高速混床内树脂颗粒表层搅动性模拟研究

Simulation of agitation at resin particles layer surface in high-speed mixed bed

对自行设计的高速混床“多支管布水+多孔帽”布水结构(模型1)和传统“一次挡板+水帽”布水结构(模型2)树脂颗粒表层扰动进行了研究。通过对比模型1高速混床试验和模拟压差值证明了模拟方法的有效性。在此基础上,对2种布水结构在流速为140 m/h时的出水流速分布进行模拟。结果表明,模型1出水流速分布更为均匀,且最大流速明显小于模型2。针对树脂颗粒之间互相作用力复杂、难以通过仿真模拟树脂颗粒表层真实搅动状态的问题,采用试验法观测树脂颗粒表层搅动状态。结果表明,模型1树脂颗粒表层发生搅动临界流速位于80~100 m/h,同时通过模拟得出流速为80 m/h时树脂颗粒表层的水流分布情况,结合试验和模拟结果得出树脂颗粒表层扰动临界速度为0.05 m/s;对模型1流速为140 m/h时树脂颗粒表层的水流分布进行模拟,得出最大流速为0.075m/s,超临界速度面积占比为41.9%,且试验结果表明,流速为140 m/h时树脂颗粒表层稳定。因此,后续设计中当树脂颗粒表层最大流速不大于0.075 m/s,且超临界速度面积占比不大于40%时,可认为此时树脂颗粒表层稳定,满足要求。

The surface disturbance of resin particles in the self-designed high-speed mixed bed“multi-pipe water distribution+porous cap”water distribution structure(model 1)and the traditional“primary baffle+water cap”water distribution structure(model 2)were studied.The effectiveness of the simulation method is proved by comparing the model 1 high speed mixed bed test with the simulated differential pressure.On this basis,the outflow velocity distribution of the two water distribution structures was simulated at a flow rate of 140 m/h.The results showed that the outflow velocity distribution in Model 1 was more uniform,and the maximum velocity was significantly smaller than that in Model 2.In order to solve the problem that the interaction force between resin particles was complex and it was difficult to simulate the real agitation state of resin particles on the surface by simulation,the experimental method was used to observe the agitation state of resin particles on the surface.The results showed that in Model 1,the critical flow rate of resin particles on the surface was between 80 m/h and 100 m/h.At the same time,the flow distribution on the surface of 80 m/h resin particles was obtained by simulation,and the critical disturbance velocity on the surface of resin particles was 0.05 m/s based on the experimental and simulation results.By simulating the surface water flow distribution of resin particles at a flow rate of 140 m/h in model 1,it was concluded that the maximum flow rate of model 1 was 0.075 m/s,and the area of supercritical velocity accounted for 41.9%.The experimental results showed that the surface of resin particles at a flow rate of 140 m/h in model 1 was stable.Therefore,in the subsequent design,when the maximum velocity of resin particles on the surface was not more than 0.075 m/s and the proportion of supercritical velocity area was not more than 40%,it could be considered that the surface of resin particles was stable and met the requirements.