气固分离与排气一体机减阻的CFD数值仿真

发布时间：2018-06-02 01:18

本文选题：气固分离 + 离心叶轮　；参考：《华中科技大学》2015年硕士论文

【摘要】：气固离心分离与排气一体机(简称一体机)是以解决小颗粒分离问题的分离装置,其核心思想是将离心叶轮内置旋风分离器中,利用离心叶轮旋转产生的强大离心力对颗粒进行分离,自从被提出以来已有多届师兄对其进行了相关实验、理论分析和数值计算的研究工作。本文主要是利用CFD数值计算的手段,探索如何降低一体机的压降问题,全文可以得出以下结论:(1)采取RSM模型可以有效模拟旋风分离器的平均流场和压降,但会在一定程度上低估湍流脉动,进而会过高估计小颗粒的分离效率,但是其计算的较大颗粒的分析效率与实验值符合较好。采取Muschelknautz模型计算的分离效率具备一定准确性,在粒径较大时符合较好,而粒径较小时会低估其分离效率。(2)在同筒径和同流量的情况下,一体机相对于旋风分离器,流场特征没有发生明显变化,切向速度分布符合“组合兰金涡”特点,但切向速度增幅明显,分离效率也远大于旋风分离器。随着切向速度的增加,一体机的压降也显著增加,并且不能实现离心叶轮使一体机整机全压得到提升的设计初衷。(3)通过布置静止导叶的减阻方式,相对于直筒段的延长而言,前者减阻效果更加明显,同时没有较大地影响到切割粒径,而后者随着直筒段长度的延伸,切割粒径增加较大。但是对于较大颗粒的分离而言,延长直筒段长度的方式对此几乎没有影响,而加入静止导叶后则有明显降幅。在布置静止导叶后,一体机的湍流脉动得到了削弱,并有益于小颗粒的分离。
[Abstract]:The gas-solid centrifugal separation and exhaust integrated machine is a separation device to solve the problem of small particle separation. Its core idea is to integrate the centrifugal impeller into the cyclone separator. Since it was put forward, many experiments, theoretical analysis and numerical calculation have been carried out on the separation of particles by using the strong centrifugal force produced by centrifugal impeller rotation. In this paper, we mainly use the method of CFD numerical calculation to explore how to reduce the pressure drop of an integrated machine. The following conclusion can be drawn in this paper: (1) adopting RSM model can effectively simulate the average flow field and pressure drop of cyclone separator. However, the turbulence pulsation will be underestimated to a certain extent, and the separation efficiency of small particles will be overestimated, but the analytical efficiency of the larger particles calculated is in good agreement with the experimental values. The separation efficiency calculated by the Muschelknautz model has some accuracy and is in good agreement with the larger particle size, while the separation efficiency is underestimated when the particle size is small. (2) in the case of the same tube diameter and the same flow rate, the integrator is relative to the cyclone separator. The tangential velocity distribution accords with the characteristics of the combined orchid vortex, but the tangential velocity increases obviously, and the separation efficiency is much higher than that of the cyclone separator. With the increase of tangential speed, the pressure drop of the integrated machine also increases significantly, and the original design intention of the centrifugal impeller to enhance the whole machine's full pressure cannot be realized. (3) by arranging the static guide vane to reduce the drag, compared with the extension of the straight cylinder section, The drag reduction effect of the former is more obvious, and the cutting particle size is not affected greatly, while the latter increases greatly with the extension of the length of the straight cylinder. However, for the separation of larger particles, the way of lengthening the length of the straight tube has little effect on this, but there is a significant decrease after adding the static guide vane. After the stationary guide vane is arranged, the turbulence pulsation of the integrated machine is weakened and is beneficial to the separation of small particles.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.8

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