Study on the pre-ignition temperature variations of wire insulation under overload conditions in microgravity by the functional simulation method

Wang, Kai; Wang, Baorui; Kong, Wenjun; Liu, Fengshan

doi:10.1177/0734904113511947

Cited by 12 publications

(2 citation statements)

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“…Therefore, we proposed the overload heating as the internal heat source to study the early temperature rise characteristics and radiation characteristics of wire under overload current. The experiment was performed on board the SJ-8 satellite (Kong et al 2006;Kong et al 2008;Wang et al 2014). In the experiment, there is no external ignition source, and the wire fault is caused by its own overload heating by excessive current to simulate the effects of a short circuit.…”

Section: Introductionmentioning

confidence: 99%

Smoke Emission and Distribution Characteristics of Overloaded Wire Insulations under Microgravity

Zhuang

Kong

2022

Microgravity Sci. Technol.

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With the development of manned space technology, spacecraft safety and fire prevention have attracted more and more attention. Due to the disappearance of buoyancy in microgravity, the fire early monitoring, detection and alarm technologies designed based on ground experimental results are not suitable for spacecraft. It is necessary to develop fire early monitoring technology in microgravity. Smoke is an important early monitoring signal for fire prevention both in normal gravity and microgravity. Under microgravity, fire is mostly caused by overload or aging of wire insulations. In order to study the smoke emission characteristics of wire insulations under microgravity, we carried out the overload experiments of wire insulations on board the SJ-10 Chinese recoverable satellite. The smoke generation characteristics captured by laser extinction methods, and a large number of experimental data in the real microgravity environment were obtained for the first time. In this paper, the smoke volume fractions in the early and axisymmetric stages of smoke emission from the wire insulating layer are obtained by using the method of Abel transform and convolution, and the MATLAB algorithm program is compiled. In the later stage of smoke emission, it does not show axisymmetric distribution, but the laser extinction results can be used for obtaining the smoke emission trajectory. According to the results, two smoke emission modes in the early stage of ignition of wire insulation in microgravity are quantitatively analyzed. The effects of insulation thickness, overload current and insulation material on smoke emission are discussed.

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Section: Introductionmentioning

confidence: 99%

Smoke Emission and Distribution Characteristics of Overloaded Wire Insulations under Microgravity

Zhuang

Kong

2022

Microgravity Sci. Technol.

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“…Further on-ground studies in low pressure and narrow channel confirmed the validity of similarity theory to study the pre-ignition characteristics of wire insulations. 26,27 In drop tower, Fujita et al 28 reported the limited oxygen concentration of the PE insulation is much lower in microgravity. Guan et al 29 investigated the size and the morphology of smoke jetted from the fluorinated ethylene propylene (FEP) insulation layers before the occurrence of the flame spreading.…”

Section: Introductionmentioning

confidence: 99%

Smoke emission and temperature characteristics of the long-term overloaded wire in space

Xue

Kong

2019

Journal of Fire Sciences

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We developed an experimental payload to study the overloaded characteristics of wire insulations on board the China’s SJ-10 satellite. In 2-week microgravity experiments provided by the orbital flight, the smoke emissions of overloaded wire insulations were observed in space for the first time. Two smoke emission modes, namely the end smoke jet and the bubbling smoke jet, were identified with polyethylene insulations. The results showed that the geometry of the pyrolysis front dominated the direction and the range of the end smoke jet. The non-oxidative pyrolysis that occurred between the wire core and the insulation produced the high-temperature smoke and caused the bubbling smoke jet. The bubbling jet has a significant impact on the temperatures of adjacent wires, revealing an additional fire risk in microgravity. The effects of insulation thickness and excess current on the temperature rise were also discussed.

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Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures

Wang

Wei

et al. 2019

Fire and Materials

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SummaryMelt dripping of polymer insulation in electrical wires is impacted by some factors, such as ambient pressure and electric current. The motivation of this paper is to investigate and discuss the effect of these factors on melt dripping characteristics in the process of flame spread over electrical wire. The results show that the number of dripping times and dripping frequency generally increase with ambient pressure reduced. No dripping phenomenon occurs when the ambient pressure is below 40 kPa at any electric current or is above 70 kPa without electric current applied. There is a good parabolic correlation between the ambient pressure and dripping frequency. The equilibrium temperature of conductor resulted by electric current increases with electric current. A critical electric current found to divide the temperature rate into two regimes is about 8 A. The dripping period and dripping frequency depend on the electric current. The dripping frequency fits well with electric current using a power‐law function. The numerical data are consistent with the experimental data. Besides, the decrease in dripping frequency is greater with ambient pressure at reduced electric current, whereas at larger electric current, the electric current, rather than the ambient pressure, dominates the increased dripping frequency.

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Study on the pre-ignition temperature variations of wire insulation under overload conditions in microgravity by the functional simulation method

Cited by 12 publications

References 11 publications

Smoke Emission and Distribution Characteristics of Overloaded Wire Insulations under Microgravity

Smoke Emission and Distribution Characteristics of Overloaded Wire Insulations under Microgravity

Smoke emission and temperature characteristics of the long-term overloaded wire in space

Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures

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