浓相正压气力输送流动特性研究和系统选择

浓相正压气力输送应用广泛,但存在计算繁琐、参数选择复杂等问题。通过分析目前气力输送方式及管道长度、流速、灰气质量比对管道压力的影响,阐述管道输送特性,找出堵管原因,并给出悬浮速度的选择方法,为浓相正压气力输送设计中的节能降耗提供指导性结论。对已有气力输送系统的计算理念进行归纳整理,提出"试算法"选择系统参数的方法:根据系统出力及外部条件对系统参数作初选,算出系统阻力;如果计算结果偏离经验数据,则需对管径、灰气比进行调整,重新计算,直至得到合理的数值,并据此确定最终系统参数。

Research on flow characteristics of positive dense phase pneumatic conveyance and system selection

Positive dense phase pneumatic conveyance is widely applied, but the calculation and parameter selection are rather complicated. Based on the analysis of current pneumatic conveyance mode and the influence of pipe length, velocity and ash-air quality ratio on pipe pressure, the conveyance characteristics of pipes were discussed, the cause of pipeline blocking was found out and the selection method for suspension velocity was given, providing guidance for energy-saving and consumption reduction in the design of positive dense phase pneumatic conveyance. In addition, the existing calculation concepts for pneumatic conveying system were induced, based on this, Cut-and-try Method was proposed for parameter selection i. e. selecting the preliminary system parameters according to system output and external conditions and calculating the system resistance;if the results deviate from experiential data, adjusting the pipe diameter and ash-air ratio for recalculation till the reasonable data were found;then the final system parameters can be determined.