| 方乐,刘雄军,谢启源.线芯电流预热对阻燃电缆引燃与向上自维持蔓延燃烧特性影响的实验研究[J].火灾科学,2025,34(1):7-17. |
| 线芯电流预热对阻燃电缆引燃与向上自维持蔓延燃烧特性影响的实验研究 |
| Experimental study on effects of electric current preheating on upward self-sustaining flame spread of flame-retardant cables |
| |
| 查看全文 查看/发表评论 下载PDF阅读器 |
| DOI：10.3969/j.issn.1004-5309.2025.01.02 |
| 基金项目:国家自然科学基金项目(52276139) |
|
| 中文关键词: 线芯电流预热 阻燃电缆 自维持火蔓延 |
| 英文关键词:Preheating of electric current Flame-retardant cable Self-sustaining flame spread |
| 摘要点击次数: 1625 |
| 全文下载次数: 50 |
| 中文摘要: |
| 阻燃电缆应用越来越广泛而其真实引燃与蔓延燃烧特性复杂。针对典型商业阻燃电缆(WDZA-BYJ450/750 V,额定电流25.0 A),开展了不同通电电流预热、标准喷射火不同作用时长条件下的引燃和竖直向上蔓延燃烧系列实验。结果表明,通电电流强度分别为12.5 A、25.0 A、37.5 A、50.0 A 和62.5 A时,电缆表面预热温度相对初始环境温度升高约5 ℃、18 ℃、36 ℃、74 ℃和140 ℃。通电电流预热作用下,阻燃电缆表面燃烧强度显著提高,炭化长度也随通电电流的增大而明显增大。此外,无电流工况下,阻燃电缆可形成自维持向上火蔓延的喷射火引燃时长区间为20 s~45 s,随着通电电流预热的增强,该时长区间呈下限值减小而上限值增大的趋势(如:电流为62.5 A时,时长区间为15 s~60 s)。结合电流预热后的竖直阻燃电缆表面温度演化曲线的计算结果表明,线芯电流对电缆提前引燃和竖直向上加速火蔓延具有显著的促进作用。 |
| 英文摘要: |
| Flame-retardant cables are increasingly widely used, yet their detailed ignition and burning characteristics are rarely known. This paper conducts a series of experiments on the ignition and vertical upward flame spread of a typical commercial flame-retardant cable (WDZA-BYJ 450/750 V, rated current 25.0 A) with the preheating of different electric currents by standard jet flames with different durations. The results show that the temperatures on the cable surface increase by about 5 ℃, 18 ℃, 36 ℃, 74 ℃ and 140 ℃ relatively for the currents of 12.5 A, 25.0 A, 37.5 A, 50.0 A and 62.5 A, respectively. Because of the preheating of electric current, both the burning intensity and carbonization length of the flame-retardant cable significantly increase with the increase of electrified current. Moreover, in the case of unpowered cable, a self-sustaining upward flame can be formed if the exposure time of standard jet fire is in the range of 20 s~45 s. With the increase of electric current, this duration range tends to decrease in the lower limit while increasing in the upper limit (e.g., at 62.5 A, the duration range is 15 s~60 s). Finally, the calculated results of the time-dependent surface temperatures on the surface of vertical flame-retardant cables indicate that the current significantly affects the earlier ignition and faster upward flame when electric currents are larger. |
| 关闭 |
|
|
|
