入口结构对高压管式反应器夹套内流动特性影响研究

Influence on Flow Characteristic in Annular Tube of High-pressure Tubular Reactor Under Inlet Structures

针对高压管式反应器夹套腐蚀泄漏失效问题,采用CFD方法,基于FLUENT平台研究了入口结构对夹套内脱盐水流动特性及腐蚀失效的影响。结果表明,采用夹套入口接管与夹套正交的结构,在入口与收缩环间产生了流动停滞区,造成脱盐水被过度加热,处于亚沸腾状态,同时脱盐水对反应管和夹套内侧壁产生直接冲刷。采用入口接管与夹套相切的结构,可以使脱盐水在夹套内形成旋流效应,有效地消除流动停滞区和高温区。实际使用证明,相切结构明显优于正交结构。

The numerical calculation based on FLUENT under CFD method was executed to study the reason why the jacket of the high-pressure tubular reactor was corroded and leaked and how flow characteristic and corrosion of the jacket were influenced by the inlet structure of the jacket. The results showed that there was an area where the velocity of water was so low that it nearly did not flow between water inlet tube and the plate ring, when the normal tube was used as inlet structure. So water in the area was heated up and sub-boiled. The extra-heat of the reac- tor water could not be effectively taken away and the high temperature area formed. On the other hand, the water in the inlet tube jet into the annular tube, which caused high shear stress in the joint between the inlet tube and the annular tube and in two sidewall of the annular tube near the inlet. So the erosion in these positions was increasingly enhanced. When the tangential tube was used as inlet structure, water flowed into the annular tube in tangential direction and produced rotational flow. The primary stagnant area turned into active. So the stagnant and superheat area was eliminated. Using of inlet structures in practice proved the tangential inlet structure to be superior to the normal inlet structure.