多射流锥形对撞流气流床流场特性实验及模拟研究

Characteristics of the Flow-Field Experiments and the Simulation Studies of the Multi Conical Nozzle Impinging Stream

为了考察多射流锥形对撞煤加氢气流床内的冷态流场情况,以3 t/d的热态煤加氢气化炉为依据建立了气流床冷模装置。使用三维动态颗粒分析仪(3D-PDA)对气流床内的速度场进行了测量,同时使用Fluent软件,采用κ-ε模型对气流床内的流动情况进行了模拟研究,模拟结果与实验结果能较好地吻合。结果显示:多射流锥形对撞气流床内的流体流动分为对撞区、射流区、回流区和管流区,在考察范围内,随着进气速度的增加,回流区的体积占比先增大后减小;随中心喷嘴携带气速度的增加,射流区速度增大,且较进气速度的影响更为敏感;适当增加进气角度,则会降低射流区速度,增大回流区体积。

In order to investigate the cold flow field on the multi nozzle impinging coal hydrogenationentrained flow bed, the cold model of a stream bed was established based on the 3 t/d thermal coalhydrogenation gasifier. The three-dimensional particle dynamic analyzer (3D-PDA) was used to measure thevelocity of the fluid in the model and the flow behaviors were simulated and analyzed using Fluent softwareand κ-ε dual equation model. It was found that the simulations are well consistent with the experimentalresults and the flow field can be catalogued into four zones: impinging stream, jet stream, recirculationstream and tube zone. With the increase of the gas inlet velocity, the volume percent of the recirculationstream zone increased and then followed by the decrease within the scope of the study. The rate of the jetstream zone increased with the increase of central nozzle carrying gas velocity, and its influence showedmore sensitive than that of the intake velocity; with appropriately increase of the intake angle, the velocity ofthe jet stream zone would be reduced and the volume of the recirculation stream zone increased.