直接吸收式太阳能集热纳米流体辐射特性实验研究

Experimental Investigation on Radiation Characteristic of Nanofluids for Direct Absorption Solar Thermal Energy Systems

采用两步法配制了cu-H2O、Co-H2O、MWCNT-H2O三种纳米流体，利用紫外一可见-近红外分光光度计结合积分球原理测试了不同粒径、不同质量分数、不同光程的上述纳米流体在太阳能全波段（250nm〈A〈2500nm）的透射率。结果表明，三种纳米流体的透射率都要比水的小，并且纳米流体的透射率随着粒径的增大以及质量分数的增加而降低，随着光程的减小而增大。在相同质量分数条件下，MWCNT—H2O透射率最小，在250—775nm波段，co—H2O的透射率要高于cu—H2O的，而在775～1370nm波段，co—H2O的透射率要低于cu-H2O的，表明不同粒子在不同波段具有不同的光吸收性能。

In this article, Cu-H2 O, Co-H2 O, MWCNT-H20 nanofluids were prepared through two-step method. The transmittance of nanofluids over solar spectrum （250 to 2500nm） was measured by the UV-Vis-NIR spectrophotometer based on integrating sphere princi- ple. The factors of various particle size, mass fraction and optical path influencing transmittance of nanofluids were inves.tigated. The ex perimental results show that the transmittance of the three nanofluids is much less than that of deionized water. The transmittance de creased with the nanoparticle size and mass fraction increasing, but increased with the optical path length reducing. With the same mass fraction, the transmittance of MWCNT-H20 nanofluids is the minimum. The transmittance of Co-H20 nanofluids is higher than that of Cu- ll2 0 during 250 -775nm wavelength, while inverse during 775 - 1370nm wavelength. It indicates that different particle has diverse light absorption properties during different wavelength.