聚光条件下纳米流体非均匀集热特性分析  

Analysis on solar collection characteristics of nanofluid under non-uniform concentrated radiation

作　　者：徐国英[1] 陈彩[1] 张小松[1] 陈伟[1] 

机构地区：[1]东南大学能源与环境学院,南京210096

出　　处：《东南大学学报（自然科学版）》2016年第6期1221-1226,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51676046);"十二五"国家科技支撑计划资助项目(2014BAJ01B05-2)

摘　　要：研究了一种采用纳米流体直接吸收太阳辐射的聚光型中温集热器.建立了纳米流体集热过程能量传递和聚光器辐射热流分布的数学模型,测试了添加不同质量分数纳米颗粒的Cu O-导热油纳米流体的吸光系数,进而对非均匀聚光条件下纳米流体直接吸收式集热器（NDASC）特性进行了CFD模拟.分析了40-150℃范围内不同纳米颗粒质量分数对NDASC管内温度分布和集热效率的影响规律.结果表明：NDASC集热管周向温差明显低于传统间接吸收式集热器,但随着纳米颗粒质量分数的提高,纳米流体吸光系数增大,管内温度分布的不均匀性加剧;集热效率则随纳米颗粒质量分数的增大呈现先升后降的趋势,得出了集热性能最佳的纳米颗粒质量分数范围.A nanofluid-based direct absorption solar collector （NDASC） operated with a parabolic trough concentrator was studied. The radiation transmission and the heat transfer mechanism within the nanofluid were mathematically modeled, and the spectral absorption properties of CuO/oil nanofluid with different mass fractions of CuO nanoparticles were investigated. Then, performance characteristics of the NDASC operated under non-uniform concentrated solar radiation flux were numerically simulated. The influences of mass fraction of nanoparticles on the NDASC temperature dis-tribution of NDASC and collection efficiency were analyzed at temperature from 40 to 150 ℃. Results show that the temperature difference on the inner tube wall of NDASC is much lower than that of a conventional solar collector employing coated tube. With the increase of the mass fraction of nanoparticles, the absorption coefficient of nanofluid increases, and the temperature distribution in the NDASC becomes more non-uniform,but the collection efficiency first increases and then decreases. Furthermore, the optimum mass fraction of the nanofluid is obtained to achieve the highest collection efficiency.

关 键 词：纳米流体 太阳能集热器 聚光 集热效率 温度分布 

分 类 号：TK513[动力工程及工程热物理—热能工程]