为有效防止工业生产中气体和液体(蒸气)爆炸事故的发生，需要获得相关物质的爆炸特性参数.对此，基于传统的20 L球形爆炸测试装置，对宏观静止和流动状态下甲烷和正庚烷的最大爆炸压力（pmax）、最大爆炸压力上升率（(dp/dt) max)和爆炸指数（KG）进行了测量和分析.结果表明：在2种状态下，甲烷的pmax和(dp/dt)max均随着体积分数的增加，先增大后减小，且2种参数均在体积分数为11%处同时达到峰值；在流动状态下，正庚烷的pmax和(dp/dt)max也呈现相似规律，并在体积分数为4%处达到峰值，即2种烷类的最佳爆炸体积分数分别约为11%和4%；此外，流动状态下 2种烷类在最佳爆炸体积分数处的pmax小幅提高5%~10%，相应的(dp/dt) max则显著提高到4~5 倍，导致爆炸释放能量与爆炸反应速率增大；2种物质在流动状态下的KG值增加到4~5倍，大幅增加爆炸的剧烈程度和危险性.

To effectively prevent gas and liquid (vapor) explosion accidents in industrial production, it is necessary to obtain explosion characteristics of relevant gases and liquids. Based on the traditional 20 L spherical explosion test apparatus, the maximum explosion pressure(pmax), the maximum explosion pressure rise rate((dp/dt)max) and the deflagration index (KG) of methane and n-heptane with different concentrations were measured and analyzed under quiescent and flowing conditions. The results show that the  pmax and (dp/dt)max values of methane are increased with latter decreasing and reach the peak values at 11%concentration under both conditions. The pmax and (dp/dt)max  values of n-heptane show the same rule under flowing conditions and reach the peak values at 4% concentration. The optimal explosive concentrations of two alkanes are about 11% and 4%, respectively. The pmax  values of two alkanes at optimal explosive concentrations are increased slightly by about 5% to 10% under flowing conditions, and the corresponding  (dp/dt)max values are significantly increased by about 4 to 5 times, which leads to large explosion energy release and high explosion reaction rate. The KG values are also increased by 4 to 5 times, resulting in high destructiveness and hazard of explosions.