连续进料多腔室流化床停留时间分布数值模拟

doi:10.11949/0438-1157.20251066

摘要/Abstract

摘要：

为揭示多腔室流化床反应器的流体动力学特性与颗粒停留时间分布（RTD）规律，优化其结构与操作参数，基于欧拉-欧拉双流体模型耦合组分输运方程，建立了连续进料多腔室鼓泡流化床的数值模型，对比研究了无挡板及不同挡板开孔高度、出口管高度、内置管束和固体流量条件下的多腔室流化床内气固两相流动特性、RTD及返混行为。结果表明，多腔室挡板流化床可有效抑制气泡尺寸，各腔室流体动力学行为高度一致；挡板结构使RTD趋近平推流，颗粒平均停留时间增加14.5%，方差由0.79降至0.58，以20 mm开孔高度为最优。降低床高使停留时间缩短45.2%，而埋管结构可进一步降低方差15.1%；固体流量降低延长停留时间，但亦加剧返混。本研究为钙循环热化学储能反应器的优化设计与放大运行提供了理论支撑。

关键词: 流化床, 流体动力学, 多腔室, 停留时间, 数值模拟

Abstract:

To reveal the hydrodynamic characteristics and particle residence time distribution (RTD) patterns of a multi-chamber fluidized bed reactor, and to optimize its structure and operational parameters, a numerical model of a continuously fed bubbling fluidized bed was developed using the Eulerian–Eulerian two-fluid model with species transport equations. Comparative simulations were carried out for baffle-free fluidized beds and multi-chamber beds under varying baffle opening heights, outlet tube heights, immersed tube bundle configurations, and solid feed rates. The gas–solid flow patterns, RTD, and back-mixing behavior were systematically evaluated. Results show that the multi-chamber baffled bed effectively suppresses bubble growth and promotes uniform hydrodynamics across chambers. Baffles shift the RTD toward plug flow, increasing the average residence time by 14.5% and reducing variance from 0.79 to 0.58. A baffle opening height of 20 mm delivered optimal performance. Reducing bed height shortened residence time by 45.2% but had limited mixing benefits, while adding immersed tubes further reduced variance by 15.1%. Decreasing the solid feed rate from 80 g/s to 60 g/s increased average residence time but intensified back-mixing. This study offers theoretical and practical insights for the design and scale-up of high-performance calcium looping reactors for thermochemical energy storage.

Key words: fluidized-bed, hydrodynamics, multi-chamber, residence time, numerical simulation

中图分类号:

TQ051.13

郭晓蝶, 周文静, 魏进家. 连续进料多腔室流化床停留时间分布数值模拟[J]. 化工学报, DOI: 10.11949/0438-1157.20251066.

Xiaodie GUO, Wenjing ZHOU, Jinjia WEI. Numerical simulation of residence time distribution in multi-chamber fluidized bed with continuous feeding[J]. CIESC Journal, DOI: 10.11949/0438-1157.20251066.

图/表 13

图1 几何结构示意图：(a)多腔室鼓泡流化床模型示意图；（b）单个腔室中埋管的位置参数

Fig.1 Schematic of geometric structure: (a) schematic of multi-chamber bubbling fluidized bed model; (b) position parameters of immersed tubes in a single chamber.

表1 物性参数及模型参数设置

Table 1 Physical parameters and model parameters setting

参数		值
气相	密度, kg·m^-3	0.38215
气相	黏度, Pa·s	4.0×10^-5
颗粒相	密度, kg·m^-3	2730
	黏度, Pa·s	1.798×10^-5
	粒径, mm	0.5
表观气速, m/s		0.4
最小流化风速, m/s		0.098
初始固体填充率		0.5
初始床层高度, m		0.29
气体边界条件		无滑移
固体边界条件		部分滑移
镜面反射系数		0.1
恢复系数		0.9
堆积极限		0.63
摩擦堆积极限		0.61
梯度离散		PISO
压强-速度耦合		Phase coupled SIMPLE
动量离散		Second-order upwind
体积分数离散		QUICK
时间步长, ms		0.5

图2 网格独立性测试：（a）固体质量随时间变化；（b）不同网格分辨率下的床层压降

Fig.2 Mesh independence test: (a) solid mass variation with time; (b) bed pressure drop at different mesh resolutions

图3 RTD模拟结果与实验结果的对比

Fig.3 Comparison of RTD simulation results with experimental results

图4 固体体积分数云图和颗粒速度矢量图瞬时分布：(a) 无挡板；(b) 80mm；(c) 50mm；(d) 20mm

Fig.4 Instantaneous distribution of solid volume fraction contour and particle velocity vector: (a) without baffle; (b) 80 mm; (c) 50 mm; (d) 20 mm

图5 时均固体体积分数和时均轴向颗粒速度

Fig.5 Time-averaged solid volume fraction and time-averaged axial particle velocity

图6 反应器各腔室压降对比

Fig.6 Comparison of pressure drop in each chamber of the reactor

图7 颗粒速度云图分布：(a)轴向速度 (b)径向速度

Fig.7 Particle velocity contour distribution: (a) axial velocity; (b) radial velocity

图8 有无挡板和挡板开孔高度对反应器出口（a）颗粒停留时间分布E（t）和（b）累积颗粒停留时间分布的影响F（t）

Fig.8 Effect of baffle presence and opening height on (a) the residence time distribution function, E(t), and (b) the cumulative residence time distribution function, F(t), at the reactor outlet.

图9 固体体积分数云图和颗粒速度矢量图瞬时分布：（a）H = 290 mm：（b）H = 220 mm；（c）H = 150 mm；（d）H = 150 mm（内置管束）

Fig.9 Instantaneous distribution of solid volume fraction contour and particle velocity vector: (a) H = 290 mm; (b) H = 220 mm; (c) H = 150 mm; (d) H = 150 mm (with tubes)

图10 各腔室出口RTD分布：（a）H = 290 mm；（b）H = 220 mm；（c）H = 150 mm；（d）H = 150 mm(含管束)

Fig.10 RTD distribution at the outlet of each chamber: (a) H = 290 mm; (b) H = 220 mm; (c) H = 150 mm; (d) H = 150 mm (with tubes)

图11 多腔室流化床反应器出口管颗粒停留时间分布和累积颗粒停留时间分布对比：(a) E（t）；(b) F（t）

Fig.11 Comparison of particle residence time distribution E(t) and cumulative particle residence time distribution F(t) at the outlet pipe of the multi-chamber fluidized bed reactor: (a) E(t); (b) F(t)

图12 不同固体流量对各个腔室的颗粒RTD分布的影响

Fig.12 Effect of different solid flow rates on particle RTD distribution in each chamber

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