Simulation for effects of draft tube diameter on flow characteristics in a spouted bed using computational particle fluid dynamics (CPFD) method

doi:10.16085/j.issn.1000-6613.2017-0772

Abstract

Abstract: The spouted bed with draft tube is a kind of improved structure of spouted bed, which can improve the regularity and stability of spouting process by blocking the gas-solid contact between spray area and annulus. This paper carried out the numerical simulation for a 150mm diameter spouted bed using computational particle fluid dynamics (CPFD)method. The effects of draft tube diameter on flow characteristics was investigated from the dead zone of the annulus, particle velocity distribution and solid circulating rate. Results show that the draft tube reduced bed dead zone and solid circulating rate. For this spouted bed structure and operation parameters, only 40-60mm draft tube diameter can ensure the bed has a good spouting state, and 50-55mm draft tube is most appropriate. For a spouted bed with similar structure, the draft tube diameter should be selected as 1.25-1.375 times as the spray area diameter of spouting without draft tube.

Key words: spouted bed, numerical simulation, draft tube, granular flow, granular materials

摘要： 导向管喷动床是较为常见的一种喷动床改进床型，通过阻断喷动区与环隙区气固接触来提高颗粒循环的规律性与稳定性。本文采用计算颗粒流体力学（CPFD）方法对于直径150mm的柱锥式导向管喷动床进行了数值模拟研究，考察了导向管直径对于喷动床内颗粒流动特性的影响，从环隙区死区分布、颗粒速度分布、固体循环量等方面分析了具有不同直径导向管喷动床的运行状态。结果表明，加入导向管在减少床内死区的同时也降低了运行时的固体循环量，对于本次采用的喷动床结构尺寸与运行参数，只有在导向管直径为40～60mm时才能保证床内具有良好喷动状态，综合考虑各因素，选用直径50～55mm的导向管最为合适。对于具有类似结构与运行条件的柱锥喷动床，导向管直径可考虑选为无导向管运行时喷动区直径的1.2～1.375倍。

关键词: 喷动床, 数值模拟, 导向管, 颗粒流, 颗粒物料

CLC Number:

TQ051

ZHANG Lidong, WANG Zijia, LI Shaohua, WANG Qing, QIN Hong. Simulation for effects of draft tube diameter on flow characteristics in a spouted bed using computational particle fluid dynamics (CPFD) method[J]. Chemical Industry and Engineering Progress, 2018, 37(01): 14-22.

张立栋, 王子嘉, 李少华, 王擎, 秦宏. 导向管直径对喷动床流动特性影响的计算颗粒流体力学数值模拟[J]. 化工进展, 2018, 37(01): 14-22.

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