超声强化小型溴化锂吸收式制冷机性能实验研究
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摘要
在10kW溴化锂吸收式制冷机发生器侧壁(厚度4mm)粘贴超声波振子,实验研究了频率为28kHz超声波在溴化锂溶液两种不同液位高度下对机组性能的影响,并对超声波强化溴化锂溶液沸腾传热传质机理进行了分析。实验结果表明:无超声波作用时,溶液泵转速控制电机运行频率从17Hz升高到18Hz,溶液泵流量升高,发生器中溴化锂溶液液位升高5cm,制冷量增加16.8%,但性能系数(COP)降低44.3%;而施加超声波作用可以强化溴化锂吸收式制冷机性能,且强化效果与溶液液位有关,当机组发生器内液位高于超声波换能器中心线8～10cm时,机组制冷量升高19.6%,COP提高13.8%;而当液位与换能器中心线相差3～5cm时,制冷量提升并不明显,仅为4.7%,COP提升5.4%。实验结果为超声波作用提升小型太阳能溴化锂吸收式制冷系统性能提供指导和依据。
With ultrasonic transducers stuck on the side walls(4 mm-thick) of a generator, the effects of ultrasonic waves(28 kHz) on the performance of an absorption refrigerator(10 kW) were experimentally investigated under two height levels of LiBr solution in the generator. The mechanism of boiling heat and mass transfer enhanced by ultrasonic waves in LiBr solution was also analyzed. For the case without ultrasonic waves, the flow rate of LiBr solution increases with the speed-motor frequency of solution pump increasing from 17 Hz to 18 Hz, the height level of the solution in the generator rises by 5 cm and the refrigeration capacity increases by 16.8%, but the COP(coefficient of performance) decreases by 44.3%.The ultrasonic waves enhance the refrigerator performance and the effects are related to the solution height levels in the generator. The refrigeration capacity and COP are improved by 19.6% and 13.8%,respectively when the solution height level is 8—10 cm higher than the center line of the ultrasonic transducers; when the solution height level is 3—5 cm higher, the refrigeration capacity and COP are only improved by 4.7% and 5.4%, respectively. The experimental results provide guidelines for performance improvement of small LiBr absorption refrigerators by using ultrasonic waves.
With ultrasonic transducers stuck on the side walls(4 mm-thick) of a generator, the effects of ultrasonic waves(28 kHz) on the performance of an absorption refrigerator(10 kW) were experimentally investigated under two height levels of LiBr solution in the generator. The mechanism of boiling heat and mass transfer enhanced by ultrasonic waves in LiBr solution was also analyzed. For the case without ultrasonic waves, the flow rate of LiBr solution increases with the speed-motor frequency of solution pump increasing from 17 Hz to 18 Hz, the height level of the solution in the generator rises by 5 cm and the refrigeration capacity increases by 16.8%, but the COP(coefficient of performance) decreases by 44.3%.The ultrasonic waves enhance the refrigerator performance and the effects are related to the solution height levels in the generator. The refrigeration capacity and COP are improved by 19.6% and 13.8%,respectively when the solution height level is 8—10 cm higher than the center line of the ultrasonic transducers; when the solution height level is 3—5 cm higher, the refrigeration capacity and COP are only improved by 4.7% and 5.4%, respectively. The experimental results provide guidelines for performance improvement of small LiBr absorption refrigerators by using ultrasonic waves.
引文
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[16]张艾萍,冯卓,丁权,等.超声空化对污垢沉积特性影响的数值研究[J].化工学报,2017,68(s1):184-190.ZHANG A P,FENG Z,DING Q,et al.Simulation study on influential of ultrasonic cavitation on fouling deposition characteristic[J].CIESCJournal,2017,68(s1):184-190.
[17]OH Y K,PARK S H,CHO Y I.A study of the effect of ultrasonic vibrations on phase-change heat transfer[J].International Journal of Heat and Mass Transfer,2002,45(23):4631-4641.
[18]BARTOLI C,BAFFIGI F.Effects of ultrasonic waves on the heat transfer enhancement in subcooled boiling[J].Experimental Thermal and Fluid Science,2011,35(3):423-432.
[19]BAFFIGI F,BARTOLI C.Influence of the ultrasounds on the heat transfer in single phase free convection and in saturated pool boiling[J].Experimental Thermal and Fluid Science,2012,36(1):12-21.
[20]KIM H Y,KIM Y G,KANG B H.Enhancement of natural convection and pool boiling heat transfer via ultrasonic vibration[J].International Journal of Heat and Mass Transfer,2004,47:2831-2840.
[21]WONG S W,CHON W Y.Effects of ultrasonic vibrations on heat transfer to liquids by natural convection and by boiling[J].AIChEJournal,1969,15(2):281-288.
[22]HYUN S,LEE D R,LOH B G.Investigation of convective heat transfer augmentation using acoustic streaming generated by ultrasonic vibrations[J].International Journal of Heat and Mass Transfer,2005,48(3):703-718.
[23]CAI J,HUAI X,YAN R,et al.Numerical simulation on enhancement of natural convection heat transfer by acoustic cavitation in a square enclosure[J].Applied Thermal Engineering,2009,29(10):1973-1982.
[24]YAO Y,ZHANG W J,YANG K,et al.Theoretical model on the heat and mass transfer in silica gel packed beds duringthe regeneration assisted by high-intensity ultrasound[J].International Journal of Heat and Mass Transfer,2012,55(23):7133-7143.
[25]YAO Y,ZHANG W J,HE B.Investigation on the kinetic models for the regeneration of silica gel by hot air combined with power ultrasonic[J].Energy Conversion and Management,2011,52(11):3319-3326.
[26]刘丽英,丁忠伟,常李静,等.超声波技术强化膜分离过程的研究进展[J].化工进展,2008,27(1):32-37.LIU L Y,DING Z W,CHANG L J,et al.Progress in membrane separation enhanced by ultrasound[J].Chemical Industry and Engineering Progress,2008,27(1):32-37.
[27]吴莉莉,李昕,赵之平.超声波强化膜蒸馏研究进展[J].化工进展,2009,28(s1):38-40.WU L L,LI X,ZHAO Z P.Research progress of ultrasonic enhanced membrane distillation[J].Chemical Industry and Engineering Progress,2009,28(s1):38-40.
[28]HAN X D,ZHANG S W,TANG Y,et al.Mass transfer enhancement for LiBr solution using ultrasonic wave[J].Journal of Central South University,2016,23(2):405-412.
[29]汤勇,韩晓东,陈川,等.超声波对吸收式制冷强化传质的影响[J].华南理工大学学报(自然科学版),2012,40(10):115-120.TANG Y,HAN X D,CHEN C,et al.Effects of ultrasonic waves on mass transfer enhancement in absorption refrigeration system[J].Journal of South China University of Technology(Natural Science Edition),2012,40(10):115-120.
[30]王岗,全贞花,赵耀华,等.太阳能-热泵复合供能系统[J].化工学报,2017,68(5):2132-2139.WANG G,QUAN Z H,ZHAO Y H,et al.Solar-heat pump combined energy system[J].CIESC Journal,2017,68(5):2132-2139.
[31]何梓年,朱宁,刘芳,等.太阳能吸收式空调及供热系统的设计和性能[J].太阳能学报,2001,22(1):6-11.HE Z N,ZHU N,LIU F,et al.Design and performance of a solar absorption air-conditioning and heat-supply system[J].Acta Energiae Solaris Sinica,2001,22(1):6-11.
[32]HAMMAD M A,AUDI M S.Performance of a solar LiBr-water absorption refrigeration system[J].Renewable Energy,1992,2(3):257-282.
[33]ROSIEK S,BATLLES F J.Integration of the solar thermal energy in the construction:Analysis of the solar-assisted air-conditioning system installed in CIESOL building[J].Renewable Energy,2009,34(6):1423-1431.
[34]孙宝芝,姜任秋,淮秀兰,等.声空化及其强化传热技术研究进展[J].哈尔滨工程大学学报,2004,25(1):19-24.SUN B Z,JIANG R Q,HUAI X L,et al.Development of the research on acoustic cavitation enhancement of heat transfer[J].Journal of Harbin Engineering University,2004,25(1):19-24.
[35]LEGAY M,GONDREXON N,PERSON S L,et al.Enhancement of heat transfer by ultrasound:review and recent advances[J].International Journal of Chemical Engineering,2011(2):1-17.
[36]ZHENG M J,LI B,WAN Z P,et al.Ultrasonic heat transfer enhancement on different structural tubes in LiBr solution[J].Applied Thermal Engineering,2016,106:625-633.
[37]赵之平,陈澄华.超声传质过程机理[J].化工设计,1997(6):32-35.ZHAO Z P,CHEN C H.Mass transfer processes by using ultrasonic[J].Chemical Engineering Design,1997(6):32-35.
[38]韩晓东.太阳能吸收式制冷系统及其热质传递强化研究[D].广州:华南理工大学,2016.HAN X D.Study on solar absorption refrigeration system and its heat and mass transfer enhancement[D].Guangzhou:South China University of Technology,2016.
[2]ULLAH K R,SAIDUR R,PING H W,et al.A review of solar thermal refrigeration and cooling methods[J].Renewable and Sustainable Energy Reviews,2013,24(10):499-513.
[3]GOMRI R,HAKIMI R.Second law analysis of double effect vapour absorption cooler system[J].Energy Conversion and Management,2008,49(11):3343-3348.
[4]MODI B,MUDGAL A,PATEL B.Energy and exergy investigation of small capacity single effect lithium bromide absorption refrigeration system[J].Energy Procedia,2017,109:203-210.
[5]GU Y X,WU Y Y,KE X.Experimental research on a new solar pumpfree lithium bromide absorption refrigeration system with a second generator[J].Solar Energy,2008,82(1):33-42.
[6]梁之琦,徐孟飞,殷勇高.LiCl溶液垂直管外降膜发生效果的实验[J].化工学报,2016,67(s2):87-93.LAING Z Q,XU M F,YIN Y G.Effect of falling-film generation outside vertical tube with lithium chloride aqueous solution[J].CIESCJournal,2016,67(s2):87-93.
[7]陈达卫,王启杰,林毅强.高效传热管的实验研究[J].化工学报,2004,55(6):888-895.CHEN D W,WANG Q J,LIN Y Q.Enhanced heat transfer tubes[J].Journal Chemical Industry and Engineering(China),2004,55(6):888-895.
[8]陈亚平,施晨洁,施明恒.双面膜反转强化吸收过程传热传质[J].化工学报,2008,59(1):19-24.CHEN Y P,SHI C J,SHI M H.Heat and mass transfer enhancement during absorption process with double-side film-inverting configuration[J].Journal Chemical Industry and Engineering(China),2008,59(1):19-24.
[9]GLEBOV D,SETTERWALL F.Experimental study of heat transfer additive influence on the absorption chiller performance[J].International Journal of Refrigeration,2002,25(5):538-545.
[10]解国珍,王亮亮.纳米微粒及其分散剂对溴化锂溶液表面张力和沸腾温度的影响[J].化工学报,2014,65(11):4315-4320.XIE G Z,WANG L L.Effect of nano-particles and relevant dispersants on surface tension and boiling temperature of LiBr aqueous solution[J].CIESC Journal,2014,65(11):4315-4320.
[11]陈光明,何一坚,章文斌.溴化锂溶液空气预冷却绝热吸收过程研究[J].太阳能学报,2002,23(3):344-348.CHEN G M,HE Y J,ZHANG W B.Sdudy on lithium-bromide aqueous solution air-precooled adiabatic absorption process[J].Acta Energiae Solaris Sinica,2002,23(3):344-348.
[12]韩东,阮建平,梁林.传热传质分离式太阳能吸收式制冷机实验研究[J].太阳能学报,2009,30(9):1168-1172.HAN D,RUAN J P,LIANG L.Experiment study on solar powered lithium bromide absorption chiller with heat and mass separated[J].Acta Energiae Solaris Sinica,2009,30(9):1168-1172.
[13]王萍辉.超声空化影响因素[J].河北理工学院学报,2003,25(4):154-161.WANG P H.A study and analysis on influencing factor of the ultrasonic cavitation[J].Journal of Hebei Institute of Technology,2003,25(4):154-161.
[14]刘雪粉,俞云良,陆向红,等.超声波应用于吸附/脱附过程的研究进展[J].化工进展,2006,25(6):639-645.LIU X F,YU Y L,LU X H,et al.Research progress of ultrasound application to adsorption/desorption process[J].Chemical Industry and Engineering Progress,2006,25(6):639-645.
[15]姚晔.超声波技术在空调除湿剂强化再生中的应用研究进展[J].制冷学报,2012,33(6):12-18.YAO Y.Research progress in the application of ultrasonic technology in the regeneration of desiccants for air-conditioning[J].Journal of Refrigeration,2012,33(6):12-18.
[16]张艾萍,冯卓,丁权,等.超声空化对污垢沉积特性影响的数值研究[J].化工学报,2017,68(s1):184-190.ZHANG A P,FENG Z,DING Q,et al.Simulation study on influential of ultrasonic cavitation on fouling deposition characteristic[J].CIESCJournal,2017,68(s1):184-190.
[17]OH Y K,PARK S H,CHO Y I.A study of the effect of ultrasonic vibrations on phase-change heat transfer[J].International Journal of Heat and Mass Transfer,2002,45(23):4631-4641.
[18]BARTOLI C,BAFFIGI F.Effects of ultrasonic waves on the heat transfer enhancement in subcooled boiling[J].Experimental Thermal and Fluid Science,2011,35(3):423-432.
[19]BAFFIGI F,BARTOLI C.Influence of the ultrasounds on the heat transfer in single phase free convection and in saturated pool boiling[J].Experimental Thermal and Fluid Science,2012,36(1):12-21.
[20]KIM H Y,KIM Y G,KANG B H.Enhancement of natural convection and pool boiling heat transfer via ultrasonic vibration[J].International Journal of Heat and Mass Transfer,2004,47:2831-2840.
[21]WONG S W,CHON W Y.Effects of ultrasonic vibrations on heat transfer to liquids by natural convection and by boiling[J].AIChEJournal,1969,15(2):281-288.
[22]HYUN S,LEE D R,LOH B G.Investigation of convective heat transfer augmentation using acoustic streaming generated by ultrasonic vibrations[J].International Journal of Heat and Mass Transfer,2005,48(3):703-718.
[23]CAI J,HUAI X,YAN R,et al.Numerical simulation on enhancement of natural convection heat transfer by acoustic cavitation in a square enclosure[J].Applied Thermal Engineering,2009,29(10):1973-1982.
[24]YAO Y,ZHANG W J,YANG K,et al.Theoretical model on the heat and mass transfer in silica gel packed beds duringthe regeneration assisted by high-intensity ultrasound[J].International Journal of Heat and Mass Transfer,2012,55(23):7133-7143.
[25]YAO Y,ZHANG W J,HE B.Investigation on the kinetic models for the regeneration of silica gel by hot air combined with power ultrasonic[J].Energy Conversion and Management,2011,52(11):3319-3326.
[26]刘丽英,丁忠伟,常李静,等.超声波技术强化膜分离过程的研究进展[J].化工进展,2008,27(1):32-37.LIU L Y,DING Z W,CHANG L J,et al.Progress in membrane separation enhanced by ultrasound[J].Chemical Industry and Engineering Progress,2008,27(1):32-37.
[27]吴莉莉,李昕,赵之平.超声波强化膜蒸馏研究进展[J].化工进展,2009,28(s1):38-40.WU L L,LI X,ZHAO Z P.Research progress of ultrasonic enhanced membrane distillation[J].Chemical Industry and Engineering Progress,2009,28(s1):38-40.
[28]HAN X D,ZHANG S W,TANG Y,et al.Mass transfer enhancement for LiBr solution using ultrasonic wave[J].Journal of Central South University,2016,23(2):405-412.
[29]汤勇,韩晓东,陈川,等.超声波对吸收式制冷强化传质的影响[J].华南理工大学学报(自然科学版),2012,40(10):115-120.TANG Y,HAN X D,CHEN C,et al.Effects of ultrasonic waves on mass transfer enhancement in absorption refrigeration system[J].Journal of South China University of Technology(Natural Science Edition),2012,40(10):115-120.
[30]王岗,全贞花,赵耀华,等.太阳能-热泵复合供能系统[J].化工学报,2017,68(5):2132-2139.WANG G,QUAN Z H,ZHAO Y H,et al.Solar-heat pump combined energy system[J].CIESC Journal,2017,68(5):2132-2139.
[31]何梓年,朱宁,刘芳,等.太阳能吸收式空调及供热系统的设计和性能[J].太阳能学报,2001,22(1):6-11.HE Z N,ZHU N,LIU F,et al.Design and performance of a solar absorption air-conditioning and heat-supply system[J].Acta Energiae Solaris Sinica,2001,22(1):6-11.
[32]HAMMAD M A,AUDI M S.Performance of a solar LiBr-water absorption refrigeration system[J].Renewable Energy,1992,2(3):257-282.
[33]ROSIEK S,BATLLES F J.Integration of the solar thermal energy in the construction:Analysis of the solar-assisted air-conditioning system installed in CIESOL building[J].Renewable Energy,2009,34(6):1423-1431.
[34]孙宝芝,姜任秋,淮秀兰,等.声空化及其强化传热技术研究进展[J].哈尔滨工程大学学报,2004,25(1):19-24.SUN B Z,JIANG R Q,HUAI X L,et al.Development of the research on acoustic cavitation enhancement of heat transfer[J].Journal of Harbin Engineering University,2004,25(1):19-24.
[35]LEGAY M,GONDREXON N,PERSON S L,et al.Enhancement of heat transfer by ultrasound:review and recent advances[J].International Journal of Chemical Engineering,2011(2):1-17.
[36]ZHENG M J,LI B,WAN Z P,et al.Ultrasonic heat transfer enhancement on different structural tubes in LiBr solution[J].Applied Thermal Engineering,2016,106:625-633.
[37]赵之平,陈澄华.超声传质过程机理[J].化工设计,1997(6):32-35.ZHAO Z P,CHEN C H.Mass transfer processes by using ultrasonic[J].Chemical Engineering Design,1997(6):32-35.
[38]韩晓东.太阳能吸收式制冷系统及其热质传递强化研究[D].广州:华南理工大学,2016.HAN X D.Study on solar absorption refrigeration system and its heat and mass transfer enhancement[D].Guangzhou:South China University of Technology,2016.