核电厂封闭空间横向多层电缆燃烧纵向温度分布特征研究

Investigation on Vertical Temperature Profile Generated by Fire on Horizontal Multi-Layer Cable Tray in Closed Compartment of Nuclear Power Plant

针对核电厂横向多层电缆火灾危害性,研究封闭空间内电缆燃烧产生的室内温度分布特征及热烟气层温度预测模型。基于2种典型的电缆布置,在封闭空间进行了横向3层电缆燃烧实验。实验研究结果表明,横向多层电缆燃烧产生的热烟气层温度存在明显的分层现象。基于室内中心纵向温度分布,可将室内电缆燃烧产生的热环境分为底层冷空气层、中层热烟气层和顶层顶棚射流层。采用封闭空间内非稳态温度预测模型,对横向多层电缆桥架电缆火灾的热烟气层温度进行预测。通过比较模型预测结果和热烟气层温度实验测量值可以得到:该模型可以精确地预测封闭空间内热烟气层温度的最大值,相对误差小于1%;由于模型低估了火灾衰减阶段的温度发展,导致该模型预测整个温度发展的全局误差在16.3%~27.8%之间。

Focusing on the fire risk of the horizontal multi-layer cable tray in a nuclear power plant,the characteristics of the smoke layer temperature profile generated by the fire on the multi-layer cable tray in a closed compartment and the prediction model for the smoke layer temperature were investigated.Fire experiments of a three-layer cable tray with two typical cable arrangements were conducted in a closed compartment.The experimental results showed that the stratification of vertical smoke layer temperature was evident.Based on the vertical temperature profile in the compartment center,the thermal environment resulted from the fire can be classified as top ceiling jet layer,middle smoke layer,and lower cool air layer.The unsteady-state temperature prediction model in a closed compartment was used to predict the smoke layer temperature resulted from the fire on the horizontal multi-layer cable tray.The comparison of the predicted results with the experimental temperature for the smoke layer showed that this model can accurately predict the maximum temperature of the smoke layer,with relative error less than1%.the prediction model underestimated the temperature generated by the decay stage of the cable tray fire,and thus the global error is within 16.3%and 27.8%.