In particle sizing by light extinction method, the regularization parameter plays an important role in applying regularization to find the solution to ill-posed inverse problems. We combine the generalized cross-valid...In particle sizing by light extinction method, the regularization parameter plays an important role in applying regularization to find the solution to ill-posed inverse problems. We combine the generalized cross-validation （GCV） and L-curve criteria with the Twomey-NNLS algorithm in parameter optimization. Numerical simulation and experimental validation show that the resistance of the newly developed algorithms to measurement errors can be improved leading to stable inversion results for unimodal particle size distribution.展开更多
One of the difficulties encountered in the study of dusty plasmas is related to the knowledge of the size of the dust particles present. A variety of sources, physical and chemical mechanisms of formation, causes a wi...One of the difficulties encountered in the study of dusty plasmas is related to the knowledge of the size of the dust particles present. A variety of sources, physical and chemical mechanisms of formation, causes a wide variety of sizes and morphologies of dust. The diameter of a dust will not be unique but spread over several orders of magnitude. Its distribution in number, surface, mass or volume is called distribution. It is important to know this distribution in particle size because it strongly impacts the physical and radiative processes. To have a dust distribution in situ is very difficult;the reverse method can identify the particle populations from light extinction measures. In this study, we present an inversion procedure with a Tikhonov regularization dedicated to the determination of volume size distribution (V-PSD) from extinction measurements corresponding to the different wavelengths obtained by the Extinction Spectrometry technique.展开更多
搭建蒸汽测试实验系统,结合经典ECAH(Epstein-Carhart-Allegra-Hawley)理论模型,提出三频率超声波声衰减颗粒测量方法,采用中心频率为22,40和200 k Hz的超声波开展蒸汽液滴粒径和含量(体积分数)的超声法测量实验,在相同工况下基于光散...搭建蒸汽测试实验系统,结合经典ECAH(Epstein-Carhart-Allegra-Hawley)理论模型,提出三频率超声波声衰减颗粒测量方法,采用中心频率为22,40和200 k Hz的超声波开展蒸汽液滴粒径和含量(体积分数)的超声法测量实验,在相同工况下基于光散射法的原理,同时开展多波长消光法和激光散射法对比测试研究。实验结果表明:超声衰减法测得蒸汽液滴粒径和含量与消光法和激光散射法的测量值接近,超声衰减法有望用于气液两相流中蒸汽液滴粒径以及含量(湿度)参数的在线监测。展开更多
基金The present work is supported by National Science Foundation of China （NSFC 50376041）the National High Technology Development 863 Program （2006AA03Z349）the ShuGuang project of Shanghai Educational Development Foundation （04SG49）, which are gratefully acknowledged.
文摘In particle sizing by light extinction method, the regularization parameter plays an important role in applying regularization to find the solution to ill-posed inverse problems. We combine the generalized cross-validation （GCV） and L-curve criteria with the Twomey-NNLS algorithm in parameter optimization. Numerical simulation and experimental validation show that the resistance of the newly developed algorithms to measurement errors can be improved leading to stable inversion results for unimodal particle size distribution.
文摘One of the difficulties encountered in the study of dusty plasmas is related to the knowledge of the size of the dust particles present. A variety of sources, physical and chemical mechanisms of formation, causes a wide variety of sizes and morphologies of dust. The diameter of a dust will not be unique but spread over several orders of magnitude. Its distribution in number, surface, mass or volume is called distribution. It is important to know this distribution in particle size because it strongly impacts the physical and radiative processes. To have a dust distribution in situ is very difficult;the reverse method can identify the particle populations from light extinction measures. In this study, we present an inversion procedure with a Tikhonov regularization dedicated to the determination of volume size distribution (V-PSD) from extinction measurements corresponding to the different wavelengths obtained by the Extinction Spectrometry technique.
文摘搭建蒸汽测试实验系统,结合经典ECAH(Epstein-Carhart-Allegra-Hawley)理论模型,提出三频率超声波声衰减颗粒测量方法,采用中心频率为22,40和200 k Hz的超声波开展蒸汽液滴粒径和含量(体积分数)的超声法测量实验,在相同工况下基于光散射法的原理,同时开展多波长消光法和激光散射法对比测试研究。实验结果表明:超声衰减法测得蒸汽液滴粒径和含量与消光法和激光散射法的测量值接近,超声衰减法有望用于气液两相流中蒸汽液滴粒径以及含量(湿度)参数的在线监测。
