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采用热松弛时间表征微纳米含碳粒子受热瞬间热扰动和热响应存在的时间迟滞,同时结合Kn数判断受热粒子所处的流动区域修正空气导热系数,建立亚微米碳粒的单相延迟双曲型瞬态激光诱导辐射传热传质模型,分析碳粒子经高能脉冲激光照射前后其温度与激光诱导辐射光谱强度的时域变化特征。重点讨论了热松弛时间与激光能量等参数对不同粒径尺度的碳粒激光诱导辐射光谱信号的影响。结果表明,热松弛时间值越大,入射激光能量越高,粒径越小,受热颗粒的激光诱导辐射光谱信号振荡幅度越强,非傅里叶效应越显著,这为采用激光诱导辐射技术进行高温环境亚微米量级含碳微粒的定量测量研究提供理论依据。
The thermal relaxation time is used to characterize the time delay of the thermal disturbance and the thermal response of the micro-nano carbon-containing particles. The Kn-number is used to determine the flow area where the heated particles are located to correct the air thermal conductivity and to establish the single-phase delayed hyperbolic Type transient laser-induced radiative heat and mass transfer model to analyze the time-domain variation characteristics of carbon particle temperature and laser-induced radiation before and after high-energy pulsed laser irradiation. The effects of parameters such as thermal relaxation time and laser energy on the laser induced radiation spectra of carbon particles with different particle sizes were discussed. The results show that the larger the thermal relaxation time, the higher the incident laser energy and the smaller the particle size. The stronger the amplitude of the laser-induced radiation spectrum signal is, the more significant the non-Fourier effect is. This is the result of laser-induced radiation The theoretical basis for quantitative measurement of submicron carbonaceous particles in high temperature environment is provided.