低压(真空)流体状态下的管径计算

在磷酸、磷肥装置的闪蒸过程中，管道中的气体均属于低压流体。在低压状态(或真空状态)下，物料分子间间距加大，分子间碰撞明显减少。其管道直径的计算仅凭工程经验进行简单估算，其结果往往不令人满意。本文就这个问题进行了分析，以找出在低压状态(或真空状态)下计算管径的方法。

The pipe diameter's calculation in low pressure (or vacuum) fluid

In flash evaporation process of phosphoric acid, phosphoric fertilizer equipment, air in the piping all belongs to the low-pressure fluid. In the low-pressure (or vacuum) state, material molecule's gap is enlarged, the hits between molecules obviously decrease. but calculation of the pipe diameter is only simple estimated relying on the engineering experience. the result can't be usually satisfied. This thesis analyzes about it, then finds out a method of calculating pipe diameter in the low-pressure ( or vacuum) stae.