【摘要】：微尺度下輻射研究可采用數(shù)值與實驗研究方法。實驗研究常受限于實驗設(shè)備與操作環(huán)境。數(shù)值研究物理概念清楚,理論研究比較充分,簡化假設(shè)較少,能較準(zhǔn)確的反映實際的物理過程,其結(jié)果可作為進一步實驗研究的依據(jù)。因而本文主要采用數(shù)值研究的方法分析微尺度下的輻射換熱問題。輻射換熱屬于傳熱領(lǐng)域的一個重要分支,根據(jù)不同溫度物體間距離的不同,可以將輻射分成遠(yuǎn)場輻射與近場輻射。遠(yuǎn)場輻射可以通過斯蒂芬-波爾茲曼公式計算獲得,結(jié)果與物體間的距離無關(guān)。而近場輻射卻由于電磁波的耦合作用,隨著物體間距離減小輻射換熱量大大增加,并且與物體間距離呈六次方反比關(guān)系,同時可以通過改變物質(zhì)結(jié)構(gòu)、尺寸、材料等來改變物體間近場輻射換熱的大小與換熱的光譜區(qū)間。納米顆粒群間的輻射換熱屬于微尺度換熱范疇,在此,我們引入一種新型物質(zhì)結(jié)構(gòu),即半導(dǎo)體內(nèi)核金屬外殼構(gòu)成的復(fù)合結(jié)構(gòu)納米顆粒,通過改變物質(zhì)的半徑、體積分?jǐn)?shù)、陣列間的距離來控制物質(zhì)的輻射換熱特性。納米顆粒群的消光作用可以分為吸收作用和散射作用,依據(jù)顆粒尺寸和體積分?jǐn)?shù)的不同,納米顆粒間的散射可以分為獨立散射與非獨立散射,近場輻射為非獨立散射情況下顆粒間的輻射耦合作用提供了一種解釋。本文第一章介紹了本論文的研究背景以及國內(nèi)外的研究現(xiàn)狀。第二章引入輻射換熱基礎(chǔ)理論的介紹,包括Maxwell電磁理論與電介質(zhì)函數(shù)模型,分析溫度對介質(zhì)電介質(zhì)函數(shù)的影響以及不同電介質(zhì)函數(shù)模型的區(qū)別,基于Maxwell原理的波動電動力學(xué)方法得到了兩個平面間和兩個顆粒間的輻射換熱特性和光譜變化情況。第三章在第二章的基礎(chǔ)上,得到了殼核結(jié)構(gòu)納米陣列間的近場輻射作用,包括殼核結(jié)構(gòu)納米顆粒陣列間的近場輻射和殼核結(jié)構(gòu)納米線陣列間的近場輻射,并依次計算了相應(yīng)的近場輻射熱傳導(dǎo)。第四章則主要分析殼核結(jié)構(gòu)顆粒群的消光效應(yīng),首先介紹顆粒輻射的散射與吸收理論,依次介紹與消光效應(yīng)相關(guān)的Mie散射理論、基于射線追蹤的蒙特卡洛方法、Quasi-static近似的Rayleigh散射方法,在以上理論研究的基礎(chǔ)上,得到了不同尺度、體積分?jǐn)?shù)、材料的納米顆粒群的消光效應(yīng)和輻射透射率。研究發(fā)現(xiàn)殼核結(jié)構(gòu)的納米線與納米顆粒是一種很好的強化換熱物質(zhì)結(jié)構(gòu),相信相應(yīng)的數(shù)值計算結(jié)果對微納尺度下輻射換熱的進一步研究有一定的參考意義。
[Abstract]:Numerical and experimental methods can be used to study radiation at microscale. Experimental research is often limited by experimental equipment and operating environment. The physical concept of numerical research is clear, the theoretical research is more adequate, the simplified hypothesis is less, and the actual physical process can be accurately reflected. The results can be used as the basis for further experimental research. Therefore, the numerical method is mainly used to analyze the radiation heat transfer problem in the micro scale. Radiation heat transfer is an important branch of heat transfer field. According to the distance between objects at different temperatures, radiation can be divided into far-field radiation and near-field radiation. The far-field radiation can be calculated by Steff-Boltzmann formula and the results are independent of the distance between the objects. However, the near-field radiation increases greatly with the decrease of the distance between the objects due to the coupling of electromagnetic waves, and is inversely proportional to the distance between the objects. At the same time, it can be changed by changing the structure and size of the matter. Materials, etc., to change the magnitude and spectral range of near-field radiation heat transfer between objects. The radiation heat transfer between nanoparticles belongs to the category of microscale heat transfer. In this case, we introduce a new kind of material structure, that is, the composite structure of the semiconductor core metal shell, by changing the radius and volume fraction of the matter. The distance between arrays controls the radiative heat transfer characteristics of matter. The extinction action of nanoparticles can be divided into absorption and scattering. According to the difference of particle size and volume fraction, the scattering between nanoparticles can be divided into independent scattering and non-independent scattering. Near-field radiation provides an explanation for the radiation coupling between particles in the case of non-independent scattering. The first chapter of this paper introduces the research background and domestic and foreign research status. The second chapter introduces the basic theory of radiation heat transfer, including Maxwell electromagnetic theory and dielectric function model, analyzes the influence of temperature on dielectric function and the difference between different dielectric function models. The radiative heat transfer characteristics and spectral variations between two planes and two particles are obtained by the wave electrodynamics method based on Maxwell principle. In chapter 3, based on the second chapter, we get the near field radiation between the shell core nanoarrays, including the near field radiation between the shell core structure nanoparticles array and the shell core structure nanowire array. The corresponding near field radiation heat conduction is calculated in turn. In the fourth chapter, the extinction effect of particle group in shell core structure is analyzed. Firstly, the scattering and absorption theory of particle radiation is introduced, and then the Mie scattering theory related to extinction effect is introduced, and the Monte Carlo method based on ray tracing is introduced. Based on the theoretical study above, the Quasi-static approximation Rayleigh scattering method is used to obtain the extinction effect and radiative transmittance of different scales, volume fraction, nano-particle groups of materials. It is found that the nanowires and nanoparticles of the shell core structure are a good enhancement of heat transfer material structure. It is believed that the corresponding numerical results are useful for the further study of radiation heat transfer at the micro- and nanoscale scale.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.1

【參考文獻】

相關(guān)期刊論文 前4條

1 方哲宇;劉丹;王笑;黃姍;朱星;;近場光學(xué)顯微技術(shù)的進展及其應(yīng)用[J];電子顯微學(xué)報;2008年01期

2 殷金英;劉林華;;氧化鋁粒子光學(xué)常數(shù)的尺度效應(yīng)[J];工程熱物理學(xué)報;2007年02期

3 杜永成;楊立;;輻射傳輸介質(zhì)散射相函數(shù)的蒙特卡洛算法[J];光譜學(xué)與光譜分析;2011年07期

4 胡永紅,容建華,劉應(yīng)亮,滿石清;金屬介電核殼結(jié)構(gòu)復(fù)合材料的制備、性質(zhì)及應(yīng)用[J];化學(xué)進展;2005年06期

相關(guān)碩士學(xué)位論文 前1條

1 江樂;球形納米粒子與半無限大介質(zhì)的近場輻射換熱研究[D];哈爾濱工業(yè)大學(xué);2007年

，

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