纳米流体辐射特性理论分析与实验研究

随着人类社会的飞速发展，能源紧缺、环境污染问题日益严重。当下，开发新能源、发展新能源技术已成为全球各国首要能源策略。作为一种清洁能源，太阳能蕴藏着巨大能量，太阳能利用和相关技术在世界范围内也引起了广泛关注。基于纳米流体的太阳能直接吸收式集热装置能够耦合光伏与光热技术，有利于提高太阳能综合利用的效率。由于纳米流体辐射理论对于开发新的光伏热实验平台具有重要的作用，而纳米流体辐射特性研究仍处于起步阶段，所以对于纳米流体辐射规律及机理的研究具有重要的意义。首先综述了纳米流体辐射特性的研究现状，并对纳米流体的辐射特性进行了理论研究，进而采用瑞利散射模型和Mie(米氏)模型对纳米流体最重要的辐射特性之一的透射率进行了理论分析；而后运用实验进行对比验证，分析不同理论模型与实验数据间的吻合性。结果表明：Mie模型比瑞利散射模型更加准确，在光伏热实验平台开发利用中具有更好的适用性。该研究旨在利用纳米颗粒改变流体对太阳能的辐射特性，探索一种实际设计时纳米流体辐射特性简易高效的计算准则，并得到影响纳米流体辐射特性的重要因素之一的体积分数的变化规律，从而提高太阳能直接吸收式集热装置的太阳能利用率。纳米流体辐射特性理论的分析与研究，有利于促进纳米技术在太阳能领域的应用，提高太阳能的综合利用效率。

Theoretical and Experimental Study on Radiation Characteristics of Nanofluids

With the rapid development of modern society, energy shortage and environmental pollution are becoming increasingly serious. Nowadays, investigations on new energy and new energy technology are commonly listed as a primary energy strategy worldwide. As a clean energy, solar energy is enormous in amount and the utilization of solar energy and related technology has attracted widespread concern around the world. Photovoltaic and photovoltaic heat technology can be coupled with nanofluid-based solar direct absorption thermal collector, which is an important means to improve the efficiency of comprehensive utilization of solar energy. Because nanofluids radiation theory play an important role in the development of new photovoltaic-thermal experimental platform and study on radiation characteristics of nanofluids is still in the initial stage, it is of great significance for the study of the law and mechanism of nanofluids radiation. In this paper, firstly, recent researches of nanofluid radiation characteristics were reviewed. The radiation characteristics of nanofluids were investigated theoretically and then the Rayleigh scattering model and the Mie model were used to analyze the critical radiation characteristics-transmittances of the nanofluids. Furthermore, the consistency between different theoretical models and experimental datum was studied by contrast verification between experiments and theory calculation. The conclusions showed that Mie model performed better than Rayleigh scattering model and express a better applicability in the development of photovoltaic thermal experimental platform. The purpose of this paper was using nanoparticles to change the radiation characteristics of the fluid while exploring a simple and efficient calculation criterion of the nanofluid radiation characteristics in practical design. Besides, the principle of the volume fraction which is one of the important factors for nanofluid radiation characteristics was obtained. Consequently, solar energy utilization rate of nanofluid-based solar direct absorption thermal collector would be improved. This theoretical study on radiation characteristics of nanofluids was expected to prompt on the application of nanotechnology in the field of solar energy and improve the efficiency of comprehensive utilization of solar energy.