荷电乙醇-生物柴油液滴在燃烧过程中的破碎特性研究

doi:10.11949/0438-1157.20251057

摘要/Abstract

摘要：

搭建了荷电燃料液滴燃烧实验装置，通过可视化手段研究荷电乙醇-生物柴油液滴在燃烧过程中的破碎特性。结果表明，荷电乙醇-生物柴油液滴的燃烧过程由热膨胀阶段、气泡发展阶段、电致变形阶段和准稳态阶段组成，存在气泡发展和锥射流引起的液滴破碎模式。对于气泡发展引起的液滴破碎，液滴带电会增大E10（10vol%乙醇+90vol%生物柴油）液滴的破碎延迟期，减小E30（30vol%乙醇+70vol%生物柴油）液滴的破碎延迟期，基本不改变E50（50vol%乙醇+50vol%生物柴油）液滴的破碎延迟期；除了3 kV工况，液滴破碎强度基本随着电压增大而减小；液滴带电会减小E10液滴的子液滴尺寸，而E30和E50液滴的子液滴尺寸与电压间的规律不明显。锥射流产生的子液滴尺寸小于气泡发展产生的子液滴尺寸。

关键词: 生物柴油, 乙醇, 多相流, 荷电液滴, 液滴破碎, 液滴燃烧

Abstract:

An experimental setup for charged fuel droplet combustion is constructed. Visualization techniques are employed to examine the breakup characteristics of charged ethanol-biodiesel droplets during combustion. The results indicate that the combustion process of charged ethanol-biodiesel droplets consists of four stages: thermal expansion, bubble development, electrically-induced deformation, and quasi-steady state. Two droplet breakup modes are observed, induced by bubble development and cone jet, respectively. For bubble-induced breakup, droplet charging prolongs the breakup delay of E10 (10vol% ethanol + 90vol% biodiesel) droplets, shortens that of E30 (30vol% ethanol + 70vol% biodiesel) droplets, and has negligible effect on that of E50 (50vol% ethanol + 50vol% biodiesel) droplets. Except for 3 kV, the breakup intensity almost decreases with increasing voltage.

Key words: biodiesel, ethanol, multiphase flow, charged droplet, droplet breakup, droplet combustion

中图分类号:

左磊, 王军锋, 王道睿. 荷电乙醇-生物柴油液滴在燃烧过程中的破碎特性研究[J]. 化工学报, DOI: 10.11949/0438-1157.20251057.

Lei ZUO, Junfeng WANG, Daorui WANG. Study on breakup characteristics of charged ethanol-biodiesel droplets in combustion[J]. CIESC Journal, DOI: 10.11949/0438-1157.20251057.

图/表 11

图1 荷电燃料液滴燃烧实验装置

Fig. 1 Experimental setup of charged fuel droplet combustion

表1 乙醇-生物柴油掺混燃料的配制方案及物性参数

Table 1 Preparation schemes and physical properties of ethanol-biodiesel fuel blends

燃料标识	配制方案	物性参数
燃料标识	配制方案	密度/ (kg/m³)	表面张力/ (N/m)	动力黏度/ mPa∙s	沸点/ ℃	介电常数	电导率/ (S/m)
E10	10vol%乙醇+90vol%生物柴油	862	0.033	4.64	305	4.88	5.0 × 10^-6
E30	30vol%乙醇+70vol%生物柴油	847	0.030	3.82	254	9.19	1.5 × 10^-5
E50	50vol%乙醇+50vol%生物柴油	831	0.028	3.01	204	13.51	2.5 × 10^-5

图2 无电场作用下燃烧液滴的形态演变

Fig. 2 Morphology evolutions of burning droplets without the electric field

图3 电压为3 kV工况下燃烧E10液滴的特殊形态变化

Fig. 3 Special morphology evolutions of burning E10 droplets at the voltage of 3 kV

图4 荷电E10液滴在不同电压下的归一化平方直径及不稳定性参数曲线

Fig. 4 Curves of normalized squared diameter and instability parameter for charged E10 droplets at various voltages

图5 荷电E30液滴在不同电压下的归一化平方直径及不稳定性参数曲线

Fig. 5 Curves of normalized squared diameter and instability parameter for charged E30 droplets at various voltages

图6 荷电E50液滴在不同电压下的归一化平方直径及不稳定性参数曲线

Fig. 6 Curves of normalized squared diameter and instability parameter for charged E50 droplets at various voltages

图7 不同电压下荷电掺混燃料液滴的破碎延迟期

Fig. 7 Breakup delays of charged blend droplets at various voltages

图8 不同电压下荷电掺混燃料液滴的最大破碎强度

Fig. 8 Maximum breakup intensities of charged blend droplets at various voltages

图9 不同电压下荷电掺混燃料液滴的累计破碎强度

Fig. 9 Accumulative breakup intensities of charged blend droplets at various voltages

图10 不同电压下气泡发展和锥射流生成的子液滴索特平均直径

Fig. 10 Sauter mean diameters of secondary droplets released from bubble development and cone jet at various voltages

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