新型湿法除尘系统内气液两相流动的数值模拟

doi:10.16085/j.issn.1000-6613.2019-1879

摘要/Abstract

摘要：

结合湿法除尘及挡板绕流技术，本文设计开发了一种带有挡板结构的新型湿法除尘系统。为探究该系统内挡板结构诱导产生的涡旋流动特性及其内部离散相运动规律，基于计算流体力学（CFD）方法，文章选用重整规划群（RNG）k-ε湍流模型数值对比了不同挡板参数下的涡旋结构、速度分布及压降情况等气相流场特性。同时利用离散相模型（DPM）分析了不同工况下喷淋液滴的运动轨迹、逃逸率及驻留时间表现。结果表明，集尘区内弓形挡板的设置可诱导产生涡旋流动，不仅能够抑制低速“流动死区”，同时还可不同程度改善喷淋液滴逃逸情况、有效延长其在装置内的驻留时间。综合考虑气相入口速度v、挡板安放角θ及喷淋液滴粒径D_p的影响，文章推导获得了液滴逃逸率的计算公式，可较为准确地预测喷淋液滴的运动情况。

关键词: 湿法除尘, 挡板绕流, 气液两相流, 离散相模型, 液滴, 逃逸率

Abstract:

A novel dedusting system was proposed by combining wet dust removal with baffle flow technologies. In order to investigate the characteristics of vortex flow induced by arc baffles and the motion of internal discrete phase in the new designed system, renormalization group (RNG) k-ε turbulence model was used to numerically compare the characteristics of gas flow field such as vortex structure, velocity distribution and pressure drop under different operation parameters by means of computational fluid dynamics (CFD) method. Meanwhile, discrete phase model (DPM) was applied for the study on the trajectory, escape rate and residence time in the dust collecting area. The results showed that the flexible baffles in dedusting system could bring vortex flow with various structures which effectively reduced the dead zone with low speed. When it came to spray droplets, it was found that the vortex improved the escape phenomenon and prolonged the residence time. The mathematic model of escape rate was established for predicting the movement of spray droplets in actual engineering by considering the effect of air inlet velocity, baffle placement angle and droplet size.

Key words: wet dedusting, flow around baffles, air-liquid flow, discrete phase model, droplet, escape rate

中图分类号:

O359⁺.1

许浩洁, 王军锋, 王东保, 张伟, 姚江. 新型湿法除尘系统内气液两相流动的数值模拟[J]. 化工进展, 2020, 39(9): 3590-3599.

Haojie XU, Junfeng WANG, Dongbao WANG, Wei ZHANG, Jiang YAO. Numerical simulation of gas-liquid flow in a novel wet dedusting system[J]. Chemical Industry and Engineering Progress, 2020, 39(9): 3590-3599.

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