石蜡基纳米金属复合相变材料热性能的实验研究
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摘要
以石蜡为复合相变材料的基体,分别添加氧化铜、二氧化硅和氧化锌的纳米颗粒通过两步法制备多种石蜡基纳米金属复合相变材料。通过改变所添加纳米金属颗粒种类、质量分数和颗粒粒径,对比分析实验模型内复合相变材料蓄放热过程的温度曲线,来探究以上参数对复合相变材料热性能的影响。结果表明,通过添加纳米金属颗粒的方式能够有效提升石蜡的蓄放热性能,添加氧化铜颗粒的效果要优于氧化锌颗粒和二氧化硅颗粒;复合相变材料的导热系数和动力黏度均随颗粒浓度的增加而增大,两者共同决定着复合相变材料的换热过程能否被强化;纳米金属颗粒的粒径越小,越有利于增强对复合相变材料的热性能,添加30 nm粒径纳米颗粒相对于100 nm粒径纳米颗粒蓄热速率能提升26%,放热速率能提升41%。
With paraffin as the matrix of the composite PCM, the nanometal-paraffin composite phase change materials(PCMs) were prepared by a two-step process by adding the nanoparticles of copper oxide, silicon dioxide and zinc oxide respectively. The thermal performance factors of composite P CMs were studied by changing the types of nanometal particles, the percentage of addition and the particle size and making a contrastive analysis of the temperature curve of the heat storage and release process of the composite phase change material in the experimental model. The results show that the heat storage and release performance of paraffin wax can be effectively improved by adding nano-metal particles. The effect of adding copper oxide particles is better than that of zinc oxide particles and silica particles. The thermal conductivity and dynamic viscosity of the composite PCM increase with the increase of the particle concentration,which together determine whether the heat transfer process of the composite PCM is strengthened. The smaller the particle size of the nanometal particles, the more favorable it is in enhancing the thermal property of the composite PCM. Adding 30 nm particle size nanometal particles to the composite PCM can increase the heat storage rate by 26% compared with the 100 nm particle size, and the heat release rate can be increased by 41%.
With paraffin as the matrix of the composite PCM, the nanometal-paraffin composite phase change materials(PCMs) were prepared by a two-step process by adding the nanoparticles of copper oxide, silicon dioxide and zinc oxide respectively. The thermal performance factors of composite P CMs were studied by changing the types of nanometal particles, the percentage of addition and the particle size and making a contrastive analysis of the temperature curve of the heat storage and release process of the composite phase change material in the experimental model. The results show that the heat storage and release performance of paraffin wax can be effectively improved by adding nano-metal particles. The effect of adding copper oxide particles is better than that of zinc oxide particles and silica particles. The thermal conductivity and dynamic viscosity of the composite PCM increase with the increase of the particle concentration,which together determine whether the heat transfer process of the composite PCM is strengthened. The smaller the particle size of the nanometal particles, the more favorable it is in enhancing the thermal property of the composite PCM. Adding 30 nm particle size nanometal particles to the composite PCM can increase the heat storage rate by 26% compared with the 100 nm particle size, and the heat release rate can be increased by 41%.
引文
[1]华维三,章学来,罗孝学,等.纳米金属/石蜡复合相变蓄热材料的实验研究[J].太阳能学报,2017,38(6):1723-1728.
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[8] Sharma P,Baek I H,Cho T,et al. Enhancement of thermal conductivity of ethylene glycol based silver nanofluids[J]. Powder Technology,2011,208(1):7-19.
[9] Liu M S,Lin M C C,Huang I T,et al. Enhancement of thermal conductivity with CuO for nanofluids[J]. Chemical engineering&technology,2006,29(1):72-77.
[10] Murshed S,Leong K,Yang C. Enhanced thermal conductivity of TiO2-water based nanofluids[J]. International Journal of Thermal Sciences,2005,44(4):367-373.
[11] Ho C J,Gao J Y. An experimental study on melting heat transfer of paraffin dispersed with Al2O3nanoparticles in a vertical enclosure[J]. Internation?al Journal of Heat and Mass Transfer,2013,62:2-8.
[12] Zeng Y,Fan L W,Xiao Y Q,et al. An experimental investigation of melting of nanoparticle-enhanced phase change materials(NePCMs)in a bot?tom-heated vertical cylindrical cavity[J]. International Journal of Heat and Mass Transfer,2013,66:111-117.
[2] Yang Z,Garimella S V. Melting of phase change materials with volume change in metal foams[J]. Journal of Heat Transfer,2010,132(6):062301.
[3] Krishnan S,Murthy J Y,Garimella S V. A two-temperature model for solid-liquid phase change in metal foams[J]. Journal of heat transfer,2005,127(9):995-1004.
[4]张月莲,郑丹星.石蜡相变材料在同心环隙管内的基本传热行为[J].北京化工大学学报(自然科学版),2006(2):5-8,12.
[5] Erek A,Ilken Z,Acar M. A. Experimental and numerical investigation of thermal energy storage with a finned tube[J]. International journal of energy research,2005,29(4):283-301.
[6]凌空,封永亮,陶文铨.带环状翅片管式相变储热器的数值模拟[J].工程热物理学报,2012,33(8):1407-1410.
[7] Hong K,Hong T K,Yang H S. Thermal conductivity of Fe nanofluids depending on the cluster size of nanoparticles[J]. Applied Physics Letters,2006,88(3):031901.
[8] Sharma P,Baek I H,Cho T,et al. Enhancement of thermal conductivity of ethylene glycol based silver nanofluids[J]. Powder Technology,2011,208(1):7-19.
[9] Liu M S,Lin M C C,Huang I T,et al. Enhancement of thermal conductivity with CuO for nanofluids[J]. Chemical engineering&technology,2006,29(1):72-77.
[10] Murshed S,Leong K,Yang C. Enhanced thermal conductivity of TiO2-water based nanofluids[J]. International Journal of Thermal Sciences,2005,44(4):367-373.
[11] Ho C J,Gao J Y. An experimental study on melting heat transfer of paraffin dispersed with Al2O3nanoparticles in a vertical enclosure[J]. Internation?al Journal of Heat and Mass Transfer,2013,62:2-8.
[12] Zeng Y,Fan L W,Xiao Y Q,et al. An experimental investigation of melting of nanoparticle-enhanced phase change materials(NePCMs)in a bot?tom-heated vertical cylindrical cavity[J]. International Journal of Heat and Mass Transfer,2013,66:111-117.
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