for environment-friendly refrigerants in the refrigeration industry. As a natural refrigerant, R600a not only has zero ozone depletion potential and quite low global warming potential, but also has better cooling performance than other refrigerants. Due to its good cooling performance and environment-friendly characteristics, R600a has been used as an alternative refrigerant in heat transfer applications such as refrigerators, freezers, and heat pumps. It is known that accurate prediction of two phase flow pattern transition and frictional pressure drop of R600a in a horizontal tube play an important role in design and optimization of refrigerators, freezers, and heat pumps. According to this issue, a detailed experimental study was carried out to investigate the two-phase flow pattern transition and frictional pressure drop characteristics of R600a in a smooth horizontal tube with an inner diameter of 6 mm. The experiments were performed at conditions covering saturation temperature from 282.4 to 304 K, mass fluxes from 67 to 194 kg/(m2 s). Based on a high speed camera, four main flow regimes can be observed: plug flow, stratified-wavy flow, slug flow and annular flow. The flow map of R600a has been drawn and comparisons between the experimental data of flow patterns and transition lines in the literature have been made. The results showed that with the increase of mass flux, the inception of the annular flow regime occurs earlier. The intermittent flow regime takes place over a narrow range of vapor quality and annular flow regime occupies a wide range of vapor quality. In addition, the trend of Barbieri and Ong and Thome I/A transitions lines are consistent with the experimental data. However, both of them overestimate the inception of the annular flow regime. After taking the influence of vapor inertia, liquid viscous and surface tension forces into account, a modified Weber number We* has been introduced to the new flow pattern transition model. Based on the relationship of Xtt and We*, a new correlation has been proposed and it can well fit with the experimental data of flow pattern. Furthermore, a detailed discuss of frictional pressure drop of annular flow and non-annular flow has been made. The results indicated that frictional pressure drop increases with the increases of vapor quality. The tendency of frictional pressure drop presents different the changing laws in different flow regime. The frictional pressure drop increases slowly in the non-annular flow regime while it increases rapidly when the flow pattern turns into the annular flow regime. The reason is that the vapor-phase pressure drop often dominates the total two-phase frictional pressure drop. The annular flow regime owns higher void fraction than the non-annular flow regime. Nine classic prediction correlations of pressure drop were evaluated and the results showed that the correlation of Grönnerud and Muller-Steinhagen and Heck give the best fit to the experimental frictional pressure drop of annular flow and non-annular flow with a mean absolute relative deviation of 38.5% and 19.7% respectively. © 2018, Science Press. All right reserved.
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页码：92 / 107
页数：15
相关论文
共 28 条
  • [1] Yan G., Cui C., Yu J., Energy and exergy analysis of zeotropic mixture R290/R600a vapor-compression refrigeration cycle with separation condensation, Int J Refrigeration, 53, pp. 155-162, (2015)
  • [2] Ribatski G., Thome J.R., Two-phase flow and heat transfer across horizontal tube bundles-A review, Heat Transfer Eng, 28, pp. 508-524, (2007)
  • [3] Rollmann P., Spindler K., A new flow pattern map for flow boiling in microfin tubes, Int J Multiphas Flow, 72, pp. 181-187, (2015)
  • [4] Xu Y., Fang X., A new correlation of two-phase frictional pressure drop for condensing flow in pipes, Nucl Eng Des, 263, pp. 87-96, (2013)
  • [5] Wang S., Gong M.Q., Chen G.F., Et al., Two-phase frictional pressure drop for propane in a horizontal tube (in Chinese), J Eng Thermophys, 34, pp. 2155-2158, (2013)
  • [6] Nasr M., Akhavan-Behabadi M.A., Momenifar M.R., Et al., Heat transfer characteristic of R-600a during flow boiling inside horizontal plain tube, Int Commun Heat Mass, 66, pp. 93-99, (2015)
  • [7] Kattan N., Thome J., Favrat D., Flow boiling in horizontal tubes: Part 1-development of a diabatic two-phase flow pattern map, J Heat Transf, 120, pp. 140-147, (1998)
  • [8] Dalkilic A.S., Agra O., Teke I., Et al., Comparison of frictional pressure drop models during annular flow condensation of R600a in a horizontal tube at low mass flux and of R134a in a vertical tube at high mass flux, Int J Heat Mass Tran, 53, pp. 2052-2064, (2010)
  • [9] Chen I.Y., Yang K.S., Chang Y.J., Et al., Two-phase pressure drop of air-water and R-410A in small horizontal tubes, Int J Multiphas Flow, 27, pp. 1293-1299, (2001)
  • [10] Wen M.Y., Ho C.Y., Jang J.K., Boiling heat transfer of refrigerant R-600a/R-290-oil mixtures in the serpentine small-diameter U-tubes, Appl Therm Eng, 27, pp. 2353-2362, (2007)
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