Experimental study on geometric characteristics of transformer oil jet fire under external heat source

ABSTRACT

The transformer oil jet fire accidents caused by the failure in the substation may cause significant economic losses. In this study, the geometric characteristics of transformer oil jet fire are studied by conducting experiments with different variable conditions. In this regard, CCD images and infrared images of jet flame are tested and analyzed under different diameter nozzles and different diameter containers. The obtained results show that the temperature boundary of jet flame varies in the range of 600 K ~ 700 K. The flame geometry can be approximated as a cylinder. Moreover, it is found that the heat release rate is a function of the flame height to the power of 2/5. When the Froude number is 1.5 × 10⁶, the flame governing mechanism from the buoyancy main control to the momentum main control. Flame width increases significantly as the heat release rate increases. The heat release rate is a function of the flame width to the power of 1/3. Furthermore, the flame volume is related to the 0.85 power of the heat release rate. The obtained results, are of great significance to improve the analysis capability of jet fire hazard, and prevent the control ability of transformer oil jet fire accidents in substations.

KEYWORDS:

• Jet fire
• flame boundary
• flame shape
• flame height
• flame width
• flame volume

Acknowledgments

This work is supported by the Science and Technology Project of the State Grid Corporation of China (8000-201918445A-0-0-00).

Disclosure statement

The authors declare no competing financial interest.

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Additional information

Funding

This work was supported by the State Grid Corporation of China [8000-201918445A-0-0-00].