正压下酒精水混合蒸气在板式换热器凝结时的压降研究
|
摘要
为研究不同浓度酒精水混合蒸气流经板式换热器时压降的变化,在实验压力为110 kPa时,在板式换热器中进行了酒精和水混合蒸气凝结换热实验,酒精的气相质量浓度分别为0、1%、2%、5%、10%和20%,蒸气的质量流量为6～12 kg/h,在实验中测量了板式换热器进出口的压降,并进行了可视化观察。结果表明:各浓度的混合蒸气压降都随流量的增大而增大,压降与出口蒸气干度几乎呈线性关系,摩擦因子随出口干度增大而呈指数形式的递减;当流量不变时,压降随浓度的增大而增大,浓度越大流量越小,所对应的摩擦因子也越小;纯水蒸汽凝结时依然呈现出膜状凝结,而混合蒸气由于凝结时存在Marangoni效应,出现了非膜状凝结的形态;对实验数据以等效Re和Bo为自变量,以摩擦因子为因变量进行了拟合,拟合公式的平均误差为24.5%。
To investigate pressure drop(PD) change when ethanol-water mixed vapor condense in a vertical plate heat exchanger(PHE),a series of experiments were carried out in the present study.The experimental system pressure was 110 kPa,the ethanol gas phase concentration was 0,1%,2%,5%,10% and 20%,respectively,and vapor mass flux was varied from 6 to 12 kg/h.The PD was recorded and visual observation was made during condensation of mixed vapor.The experimental result showed that the PD increases with mass flux for every concentration.The PD increases almost linearly with the outlet vapor quality,while friction factor decreases exponentially with the outlet vapor quality.The PD increases with condensation; the higher concentration and the lower mass flux,the smaller the associated PD.Filmwise condensation appears for pure water vapor condensation,and non-filmwise condensation mode emerges for the mixed vapor due to the Marangoni effect.Finally,results for the friction factor are correlated against the Boiling number and equivalent Reynolds number of the two-phase condensing flow.The correlation equations can well represent the experimental data with average deviations of 24.5% for friction factor.
To investigate pressure drop(PD) change when ethanol-water mixed vapor condense in a vertical plate heat exchanger(PHE),a series of experiments were carried out in the present study.The experimental system pressure was 110 kPa,the ethanol gas phase concentration was 0,1%,2%,5%,10% and 20%,respectively,and vapor mass flux was varied from 6 to 12 kg/h.The PD was recorded and visual observation was made during condensation of mixed vapor.The experimental result showed that the PD increases with mass flux for every concentration.The PD increases almost linearly with the outlet vapor quality,while friction factor decreases exponentially with the outlet vapor quality.The PD increases with condensation; the higher concentration and the lower mass flux,the smaller the associated PD.Filmwise condensation appears for pure water vapor condensation,and non-filmwise condensation mode emerges for the mixed vapor due to the Marangoni effect.Finally,results for the friction factor are correlated against the Boiling number and equivalent Reynolds number of the two-phase condensing flow.The correlation equations can well represent the experimental data with average deviations of 24.5% for friction factor.
引文
[1] 栾辉宝,陈斌,郑伟业,等.板壳式换热器传热与流动特性研究[J].热能动力工程,2014,29(5):503-508.LUAN Hui-bao,CHEN Bin,ZHENG Wei-ye,et al.Study of the heat transfer and flow characteristics of a plate and shell heat exchanger[J].Journal of Engineering for Thermal Energy & Power,2014,29(5):503-508.
[2] 孙斌,张冠男,左瑞良.板式换热器内Cu-水纳米流体流动和传热特性数值模拟[J].热能动力工程,2015,30(5):666-671.SUN Bin,ZHANG Guan-nan,ZUO Rui-liang.Numerical simulation of the flow and heat transfer characteristics of a cu-water nano-fluid inside a plate type heat exchanger[J].Journal of Engineering for Thermal Energy & Power,2015,30(5):666-671.
[3] WANG Z,ZHAO Z.Analysis of performance of steam condensation heat transfer and pressure drop in plate condensers[J].Heat Transfer Eng,1993,14(4):32-41.
[4] JOKAR A,HOSNI M H,ECKELS S J.Dimensional analysis on the evaporation and condensation of refrigerant R-134a in minichannels plate heat exchangers[J].Applied Thermal Engineering,2006,25:2287-2300.
[5] LONGO G A,GASPARELLA A.Heat transfer and pressure drop during HFC-134a condensation inside a commercial brazed plate heat exchanger[C]//International Congress of Refrigeration,Beijing,2007.
[6] HAO P,XIANG L.Neural networks analysis of thermal characteristics on plate-fin heat exchangers with limited experimental data[J].Applied Thermal Engineering,2009,29(11):2251-2256.
[7] NILPUENG K ,WONGWISES S.Two-phase gas-liquid flow characteristics inside a plate heat exchanger[J].Experimental Thermal and Fluid Science,2010,34(8):1217-1229.
[8] TABOAS F,VALLES M,BOUROUIS M,CORONAS A.Assessment of boiling heat transfer and pressure drop correlations of ammonia/water mixture in a plate heat exchanger[J].International Journal of Refrigeration,2012,35(3):633-644.
[9] GIOVANNI A L,ZILIO C.Condensation of the low GWP refrigerant HFC1234yf inside a brazed plate heat exchanger[J].International Journal of Refrigeration,2013,36(2):612-621.
[10] LONGO G A,ZILIO C,RIGHETTI G,et al.Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger[J].International Journal of Refrigeration,2014,38(1):250-259.
[11] 乔宏斌,王顺,胡申华.水-酒精混合蒸气在板式换热器中凝结时的压降特性[J].动力工程学报,2017,37(1):33-38.QIAO Hong-bin,WANG Shun,HU Shen-hua.The characteristics of pressure drop in plate heat exchanger for ethanol-water vapor mixtures condensation [J].Journal of Chinese Society of Power Engineering,2017,37(1):33-38.
[12] 胡申华,彭建军,高策.板式换热器中水酒精混合蒸气凝结换热特性的实验研究[J].中国电机工程学报,2017,37(5):1441-1447.HU Shen-hua,PENG Jian-jun,GAO Ce.Experimental investigations on water-ethanol mixed vapor condensation heat transfer in plate heat exchanger[J].Proc Chin Soc Elect Eng,2017,37(5):1441-1447.
[13] HU Shen-hua,MA Xiang-rong,ZHOU Wei-qing.Condensation heat transfer of ethanol-water vapor in a plate heat exchanger[J].Applied Thermal Engineering,2017,113(2):1047-1055.
[14] EUNGCHAN L,HOON K,YONGCHAN K.Flow boiling heat transfer and pressure drop of water in a plate heat exchanger with corrugated channels at low mass flux conditions[J].International Journal of Heat and Mass Transfer ,2014,77(4):37-45.
[15] KLINE S J,MCCLINTOCK F A.Describing uncertainties in single-sample experiments[J].Mech Eng,1953,75(1):3-12.
[16] FUJII T.Theory of laminar film condensation[M].New York:Springer-Verlag,1991.
[17] 蒋维钧,雷良恒,刘茂林,等.化工原理[M].北京:清华大学出版社,2003.JIANG Wei-jun,LEI Liang-heng,LIU Mao-lin,et al.Chemical principle [M].Beijing:Tsinghua University Press,2003.
[18] KUO W S,LIE Y M,HSIEH Y Y,et al.Condensation heat transfer and pressure drop of refrigerant R-410A flow in a vertical plate heat exchanger[J].International Journal of Heat and Mass Transfer ,2005,48(25/26):5205-5220.
[2] 孙斌,张冠男,左瑞良.板式换热器内Cu-水纳米流体流动和传热特性数值模拟[J].热能动力工程,2015,30(5):666-671.SUN Bin,ZHANG Guan-nan,ZUO Rui-liang.Numerical simulation of the flow and heat transfer characteristics of a cu-water nano-fluid inside a plate type heat exchanger[J].Journal of Engineering for Thermal Energy & Power,2015,30(5):666-671.
[3] WANG Z,ZHAO Z.Analysis of performance of steam condensation heat transfer and pressure drop in plate condensers[J].Heat Transfer Eng,1993,14(4):32-41.
[4] JOKAR A,HOSNI M H,ECKELS S J.Dimensional analysis on the evaporation and condensation of refrigerant R-134a in minichannels plate heat exchangers[J].Applied Thermal Engineering,2006,25:2287-2300.
[5] LONGO G A,GASPARELLA A.Heat transfer and pressure drop during HFC-134a condensation inside a commercial brazed plate heat exchanger[C]//International Congress of Refrigeration,Beijing,2007.
[6] HAO P,XIANG L.Neural networks analysis of thermal characteristics on plate-fin heat exchangers with limited experimental data[J].Applied Thermal Engineering,2009,29(11):2251-2256.
[7] NILPUENG K ,WONGWISES S.Two-phase gas-liquid flow characteristics inside a plate heat exchanger[J].Experimental Thermal and Fluid Science,2010,34(8):1217-1229.
[8] TABOAS F,VALLES M,BOUROUIS M,CORONAS A.Assessment of boiling heat transfer and pressure drop correlations of ammonia/water mixture in a plate heat exchanger[J].International Journal of Refrigeration,2012,35(3):633-644.
[9] GIOVANNI A L,ZILIO C.Condensation of the low GWP refrigerant HFC1234yf inside a brazed plate heat exchanger[J].International Journal of Refrigeration,2013,36(2):612-621.
[10] LONGO G A,ZILIO C,RIGHETTI G,et al.Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger[J].International Journal of Refrigeration,2014,38(1):250-259.
[11] 乔宏斌,王顺,胡申华.水-酒精混合蒸气在板式换热器中凝结时的压降特性[J].动力工程学报,2017,37(1):33-38.QIAO Hong-bin,WANG Shun,HU Shen-hua.The characteristics of pressure drop in plate heat exchanger for ethanol-water vapor mixtures condensation [J].Journal of Chinese Society of Power Engineering,2017,37(1):33-38.
[12] 胡申华,彭建军,高策.板式换热器中水酒精混合蒸气凝结换热特性的实验研究[J].中国电机工程学报,2017,37(5):1441-1447.HU Shen-hua,PENG Jian-jun,GAO Ce.Experimental investigations on water-ethanol mixed vapor condensation heat transfer in plate heat exchanger[J].Proc Chin Soc Elect Eng,2017,37(5):1441-1447.
[13] HU Shen-hua,MA Xiang-rong,ZHOU Wei-qing.Condensation heat transfer of ethanol-water vapor in a plate heat exchanger[J].Applied Thermal Engineering,2017,113(2):1047-1055.
[14] EUNGCHAN L,HOON K,YONGCHAN K.Flow boiling heat transfer and pressure drop of water in a plate heat exchanger with corrugated channels at low mass flux conditions[J].International Journal of Heat and Mass Transfer ,2014,77(4):37-45.
[15] KLINE S J,MCCLINTOCK F A.Describing uncertainties in single-sample experiments[J].Mech Eng,1953,75(1):3-12.
[16] FUJII T.Theory of laminar film condensation[M].New York:Springer-Verlag,1991.
[17] 蒋维钧,雷良恒,刘茂林,等.化工原理[M].北京:清华大学出版社,2003.JIANG Wei-jun,LEI Liang-heng,LIU Mao-lin,et al.Chemical principle [M].Beijing:Tsinghua University Press,2003.
[18] KUO W S,LIE Y M,HSIEH Y Y,et al.Condensation heat transfer and pressure drop of refrigerant R-410A flow in a vertical plate heat exchanger[J].International Journal of Heat and Mass Transfer ,2005,48(25/26):5205-5220.