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基于光滑粒子动力学(SPH)方法发展起来的再生核粒子法(RKPM)是一种拉格朗日型无网格方法。该方法在处理复杂形体内流动、导热、相变、应力应变等多物理场耦合问题时获得了较广泛的应用,但在辐射传输中的适用性尚无研究。而高温半透明材料的相变过程,除以上多物理过程外还需要考虑辐射传输过程的影响。本文基于建立高温半透明颗粒相变过程光热力耦合过程统一的无网格模拟方法的目的,重点研究了RKPM模拟辐射传输的可行性问题。文中首先建立了辐射强度的RKPM拟合公式,然后建立了辐射传输方程的直接配点离散格式。计算了一维参与性灰介质的无量纲热流和无因次温度分布。通过和文献值对比,初步验证了RKPM能够模拟辐射传输方程,且具有较好的计算精度。 相似文献
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本文首先采用CFD-FASTRAN软件对RAM-CII钝锥体试验飞行器热化学非平衡绕流场参数进行了模拟分析,其次采取多温度模型结合逐线法获得非平衡绕流场吸收、发射系数,最终采用视在光线法LOS对RAM-CII飞行器全流场光辐射特性进行了模拟,分析表明:头部激波层紫外(0.2~0.4μm)辐射最强,要比尾迹流区高3个数量级以上,正侧向观测辐射强度比迎头观测时要大接近1个数量级;同一方向不同高度总的光谱辐射亮度差别不大,但正侧向观测的光谱辐射亮度比迎头方向观测略大;绕流场红外(2~5μm)辐射以CO2分子2.7、4.3μm谱带发射为主,但总体上看红外光谱辐射亮度相较于紫外要小3个数量级。 相似文献
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Refractive index of ionic liquids under electric field:Methyl propyl imidazole iodide and several derivatives 下载免费PDF全文
Ionic liquids have received wide attention due to their novel optoelectronic structures and devices as an optical means of regulating electricity.However,the quantitative testing and analysis of refractive index of ionic liquids under electric field are rarely carried out.In the present study,an experimental apparatus including a hollow prism is designed to measure the refractive indices of ionic liquids under different electric fields.Five groups of imidazole ionic liquids are experimentally investigated and an inversion is performed to determine the refractive indices under electric fields.The error propagation analysis of the apex angle and the minimum deflection angle are conducted,and the machining accuracy requirements of the hollow prism are determined.The results show that the refractive indices of imidazole ionic liquids change with the light wavelength,following a downward convex parabola.Furthermore,the refractive index decreases with the carbon chain length of ionic liquid at a given wavelength,presenting an order of C3MImI>C4MImI>C5MImI>C3MImBr>C3MImBF4.Notably,the refractive index of imidazole ionic liquid exhibits a nonlinear change with the applied voltage at 546 nm and a monotonical decrease at 1529 nm.Besides,the variation of refractive index at 1529 nm with the applied voltage is larger than that at 546 nm and 1013 nm.Importantly,the variation of refractive index is contrary to that of absorption coefficient under electric field.This study illustrates that the theory of electrode and carrier transport can be used to explain the law of variation of n–k value of ionic liquid under the electric field,and provides the support for the evaluation of physical properties of ionic liquids,the measurement of optical functional parameters and the regulation of electric–optic performances of optical devices. 相似文献
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针对硅基半导体电光热多场耦合特性及电调控问题,引入泊松方程和载流子连续性方程来计算载流子输运过程的浓度分布,利用德鲁德-洛伦兹公式和K-K关系式考虑载流子浓度变化对于光折射率和吸收系数的影响,并根据电磁耗散求解热沉积项。通过对半导体基本方程、电磁波动方程和能量方程的耦合方程组进行有限元求解,模拟并分析了电光热三者耦合作用下硅基半导体介电属性及光传输行为随外加电压、载流子初始浓度、换热系数等影响因素的变化规律。研究指出了半导体P区表面反射光电场模随外加电压的降低而升高,随换热系数的增大而降低的规律。利用该机制给出了对反射光强空间分布进行电热调控的方案。 相似文献
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