高压天然气场站水平喷射火焰危害评估方法

Assessment Method of Horizontal Jet Flame Hazard of High Pressure Natural Gas Station

水平喷射型火灾是高压天然气场站最典型且危害性最大的火灾事故类型,为避免或减少其对周围人员、设备设施等造成的严重影响,开展了场站水平喷射火焰危害性评估方法的研究。首先,在以往相关理论分析和试验研究基础上,以水平倒置圆锥台形状去近似表征水平喷射火焰形貌,并给出火焰轮廓尺寸参数的解析表达式;然后,基于固体火焰模型采用模型等效变换的方式,建立火焰热辐射通量计算模型;最后,提出以热毁伤阈值为基准的目标受火焰热辐射伤害情况判定方法。应用与分析表明:火焰形貌尺寸会随着孔口泄漏率、压力、温度等泄漏参数的变化而变化,站内安全联动装置可在短时间内有效降低火焰热辐射通量;火焰热辐射伤害程度各等级间的变化或同一伤害级别下伤害百分数的陡变,均发生在较短距离范围内。研究成果可对水平喷射火焰的热毁伤半径和毁伤区域面积进行有效预测,有助于高压天然气场站事故风险的定量化评估和事故应急处置预案的制定。

Horizontal jet flame is the most representative and dangerous fire accident at high pressure gas station. In order to prevent or decrease its major threats to people and equipment around,this paper focuses on hazard assessment method of horizontal jet flame. First,based on the previous theoretical and experimental researches,the shape of horizontal jet flame is approximately described by a horizontal and inverted frustum; and calculating formulas for basic geometric parameters of the flame are presented. Then,equivalent transformation method is introduced,and thermal radiation flux model of jet flame is built based on solid flame model. Finally,the methods for assessing the injury extent are provided according to thermal damage threshold values of the targets. Research and application show that the sizes of horizontal jet flame change with the leakage parameters such as leakage rate,leakage pressure and leakage temperature. Flame thermal radiation flux could be reduced effectively in a short time with the help of safety interlocks.Moreover,the thermal damage level or damage percentage at the same level changes sharply within a very short distance. The research results presented could provide an effective prediction for thermal damage radius and damage area of horizontal jet flame. And it would be helpful for quantitative risk assessment and emergency response plan of high pressure gas station accident.