摘要
为研究纳米熔盐传热储热性能分布的均匀性,以二元硝酸盐为基盐、SiO2(30 nm)为纳米材料,采用高温熔融法制备纳米熔盐,在纳米熔盐不同位置处采集9个样品,对其传热储热性能进行表征。结果表明:样品SS6的比热最高,固态区比热比9个纳米熔盐样品的平均比热高11.69%,液态区比热比9个纳米熔盐样品的平均比热高12.62%;样品SS7的比热最低,固态区比热比9个纳米熔盐样品的平均比热低9.01%,液态区比热比9个纳米熔盐样品的平均比热低9.61%。样品SS6的熔化潜热最高,比9个纳米熔盐样品的平均熔化潜热高5.44%;样品SS7的熔化潜热最低,比9个纳米熔盐样品的平均熔化潜热低5.94%。样品SS6的导热系数最高,比9个纳米熔盐样品的平均导热系数高19.84%;样品SS1的导热系数最低,比9个纳米熔盐样品的平均导热系数低19.13%。不同位置搅拌强度的差异造成纳米熔盐中云核的尺寸、分布及聚集程度不同,是导致纳米熔盐传热储热性能存在较大不均匀性的原因。
In order to study the homogeneity of heat transfer and thermal energy storage performance of molten salt nanofluids,a binary nitrate as base salt and SiO2(30 nm)as nano-material were used to prepare the molten salt nanofluids by high-temperature melting method.Nine samples were collected at different locations inside the molten salt nanofluids and characterized experimentally.Results show that in solid state the specific heat of the sample SS6 with the maximal specific heat is 11.69%higher than the average specific heat of the nine samples,while in liquid state the specific heat of the sample SS6 with the maximal specific heat is 12.62%higher than the average specific heat of the nine samples.In solid state the specific heat of the sample SS7 with the minimal specific heat is 9.01%lower than the average specific heat of the nine samples,while in liquid state the specific heat of the sample SS7 with the minimal specific heat is 9.61%lower than the average specific heat of the nine samples.The latent heat of melting of the sample SS6 with the maximal latent heat of melting is 5.44%higher than the average latent heat of melting of the nine samples,while the latent heat of melting of the sample SS7 with the minimal latent heat of melting is 5.94%lower than the average latent heat of melting of the nine samples.The thermal conductivity of the sample SS6 with the maximal thermal conductivity is 19.84%higher than the average thermal conductivity of the nine samples,while the thermal conductivity of the sample SS1 with the minimal thermal conductivity is 19.13%lower than the average thermal conductivity of the nine samples.The size,distrubution and aggregation degree of cloud nuclei in molten salt nanofluids are different due to the difference of stirring intensity at different positions,which is the reason for the large inhomogeneity of heat transfer and thermal energy storage performance of molten salt nanofluids.
作者
熊亚选
王慧慧
宋超宇
吴玉庭
马重芳
XIONG Yaxuan;WANG Huihui;SONG Chaoyu;WU Yuting;MA Chongfang(Key Laboratory of HVAC, Beijing University of Civil Engineering and Architecture, Beijing 100044, China;Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Ministry of Education, Beijing University of Technology, Beijing 100124, China)
出处
《中国科技论文》
CAS
北大核心
2022年第7期823-830,共8页
China Sciencepaper
基金
北京市教育委员会科学研究计划项目(KM201910016011)
北京市自然科学基金资助项目(3151001)。
关键词
无机盐
纳米熔盐
差示扫描量热法
激光闪光法
传热储热
均匀性
inorganic salt
molten salt nanofluid
differential scanning calorimetry
laser flash analysis
heat transfer and thermal energy storage
homogeneity
