微尺度碳粒的激光诱导辐射非傅里叶现象分析

Analysis of Non-Fourier Effect During Laser-Induced Radiation of Micro Scale Carbon Particulates

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。

A numerical model of time-resolved laser-induced radiation model of micro-scale carbon particulates based on non-Fourier heat diffusion is developed, through adapting thermal relaxation time to present time lag between thermal disturbance and response inside particles, as well as correcting air Conductivity coefficient via K,, number to judge flux region of heated particles. Theoretical temperature and radiation signal profiles of heated carbon particulate are presented, in order to discuss the effect of radiation signals of micro-scale particles on different thermal relaxations and laser fluences. The results show non-Fourier phenomenon becomes obvious in radiation signals, in the case of high thermal relaxation, high laser fluence, and small particles. The discussion of the numerical results provides guidance for laser-induced radiation technique measuring the concentration and size of micro-scale carbon particulates in high temperature environment.