| The rapid development of railway industry has brought great convenience to people’s life, but in recent years, the frequent occurrence of railway locomotive fires has also imposed serious threats to the safety in railway operations. In order to solve the problems existing in the railway locomotive fire safety system, this paper explores the railway locomotive fire behaviors, such as the combustion characteristics, fire heat release rate and fire resistance. The aims are to study the railway locomotive fire safety issues, to optimize the fire alarm system and to improve the fire safety performance.In this paper, the combustion characteristics, fire heat release rate and structural fire resistance of railway locomotives are studied. The relationship between the ignition time, external radiation heat flux and critical incident heat flux of different materials is analyzed and studied. The HNF model of the material combustion was established according to the hazard assessment of the material, by combining the hazard index HI model, N-gas model and FED model. HNF model can be a good assessment and prediction of the dangers of toxic combustion production gases.In addition, according to the distribution, structure and function of the combustible materials in CKD0A diesel locomotive, the fire scenario setting is determined. Various situations and parts of the railway system after the fire are analyzed. At the same time, the development of railway locomotive fire is studied through field experiments, and the actual effect of railway locomotive fire prevention/monitoring system is tested.Secondly, in this paper, numerical simulation is used to study the fire development trend of diesel locomotive fire, so as to develop compound detection technology for diesel locomotive fire. Based on the special circumstances of railroad locomotives and the complexity of railway locomotive internal system, this paper chose two kinds of typical diesel locomotives, CKD0A and HXN5, to build the simulation scenarios. The study points include the characteristics of the early pyrolysis products of the railway locomotives, the flue gas migration characteristics at the early stage of the fire, the distribution of the concentration of the product components, the temperature increase characteristics of the flue gas; the possible effects of the different combustibles in the railway locomotives and fire growth characteristics and the development of fire spread.Then, in order to analyze the temperature distribution, smoke concentration, CO and other parameters in smoldering material combustion process, and also to further study the dust, oil mist and electromagnetism, locomotive fire detection and alarm system experiments were carried out in the small-scale experiments, the 6A laboratory and the 1:3 locomotive respectively. Combining with the growth characteristics and the fire spread of the railway locomotive fire, this paper studies the temperature field and composition concentration field distribution of railway locomotives under the condition of early railway locomotive fire. Considering the advantages and disadvantages of different fire detectors, the types and layout of fire detectors for railway locomotive fire are studied.Furthermore, this paper seeks to improve the fire detection algorithm and reduce the false alarm rate based on the difference of fire detection parameters between the railway locomotive fire and the daily operating environment. Based on the information fusion technology, the fire detection and alarm mechanism of the locomotive is optimized, and a new locomotive fire monitoring system is developed. The real vehicle test is carried out on the Datong HXD2 model locomotive.In the end, this paper combines locomotive fire simulation and experimental results and lots of locomotive operation data analysis, implements locomotive fire protection system design loading application. The fire loading scheme of HXD2 locomotive and HXN5 locomotive are also improved and tested. |
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