管路内高温高压气液两相流动特性

Characteristics of gas-liquid two-phase flow at high temperature and high pressure in the pipeline

管路结构设计与优化对提高工质输运效率具有重要意义。针对亚/超临界水氧化工艺中涉及的气液两相流动过程进行了三维非稳态数值模拟。结果表明,管路内温度沿流动方向逐渐降低,气含率逐渐升高;不同结构管路内压力分布呈显著差别。水平直管内压降随管径增大而降低,但当管径达到0.016 m时,压降变化不再显著;水平渐扩管内压降随渐扩段管路长度的增加先降低后升高,当渐扩管路长度为0.1 m时,工质输运效率最高;水平渐缩管内压降随渐缩段管路长度的增加先降低后升高再降低,表明通过对渐缩管路长度的合理选取可以实现快速降压的同时降低阻力损失。

The design and optimization of pipeline system is of great significance to improve the transport efficiency of working medium.The three-dimensional unsteady numerical simulation of gas-liquid two-phase flow in sub/supercritical water oxidation process was performed.The results showed that the temperature decreased and the gas holdup increased gradually along the flow direction.Pressure distribution in pipeline with different structures was significantly different,and the pressure drop in the horizontal straight pipeline decreased with the increasing of its diameter.The pressure drop fluctuation was no longer significant when the pipe diameter was greater than 0.016 m.The pressure drop in the horizontal diffuser pipeline first decreased and then increased with the increasing of the length of the horizontal diffuser.Especially the transport efficiency of the working medium was the highest when the diffuser length was 0.1 m.The pressure drop in the horizontal tapered pipeline first decreased,then increased and then decreased with the increasing the length of horizontal tapered pipeline,which shows that both the decrement of pressure and the reduction of resistance loss could be achieved by selecting the length of the horizontal shrinking pipeline reasonably.