Abstract:

To study the influence of the initial fuel temperature of the transformer oil on the combustion characteristics, an oil pool fire combustion test platform was set up, and pool fire experiments with different initial fuel temperatures and different oil pool diameters were conducted. The whole burning process, burning rate and boiling layer thickness were measured and discussed with the variation of initial fuel temperature. The results show that the whole burning process can be divided into three stages: (1) initial development stage; (2) steady burning stage; (3) extinguishment. The burning rate shows an increasing trend with the increase of initial fuel temperature at the initial development stage. This is because the heat used to increase the fuel temperature will decrease with the increase of initial temperature. At the steady burning stage, although the burning rate will increase with the initial fuel temperature increasing, the increasing rate is slow and can be nearly neglected. In the experiments, the burning rate is increasing obviously with the increase of burning size. In addition, the boiling layer thickness is around 2.17 mm, independent of the initial fuel temperature at the steady burning, except the tests with a diameter of 20 cm. Therefore, it is necessary to improve the fire extinguishing efficiency to respond the initial fire development and build some barriers to avoid the leakage fuel spread.

Key words: transformer oil, initial fuel temperature, burning process, burning rate, boiling layer thickness

摘要：

为了研究变压器油初始油温对燃烧特性的影响，搭建了油池火燃烧实验平台，开展了不同初始油温及不同油池直径的池火实验，系统地分析了初始油温对油池火灾发展规律的影响，具体探讨了燃烧发展阶段、燃烧速率以及沸腾层厚度等参数随初始油温的变化规律。结果表明，变压器油池火的整个发展过程可分为：初始发展阶段、稳定燃烧阶段和火焰熄灭阶段。对于初始发展阶段，随着初始油温的升高，燃烧速率会不断增加，这主要是由于初始油温的升高降低了用于加热油品的热量；对于稳定燃烧阶段，燃烧速率会随着初始油温的升高而增加，但增幅较小。实验尺度范围内，前两个阶段的燃烧速率都会随着燃烧尺度的增加而显著增加。对于稳定燃烧阶段，除了直径20 cm的油池外，变压器油的沸腾层厚度接近2.17 mm，与初始油温无关。因此，在变电站消防设计中，应提高变压器火灾发展初期的灭火效率；同时，采用相应的阻隔措施避免泄漏油品的扩散蔓延。

关键词: 变压器油, 初始油温, 燃烧阶段, 燃烧速率, 沸腾层厚度