本文選題：微納尺度導(dǎo)熱 + 超快速激光加熱��； 參考：《山東大學(xué)》2015年博士論文

【摘要】：超快速脈沖激光加熱技術(shù)已被廣泛應(yīng)用于材料科學(xué)、納米技術(shù)等諸多領(lǐng)域,而激光加熱引起的納米尺度的導(dǎo)熱規(guī)律仍有待進(jìn)一步探索,并成為該技術(shù)進(jìn)一步發(fā)展的制約因素。許多微電子元件的尺寸已達(dá)到納米級(jí),為了設(shè)計(jì)其散熱系統(tǒng),必須深入研究微納尺度導(dǎo)熱的機(jī)理。對(duì)于微納尺度導(dǎo)熱問(wèn)題,實(shí)驗(yàn)、理論和數(shù)值結(jié)果均表明暗含傳播速度無(wú)限大假設(shè)的傳統(tǒng)傅立葉定律不再適用。因此,探索微納尺度導(dǎo)熱規(guī)律具有重要的理論價(jià)值和應(yīng)用價(jià)值。本文基于Cattaneo-Vernotte(CV)導(dǎo)熱模型、雙相滯(DPL)導(dǎo)熱模型和體現(xiàn)尺度效應(yīng)的改進(jìn)的CV導(dǎo)熱模型,應(yīng)用解析方法對(duì)超快速激光加熱引起的導(dǎo)熱問(wèn)題開(kāi)展了系統(tǒng)的研究。并應(yīng)用格子Boltzmann方法(LBM)數(shù)值模擬了超快速激光加熱問(wèn)題和微納尺度熱點(diǎn)引起的導(dǎo)熱問(wèn)題。本文首先基于傅立葉定律和CV導(dǎo)熱模型,研究了超快速激光加熱金薄膜引發(fā)的薄膜內(nèi)部的導(dǎo)熱問(wèn)題,并將兩個(gè)模型給出的結(jié)果進(jìn)行了比較。研究結(jié)果表明,在CV導(dǎo)熱模型中,熱是以波動(dòng)方式傳輸?shù)?而不再是基于傅立葉定律的擴(kuò)散傳輸方式,因此消除了熱擾動(dòng)傳播速度無(wú)限大的缺陷,并得到了不同克努森數(shù)下“熱波”在薄膜內(nèi)部傳播的無(wú)量綱速度。同時(shí)發(fā)現(xiàn)在絕熱邊界條件下,當(dāng)系統(tǒng)達(dá)到穩(wěn)定后,溫度會(huì)隨著克努森數(shù)的增加而升高。基于DPL導(dǎo)熱模型對(duì)超快速激光加熱金薄膜的一維導(dǎo)熱問(wèn)題進(jìn)行了研究。結(jié)果表明,增大溫度梯度遲滯時(shí)間與熱流密度遲滯時(shí)間的比值會(huì)降低薄膜被激光加熱一端的溫度峰值,并縮短系統(tǒng)達(dá)到穩(wěn)定狀態(tài)的時(shí)間�；贒PL導(dǎo)熱模型給出了在激光加熱薄膜的導(dǎo)熱過(guò)程中“熱波”發(fā)生的必要條件。另外發(fā)現(xiàn)當(dāng)溫度梯度遲滯時(shí)間大于熱流密度遲滯時(shí)間時(shí),導(dǎo)熱過(guò)程將不再發(fā)生熱波現(xiàn)象,這一結(jié)論既符合本文的計(jì)算結(jié)果,又驗(yàn)證了Tang的結(jié)論。同時(shí)研究了在滑移邊界條件下,表面調(diào)節(jié)系數(shù)對(duì)薄膜內(nèi)溫度分布的影響,研究結(jié)果表明,受加熱表面的溫度會(huì)隨著表面調(diào)節(jié)系數(shù)的增加而降低。本文還基于DPL導(dǎo)熱模型研究了不同克努森數(shù)下薄膜內(nèi)部熱流密度的分布情況,結(jié)果表明,當(dāng)系統(tǒng)達(dá)到穩(wěn)定狀態(tài)時(shí),熱流密度的值隨著克努森數(shù)的增加而增大。在微納尺度導(dǎo)熱系統(tǒng)中,導(dǎo)熱系數(shù)與系統(tǒng)的特征長(zhǎng)度緊密相關(guān)。因此本文基于體現(xiàn)尺度效應(yīng)的改進(jìn)的CV導(dǎo)熱模型對(duì)超快速脈沖激光加熱金薄膜的導(dǎo)熱問(wèn)題進(jìn)行了研究。在與CV導(dǎo)熱模型給出的結(jié)果的比較中發(fā)現(xiàn),在改進(jìn)的CV導(dǎo)熱模型中熱波的波峰并不出現(xiàn)在薄膜的內(nèi)部,而是始終位于受加熱邊界。還發(fā)現(xiàn)兩個(gè)模型所得無(wú)量綱速度值之間的大小取決于克努森數(shù)是否大于1.1027。在與DPL導(dǎo)熱模型給出的結(jié)果進(jìn)行比較時(shí),發(fā)現(xiàn)兩種模型所得到的溫度分布存在較大差別,而且隨著克努森數(shù)和DPL導(dǎo)熱模型中的溫度梯度遲滯時(shí)間的增大,兩者的差別愈發(fā)明顯。本文利用LBM數(shù)值模擬了激光加熱硅薄膜的一維導(dǎo)熱問(wèn)題,結(jié)果表明,在過(guò)渡區(qū)由激光加熱引起的薄膜內(nèi)部的能量是以波動(dòng)的形式進(jìn)行傳輸?shù)?且隨著克努森數(shù)的增大,能量密度峰值變高。利用激光分別對(duì)薄膜的兩側(cè)進(jìn)行加熱時(shí),發(fā)現(xiàn)由激光在薄膜兩側(cè)施加擾動(dòng)引起的熱波在薄膜內(nèi)相遇時(shí),會(huì)引發(fā)能量的劇烈增強(qiáng)。在與傅立葉定律和CV導(dǎo)熱模型給出的結(jié)果的比較中,發(fā)現(xiàn)傅立葉定律不能展示能量的波動(dòng)傳輸方式,且會(huì)嚴(yán)重低估薄膜內(nèi)產(chǎn)生的能量密度峰值。CV導(dǎo)熱模型雖然能夠展示能量的波動(dòng)傳輸形式和熱波在相遇后的能量增強(qiáng)現(xiàn)象,但會(huì)低估能量增強(qiáng)的幅度。此外,本文還提出了通過(guò)控制激光作用于薄膜兩側(cè)的時(shí)間差,從而調(diào)節(jié)薄膜內(nèi)能量最大值產(chǎn)生位置的方法,這對(duì)激光加熱技術(shù)具有一定的指導(dǎo)意義。本文最后利用LBM研究了絕緣體上硅(SOI)晶體管的硅薄膜中納米尺寸熱點(diǎn)引發(fā)的導(dǎo)熱問(wèn)題。結(jié)果表明,在過(guò)渡區(qū)能量是以波動(dòng)的形式進(jìn)行傳輸?shù)?并且邊界條件對(duì)薄膜內(nèi)能量的高低具有十分重要的影響。
[Abstract]:Ultra fast pulse laser heating technology has been widely used in materials science, nanotechnology and many other fields, and the thermal conductivity of nanoscale caused by laser heating remains to be further explored, and it has become a restriction factor for the further development of this technology. It is necessary to study the mechanism of micro nano scale heat conduction. For the micro and nanoscale heat conduction problem, the experimental, theoretical and numerical results show that the traditional Fu Liye's law with infinite propagation velocity is no longer applicable. Therefore, it is of great theoretical value and application value to explore the law of micro and nanoscale heat conduction. This paper is based on Cattaneo-Vernotte (CV). The heat conduction model, the dual phase hysteresis (DPL) heat conduction model and the improved CV heat conduction model, which reflect the scale effect, have been applied to the systematic study of the heat conduction problems caused by ultra fast laser heating, and the lattice Boltzmann method (LBM) is used to simulate the heat conduction problems caused by the ultra fast laser heating and the micro and nanoscale hot spots. In this paper, based on Fu Liye's law and the CV heat conduction model, the heat conduction in the film caused by a ultra fast laser heating gold film is studied. The results of the two models are compared. The results show that in the CV heat conduction model, the heat is transmitted in a wave mode, and is no longer a diffusion mode based on Fu Liye's law. Therefore, the infinite propagation velocity of thermal disturbance is eliminated, and the dimensionless velocity of the "hot wave" propagating in the film is obtained under different Knudsen numbers. At the same time, it is found that under the adiabatic boundary condition, when the system reaches stability, the temperature will rise with the increase of the Knudsen number. Based on the DPL heat conduction model, the ultra fast laser is heated to the gold thin. The one-dimensional heat conduction problem of the film has been studied. The results show that increasing the ratio of the hysteresis time of the temperature gradient and the delay time of the heat flux will reduce the temperature peak of the film being heated at the end of the laser and shorten the time of the system to reach the stable state. Based on the DPL heat conduction model, the heat wave in the heat conduction process of the excited light heating film is given. It is also found that the heat wave will no longer occur when the temperature gradient lag time is greater than the delay time of the heat flux. This conclusion is not only in accordance with the results of this paper, but also verifies the conclusion of Tang. At the same time, the influence of the surface adjustment coefficient on the temperature distribution in the film under the slip boundary condition is studied. The results show that the temperature of the heated surface decreases with the increase of the surface adjustment coefficient. In addition, based on the DPL heat conduction model, the distribution of heat flux in the thin films under different Knudsen numbers is studied. The results show that when the system reaches a stable state, the value of the heat flux increases with the increase of the number of Knudsen. In the heat conduction system, the thermal conductivity is closely related to the characteristic length of the system. Therefore, based on the improved CV heat conduction model which reflects the scale effect, this paper studies the heat conduction problem of the ultra fast pulse laser heating gold film. In comparison with the results obtained from the CV heat conduction model, it is found that the wave peak of the thermal wave in the improved CV heat conduction model is also found. It does not appear in the interior of the film, but always located at the heated boundary. It is also found that the size of the dimensionless velocity between the two models depends on whether the number of the 1.1027. is larger than the results given by the DPL heat conduction model, and it is found that the temperature distribution of the two models is very different, and with the Knudsen number. The difference between the two is more obvious with the increase of the temperature gradient delay time in the DPL heat conduction model. This paper uses the LBM numerical simulation to simulate the one-dimensional heat conduction problem of the laser heated silicon thin film. The results show that the energy in the thin film caused by laser heating is transmitted in a wave form in the transition zone, and with the increase of the Knudsen number, The peak of the energy density is higher. When the two sides of the film are heated by laser, it is found that the heat wave caused by the disturbance caused by the disturbance of the laser on both sides of the film will cause the intense enhancement of the energy. In comparison with the results given by Fu Liye's law and the CV heat conduction model, it is found that Fu Liye's law can not show the wave of energy. The dynamic transmission mode, and it will seriously underestimate the peak of the energy density in the thin film,.CV heat conduction model, although it can show the wave propagation form of energy and the energy enhancement after the heat wave at the meeting, but will underestimate the amplitude of the energy enhancement. In addition, this paper also proposes to adjust the time difference between the two sides of the film by controlling the excitation of the excitation light, thus adjusting the thin film. The method of producing the position of the maximum energy in the film has a certain guiding significance for the laser heating technology. In this paper, the heat conduction problem caused by the nano size hot spots in the silicon film on the silicon (SOI) transistor on the insulator is studied by LBM. The results show that the energy in the transition region is transmitted in the form of wave, and the boundary condition is the same. The energy level in the film has a very important influence.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TK124

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本文編號(hào)：1925975