水平管煤粉气力输送流型实验研究

Experimental Study on Flow Patterns in Horizontal Pneumatic Conveying of Pulverized Coal Powders

通过建立加压煤粉气力输送试验台,采用电容成像系统重点研究水平管中表观气速、煤粉流量以及输送背压对管道内煤粉流动形态的影响。结果表明:随着表观气速的减小,先后出现悬浮流、不同滑动层高度的线状流、沙丘流以及移动栓流;随着煤粉流量的增大,管内煤粉浓度增大,向移动栓流状态发展,移动栓出现的频率以及移动栓长有所增大;随着输送背压的增大,管内煤粉浓度减小,向悬浮流状态发展,在输送背压较大时,较小的表观气速可形成移动栓流。

An experimental study on tbe pneumatic conveying of pulverized coal powders at elevated pressures was carried out. The influences of superficial gas velocity, mass flow rate and conveying back pressure on the flow patterns were investigated with electrical capacitance tomography. The results indicate that four flow patterns, i. e., suspension flow, stratified flow, dune flow and moving bed flow appear as the superficial gas velocity decreases. The flow pattern tends to moving bed flow as the mass flow rate increases, as well as the increases in frequency and the length of moving bed. The suspension flow appears with the increase in conveying back pressure and the decrease in mass flow rate. The moving bed flow is more likely to form with the lower superficial gas velocity when the conveying back pressure is high.