<p>This paper experimentally investigates the ignition behavior of three types of foam insulation materials when exposed to liquid droplets generated from the flame spreading wires under varying currents from 0 to 50 A. The results indicate that the individual droplet mass produced during wire combustion increases with current intensity. The larger thickness of PE for Type III wire will generate the larger droplet mass. The dripping frequency also increases with the increasing current, which can be well predicted with the theoretical analysis. When droplets drip onto the foam insulation materials, the total mass of RPUF and RPUF + EG10 foams will decrease due to combustion, whereas the mass of EPS foam increases as droplets penetrate the material without ignition. On the other hand, the number of droplets required to penetrate and ignite the foam decreases as the current increases. And the critical dripping mass for igniting insulation materials is proposed, which increases with current. The total ignition time <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$t_{{{\text{ig}}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>t</mi> <mtext>ig</mtext> </msub> </math></EquationSource> </InlineEquation> is firstly divided into the dripping time of the critical mass <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$t_{{{\text{dr}}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>t</mi> <mtext>dr</mtext> </msub> </math></EquationSource> </InlineEquation> and after the ignition time of the foams <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$t_{{{\text{ig}},0}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>t</mi> <mrow> <mtext>ig</mtext> <mo>,</mo> <mn>0</mn> </mrow> </msub> </math></EquationSource> </InlineEquation>, which also increases with current. Finally, a heat transfer model is established to reveal the ignition times of insulation materials by dripping droplets. It is demonstrated that, the calculated ignition time <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$t_{{{\text{ig}}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>t</mi> <mtext>ig</mtext> </msub> </math></EquationSource> </InlineEquation> shows a good agreement with the experimental value.</p>

Thermal analysis of drippings of charged wire on ignition and interaction behaviors with typical insulation materials

期刊论文
发表日期：

2026年6月29日

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Xinjie Huang,
Peng Xu,
Zhipeng Yin,
Hailong Ding

摘要

This paper experimentally investigates the ignition behavior of three types of foam insulation materials when exposed to liquid droplets generated from the flame spreading wires under varying currents from 0 to 50 A. The results indicate that the individual droplet mass produced during wire combustion increases with current intensity. The larger thickness of PE for Type III wire will generate the larger droplet mass. The dripping frequency also increases with the increasing current, which can be well predicted with the theoretical analysis. When droplets drip onto the foam insulation materials, the total mass of RPUF and RPUF + EG10 foams will decrease due to combustion, whereas the mass of EPS foam increases as droplets penetrate the material without ignition. On the other hand, the number of droplets required to penetrate and ignite the foam decreases as the current increases. And the critical dripping mass for igniting insulation materials is proposed, which increases with current. The total ignition time $t_{{{\text{ig}}}}$ $t_{ig}$ is firstly divided into the dripping time of the critical mass $t_{{{\text{dr}}}}$ $t_{dr}$ and after the ignition time of the foams $t_{{{\text{ig}},0}}$ $t_{ig, 0}$ , which also increases with current. Finally, a heat transfer model is established to reveal the ignition times of insulation materials by dripping droplets. It is demonstrated that, the calculated ignition time $t_{{{\text{ig}}}}$ $t_{ig}$ shows a good agreement with the experimental value.