基于图像法的环雾状流液滴参数测量与分析

doi:10.16085/j.issn.1000-6613.2021-1388

摘要/Abstract

摘要：

环雾状流广泛存在于石油化工领域，其内部流场测量具有重要意义。本文结合光学图像法和高速摄影技术对撞针式喷嘴的雾化特性进行了测量分析，以此为基础对基于雾化混合的环雾状流中夹带液滴特性开展了实验研究。利用高速摄影技术对喷雾进行可视化，采用单帧单曝光法对液滴尺寸和速度信息进行提取。研究发现，液滴速度随轴向距离增大呈衰减趋势，且相同轴向距离（约在径向位置10mm处）条件下，速度达到峰值；液滴索泰尔平均直径（SMD）随喷嘴孔径d₀的增大而增大，并与液相质量流量m_l和喷嘴上下游压差?p均呈负相关；另外，在环雾状流环境中，相同气压条件下液滴SMD随气相体积流量Q_g增大而减小，而相同气相体积流量条件下SMD随气压p_g增大而增大。基于实验测量结果，以气相韦伯数We_g和液相雷诺数Re_l为主影响参数，引入相间滑移和压力系数建立了基于量纲分析的环雾状流液滴SMD预测模型，平均绝对百分比误差MAPE为11.4672%。

关键词: 环雾状流, 成像分析, 颗粒测量, 液滴特征, 雾化特性

Abstract:

Annular mist flow is a kind of flow pattern widely existing in the field of petrochemical industry, and the measurement of its internal flow field measurement is of great significance. Combined with optical image method and high-speed photography technology, the atomization characteristics of the impaction-pin nozzle were measured. On this basis, the characteristics of the entrainment droplets in the Annular mist flow based on atomization mixing were studied. The spray morphology was visualized by high-speed photography, and the morphological changes were described visually. The single-frame single-exposure method was used to extract the distributions of droplet size and velocity. It was found that the droplet velocity decreases with the increase of the axial distance, and the droplet velocity reaches a peak at about 10mm in the radial position at the same axial distance. The results also showed that the Sauter mean diameter (SMD) increased with the increase of nozzle aperture, and was negatively correlated with the mass flow rate of liquid phase and the pressure drop. In addition, under the same gas pressure condition, SMD decreased with the increase of gas flow rate, while it increased with the increase of gas pressure at the same gas flow rate. Finally, the dimensional analysis based SMD prediction model of annular mist flow droplets was established by introducing the interphase slip and pressure coefficient, with gas Weber number and liquid Reynolds number as the main influencing parameters, and the MAPE is 11.4672%.

Key words: annular mist flow, imaging method analysis, particle measurement, droplet size and velocity, atomization

中图分类号:

TP212.9

丁红兵, 刘茜茜, 李金霞, 孙宏军, 梁真馨. 基于图像法的环雾状流液滴参数测量与分析[J]. 化工进展, 2021, 40(12): 6460-6468.

DING Hongbing, LIU Xixi, LI Jinxia, SUN Hongjun, LIANG Zhenxin. Measurement and analysis of droplet parameters in annular mist flow based on image method[J]. Chemical Industry and Engineering Progress, 2021, 40(12): 6460-6468.

图/表 15

图1 雾化装置结构与测量位置坐标

表1 喷嘴结构参数

喷嘴型号	孔径d₀/mm	A/mm	B/mm
PJ1	0.152	19.1	11.1
PJ2	0.203
PJ3	0.254

图2 喷雾测量实验系统

图3 环雾状流液滴测量实验系统

表2 环雾状流夹带液滴测量实验工况点

气路压力 /kPa	气路流量 /m³·h^-1	喷嘴型号	编号	液相质量流量 /kg·h^-1
150，200，250，300，350	12，15，18，21，24	PJ1	1	1.39
			2	2.30
			3	2.78
			4	3.29
			5	3.56
			6	3.75
		PJ2	1	1.65
			2	3.35
			3	5.11
			4	6.66
			5	8.01
			6	9.25
		PJ3	1	7.19
			2	8.64
			3	10.54
			4	12.06
			5	13.56
			6	15.13

表3 图像采集组件参数

组件	参数	指标
CCD相机	分辨率	1280×1024
	像元大小	3.45μm×3.45μm
远心镜头	工作距离	9.2~12cm
	放大倍率	0.5~4.5
光源	波长	532nm
频闪控制器	功率	50W
高速相机	最大分辨率	1280×1024
	最高拍摄速度	200000帧/s
	像元大小	10μm×10μm

图4 液滴特征计算模型

图5 0.9MPa喷射压力下喷雾形态变化

图6 喷雾液滴速度分布

图7 喷雾液滴速度分布拟合曲面图

图8 喷雾液滴粒径分布

图9 液滴SMD随液相工况变化趋势

图10 夹带液滴SMD在相同气相压力、不同气相流量条件下随液相质量流量的变化趋势

图11 夹带液滴SMD在相同气相流量、不同气相压力下随液相质量流量的变化趋势

图12 环雾状流液滴SMD模型预测效果

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