摇摆对TFE-TEGDME降膜吸收影响的可视化实验研究
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摘要
本文搭建以TFE-TEGDME溶液为制冷工质对的摇摆吸收式制冷实验台,对竖直管降膜吸收器进行可视化实验研究。静止状态下实验表明:当溶液质量流量为0.1～0.2 kg/min时,液膜呈层流和单色波状态;当流量为0.5 kg/min和0.8 kg/min时,液膜表面出现稳定波状流与合并波状流;当质量流量为1.2 kg/min时,液膜出现脱落现象。在不同波形下吸收器的吸收效果差别很大。摇摆状态下实验表明:随着摇摆幅度的增大或摇摆周期的减小,液膜受到的扰动越大,当摇摆幅度达到15°或摇摆周期达到4 s时将出现合并波状流和脱落现象;在同一个摇摆幅度和周期下,液膜在摆幅边缘受到扰动较大,在摆幅中间流动较为平缓;当溶液质量流量为0.28 kg/min时,在摇摆幅度为8°或摇摆周期为10 s时系统COP最大,而当质量流量为0.14 kg/min时,COP峰值出现在摇摆幅度10°或摇摆周期8 s时,同时说明溶液质量流量更大时液膜受到摇摆的扰动就更大。
In this study, a swing absorption refrigeration system with 2,2,2-trifluoroethanol/tetraethylene glycol dimethyl ether(TFE-TEGDME) solution as the refrigerant pair was built to observe the vertical tube falling film absorber. Experiments in the stationary state showed that when the mass flow rate was 0. 1-0. 2 kg/min, the liquid film was in a laminar and monochromatic wave state; when the mass flow rate was 0. 5 kg/min and 0. 8 kg/min, the liquid film appeared to be a quasi-sine wave and merging wave flow, respectively; when the mass flow rate was 1. 2 kg/min, the liquid film partly fell off. The absorption effect depends heavily on the surface wave type. The experimental results in the swing state showed that the perturbation on the liquid film will increase with increasing swing amplitude or a decreasing swing period. When the swing amplitude is 15° or the period is 4 s, the liquid film appears to be a merging wave or falls off from the wall of the tube. Under a fixed swing amplitude and period, the perturbation on the film is greater at the edge of the swing, whereas the flow is smoother at the middle of the swing. When the mass flow rate is 0. 28 kg/min, the coefficient of performance(COP) of the system reaches the maximum at the swing amplitude of 8° or a period of 10 s. However, the COP will reach the maximum at a swing amplitude of 10° or a period of 8 s when the mass flow rate is 0. 14 kg/min. The results also showed that when the flow rate is higher, the perturbation of the swing is greater.
In this study, a swing absorption refrigeration system with 2,2,2-trifluoroethanol/tetraethylene glycol dimethyl ether(TFE-TEGDME) solution as the refrigerant pair was built to observe the vertical tube falling film absorber. Experiments in the stationary state showed that when the mass flow rate was 0. 1-0. 2 kg/min, the liquid film was in a laminar and monochromatic wave state; when the mass flow rate was 0. 5 kg/min and 0. 8 kg/min, the liquid film appeared to be a quasi-sine wave and merging wave flow, respectively; when the mass flow rate was 1. 2 kg/min, the liquid film partly fell off. The absorption effect depends heavily on the surface wave type. The experimental results in the swing state showed that the perturbation on the liquid film will increase with increasing swing amplitude or a decreasing swing period. When the swing amplitude is 15° or the period is 4 s, the liquid film appears to be a merging wave or falls off from the wall of the tube. Under a fixed swing amplitude and period, the perturbation on the film is greater at the edge of the swing, whereas the flow is smoother at the middle of the swing. When the mass flow rate is 0. 28 kg/min, the coefficient of performance(COP) of the system reaches the maximum at the swing amplitude of 8° or a period of 10 s. However, the COP will reach the maximum at a swing amplitude of 10° or a period of 8 s when the mass flow rate is 0. 14 kg/min. The results also showed that when the flow rate is higher, the perturbation of the swing is greater.
引文
[1] 姚普明, 陈秋芳. TFE/NMP、TFE/E181、NH3/H2O、H2O/LiBr等工质对(系)性能分析、比较评价[J]. 冷藏技术, 1996, 18(2):37-42. (YAO Puming, CHEN Qiufang, Performance analysis and comparison evaluation of working fluids TFE/NMP, TFE/E181, NH3/H2O, H2O/LiBr[J]. Journal of Refrigeration Technology, 1996, 18(2):37-42. )
[2] 张莉, 徐士鸣. TFE-H2O-TEGDME三元工质热物性参数表达式[J]. 大连理工大学学报, 2005, 45(4): 531-536. (ZHANG Li, XU Shiming, Representations of thermodynamic property of ternary working fluid TFE-H2O-TEGDME[J]. Journal of Dalian University of Technology, 2005, 45(4): 531-536. )
[3] XU Shiming, LIU Yanli, ZHANG Li. Performance research of self regenerated absorption heat transformer cycle using TFE-NMP as working fluids[J]. International Journal of Refrigeration, 2001, 24(6): 510-518.
[4] BAEHR H D, KLOBASA F, SCHARF R. Vapor pressure and liquid and gas densities of 2,2,2-trifluoroethanol[J]. International Journal of Thermophysics, 1989, 10(3):577-589.
[5] 丁帆. 摇摆条件下吸收式制冷机性能的实验研究[D]. 大连:大连海事大学, 2014. (DING Fan. Experimental research on performance of absorption chillers in the case of swing movement[D]. Dalian: Dalian Maritime University, 2014. )
[6] 张天骄. 摇摆对TFE/TEGDME吸收式制冷性能影响的实验研究[D]. 大连:大连海事大学, 2016. (ZHANG Tianjiao. Experiment study on TFE/TEGDME absorption refrigeration performance under swing conditions[D]. Dalian: Dalian Maritime University, 2016. )
[7] STEPHAN K, HENGERER R. Heat transformation with the ternary working fluid TFE-H2O-E181[J]. International Journal of Refrigeration, 1993, 16(2):120-128.
[8] GENSSLE A, STEPHAN K. Analysis of the process characteristics of an absorption heat transformer with compact heat exchangers and the mixture TFE-E181[J]. International Journal of Thermal Sciences, 2000, 39(1):30-38.
[9] 孟凡基, 龙臻, 李华山, 等. TFE-TEGDME-He扩散-吸收式制冷系统实验研究[J]. 低温与超导, 2014,42(6):58-62. (MENG Fanji, LONG Zhen, LI Huashan, et al. Experimental study on a diffusion absorption refrigeration system working with TFE-TEGDME-He[J]. Cryogenics & Superconductivity, 2014,42 (6):58-62. )
[10] 尹铭, 陈嘉宾, 陈沛, 等. 竖直管外降膜吸收传热传质过程强化的研究[J]. 高校化学工程学报, 2002, 16(6):602-608. (YIN Ming, CHEN Jiabin, CHEN Pei, et al. Study on the heat-mass transfer in falling film outside the vertical tube for water vapor absorption into aqueous lithium bromide[J]. Journal of Chemical Engineering of Chinese Universities, 2002, 16(6):602-608. )
[11] 申江, 邹国文, 王建民, 等. 机械振动对吸收式制冷强化作用的理论与试验研究[J]. 流体机械, 2016, 44(3):59-64. (SHEN Jiang, ZOU Guowen, WANG Jianmin, et al. Theoretical and experimental study on the enhancement effect of mechanical vibration on absorption refrigeration[J]. Fluid Machinery, 2016, 44(3):59-64. )
[12] 刘艳丽, 徐士鸣, 韩巍, 等. 摇摆状态下TFE/NMP降膜吸收试验研究[J]. 大连理工大学学报, 2004, 44(1):65-69. (LIU Yanli, XU Shiming, HAN Wei, et al. Experimental study of falling film absorption in a swaying tube using TFE/NMP as working fluid[J]. Journal of Dalian University of Technology, 2004, 44(1):65-69. )
[13] 刘艳丽, 徐士鸣, 张利嵩. 垂直管内TFE/NMP降膜吸收过程中热质传递试验研究[J]. 低温工程, 2002, 23(1):11-18. (LIU Yanli, XU Shiming, ZHANG Lisong. Experimental investigation on heat and mass transfer of falling film absorption in a vertical tube with TFE/NMP solution[J]. Gryogenics, 2002, 23(1):11-18. )
[14] 刘艳丽, 徐士鸣. 摇摆状态下TFE/NMP降膜吸收理论研究[J]. 制冷学报, 2004, 25(3):9-14. (LIU Yanli, XU Shiming. Theoretical study on falling film absorption inside swaying tube with TFE/NMP solution[J]. Journal of Refrigeration, 2004, 25(3): 9-14. )
[15] SISOEV G M, MATAR O K, LAWRENCE C J. Absorption of gas into a wavy falling film[J]. Chemical Engineering Science, 2005, 60(3):827-838.
[16] TSAI B B, PEREZ-BLANCO H. Limits of mass transfer enhancement in lithium bromide-water absorbers by active techniques[J]. International Journal of Heat and Mass Transfer, 1998, 41(15):2409-2416.
[17] KILLION J D, GARIMELLA S. A critical review of models of coupled heat and mass transfer in falling-film absorption[J]. International Journal of Refrigeration, 2001, 24(8):755-797.
[2] 张莉, 徐士鸣. TFE-H2O-TEGDME三元工质热物性参数表达式[J]. 大连理工大学学报, 2005, 45(4): 531-536. (ZHANG Li, XU Shiming, Representations of thermodynamic property of ternary working fluid TFE-H2O-TEGDME[J]. Journal of Dalian University of Technology, 2005, 45(4): 531-536. )
[3] XU Shiming, LIU Yanli, ZHANG Li. Performance research of self regenerated absorption heat transformer cycle using TFE-NMP as working fluids[J]. International Journal of Refrigeration, 2001, 24(6): 510-518.
[4] BAEHR H D, KLOBASA F, SCHARF R. Vapor pressure and liquid and gas densities of 2,2,2-trifluoroethanol[J]. International Journal of Thermophysics, 1989, 10(3):577-589.
[5] 丁帆. 摇摆条件下吸收式制冷机性能的实验研究[D]. 大连:大连海事大学, 2014. (DING Fan. Experimental research on performance of absorption chillers in the case of swing movement[D]. Dalian: Dalian Maritime University, 2014. )
[6] 张天骄. 摇摆对TFE/TEGDME吸收式制冷性能影响的实验研究[D]. 大连:大连海事大学, 2016. (ZHANG Tianjiao. Experiment study on TFE/TEGDME absorption refrigeration performance under swing conditions[D]. Dalian: Dalian Maritime University, 2016. )
[7] STEPHAN K, HENGERER R. Heat transformation with the ternary working fluid TFE-H2O-E181[J]. International Journal of Refrigeration, 1993, 16(2):120-128.
[8] GENSSLE A, STEPHAN K. Analysis of the process characteristics of an absorption heat transformer with compact heat exchangers and the mixture TFE-E181[J]. International Journal of Thermal Sciences, 2000, 39(1):30-38.
[9] 孟凡基, 龙臻, 李华山, 等. TFE-TEGDME-He扩散-吸收式制冷系统实验研究[J]. 低温与超导, 2014,42(6):58-62. (MENG Fanji, LONG Zhen, LI Huashan, et al. Experimental study on a diffusion absorption refrigeration system working with TFE-TEGDME-He[J]. Cryogenics & Superconductivity, 2014,42 (6):58-62. )
[10] 尹铭, 陈嘉宾, 陈沛, 等. 竖直管外降膜吸收传热传质过程强化的研究[J]. 高校化学工程学报, 2002, 16(6):602-608. (YIN Ming, CHEN Jiabin, CHEN Pei, et al. Study on the heat-mass transfer in falling film outside the vertical tube for water vapor absorption into aqueous lithium bromide[J]. Journal of Chemical Engineering of Chinese Universities, 2002, 16(6):602-608. )
[11] 申江, 邹国文, 王建民, 等. 机械振动对吸收式制冷强化作用的理论与试验研究[J]. 流体机械, 2016, 44(3):59-64. (SHEN Jiang, ZOU Guowen, WANG Jianmin, et al. Theoretical and experimental study on the enhancement effect of mechanical vibration on absorption refrigeration[J]. Fluid Machinery, 2016, 44(3):59-64. )
[12] 刘艳丽, 徐士鸣, 韩巍, 等. 摇摆状态下TFE/NMP降膜吸收试验研究[J]. 大连理工大学学报, 2004, 44(1):65-69. (LIU Yanli, XU Shiming, HAN Wei, et al. Experimental study of falling film absorption in a swaying tube using TFE/NMP as working fluid[J]. Journal of Dalian University of Technology, 2004, 44(1):65-69. )
[13] 刘艳丽, 徐士鸣, 张利嵩. 垂直管内TFE/NMP降膜吸收过程中热质传递试验研究[J]. 低温工程, 2002, 23(1):11-18. (LIU Yanli, XU Shiming, ZHANG Lisong. Experimental investigation on heat and mass transfer of falling film absorption in a vertical tube with TFE/NMP solution[J]. Gryogenics, 2002, 23(1):11-18. )
[14] 刘艳丽, 徐士鸣. 摇摆状态下TFE/NMP降膜吸收理论研究[J]. 制冷学报, 2004, 25(3):9-14. (LIU Yanli, XU Shiming. Theoretical study on falling film absorption inside swaying tube with TFE/NMP solution[J]. Journal of Refrigeration, 2004, 25(3): 9-14. )
[15] SISOEV G M, MATAR O K, LAWRENCE C J. Absorption of gas into a wavy falling film[J]. Chemical Engineering Science, 2005, 60(3):827-838.
[16] TSAI B B, PEREZ-BLANCO H. Limits of mass transfer enhancement in lithium bromide-water absorbers by active techniques[J]. International Journal of Heat and Mass Transfer, 1998, 41(15):2409-2416.
[17] KILLION J D, GARIMELLA S. A critical review of models of coupled heat and mass transfer in falling-film absorption[J]. International Journal of Refrigeration, 2001, 24(8):755-797.