用压降法测量管内颗粒浓度和风速方法的研究

An Investigation of the Measurement of Solid Concentration and Air Velocity in Pneumatic Pipes Using the Pressure Drop Method

根据两相流压降与颗粒浓度具有的确定的依赖关系 ,提出了压降法测量管道颗粒浓度和风速的一般形式和特殊形式。通过对压降法不同形式的分析 ,找到了各自在测量上的特点及相互间的差别。指出在同一管线上选择送粉特性有差异的两段管道应用压降法的一般形式 ,可不破坏原有管线及其阻力特性 ,特别适合于采用乏气送粉和直吹式制粉系统的火电厂现场使用。建立了试验及在线测量系统并进行了试验 ,论证了压降法测量的可行性。

Based on the definitive depending relationship between pressure drop and solid concentration in air solid flow, the general form pressure drop method for the measurement of air velocity and solid concentration in the pipe is put forward. The concentration-pressure drop method and the velocity-pressure drop method are two special forms of this kind method. With the analysis to the different forms of pressure drop method, the characteristics and differences of each ones about measurement are obtained. It is pointed out that the original pipes and resistance characteristics would not be modified if the general form pressure drop method was adopted by selecting two pieces of pipes with the different delivering powder characteristics in the same pipe. Especially it is very suitable to the heat-engine plants using vant fan or direct-fired systems. The experimental results show this method is workable by means of the on line metering system.