TPD法测量高速空气流乙烯非预混火焰适用性研究

EXPERIMENTAL INVESTIGATIONS ON THE FEASIBILITY OF TPD METHOD FOR SOOT VOLUME FRACTION MEASUREMENT IN HIGH-SPEED AIR FLOW NONPREMIX FLAME

本文主要研究了基于热泳沉积机理的碳黑颗粒沉积法(TPD方法)在高速空气流非预混火焰中测量碳黑容积份额的适用性问题。传统的TPD方法都只是在低速空气流非预混火焰中应用,而且用于数据分析的碳黑沉积率表达式只考虑了热泳沉积机理。我们通过构造出一个新的从热电偶节点发射率变化率中直接得到碳黑沉积率表达式,分析了碳黑沉积率在沉积初始阶段随时间的变化。发现在高速空气流火焰中,热泳沉积机理并不是推动碳黑颗粒在热电偶节点表面沉积的主要机理,但碳黑沉积率还是明显呈现出了和碳黑容积份额的正相关关系。

The aim of the present paper is to validate the feasibility of thermocouple particle dcnsitometry （TPD） method for soot volume fraetion measurement in non-premixed, Ethylene/air flame with high-speed air flow. In the traditional TPD method, the expression for the soot deposition rate is only based on the thermophoresis diffusion mechanism, and it is only suitable for the flame with low air flow speed. A new relationship between the changing rate of junction emissivity and the soot deposition rate is established based on the junction energy balance expression, and the soot deposition rate is obtained in the early stage of deposition from experiments. It is found that. for the non-premixed flame with high-speed air flow, the thermophoresis diffusion is not the dominant mechanism of soot particles mass transfer to the junction surface, and a positive correlation is revealed between the soot deposition rate and the soot volume fraction.