粉尘浓度测量装置利用涡流发生效应的优化研究

Optimization Research of Effect of Vortex by Measuring Device of Dust Concentration

对现阶段电荷感应法测量粉尘浓度不够精确的问题进行了研究。依据涡流发生效应和文丘里效应,对现有环状粉尘传感器的测量管道进行改造。通过在文丘里管道的喉道中间段不同对称位置加入三片三角形涡流发生器,使气流通过管道时不易产生气体分离效应;在发生器尾部产生空气旋涡,使得环式静电传感器所感应的电荷量增大。利用PROE 5.0软件建立所设计管道3D模型,并利用Fluent软件对改进的管道进行气固两相流仿真,获得改进管道内粉尘颗粒速度分布云图及喉道段内粉尘的速度值。使用环形静电传感器的数学模型,分别计算了文丘里管道和改进管道在不同粒径比下的感应电荷量。结果表明:改进管道的结构在实验中使得感应电荷量大幅提高,在各阶段测得感应电荷量提高20%以上。通过试验可知,在各个浓度情况下测量精度得到了较大的提升,大气监测和燃煤电厂粉尘浓度在线测量精度都有所提高。

The problem that the charge induction method is not accurate enough to measure the concentration of dust at present is studied.According to the eddy current generation effect and the Venturi effect,the measurement pipe of the existing ring dust sensor is modified.Three triangular vortex generators are added in the middle section of the throat of Venturi pipeline at different symmetrical positions,so that the air flow through the pipeline is not easy to produce gas separation effect,and air vortexes are generated at the end of the generator,so that the amount of charge induced by the ring electrostatic sensor increases.PROE 5.0 software was used to establish a 3D model of the sub-design pipeline,and Fluent software is used to simulate the gas-solid two-phase flow of the improved pipeline to obtain the dust particle velocity distribution nephogram in the improved pipeline and the dust velocity value in the throat segment.Using the mathematical model of ring electrostatic sensor,the induced charge of Venturi pipe and modified pipe under different particle size ratio are calculated respectively.The results show that the induced charge is increased by more than 20%in each stage.In this experiment,the measurement accuracy has been greatly improved in various concentrations,and the accuracy of the atmospheric monitoring and the online measurement of dust concentration in coal-fired power plants has been improved.