Hydrogen can be released to the nuclear power plant containment atmosphere during a reactor core melt accident, and the potential hydrogen explosion need to be mitigated by all efforts. One of the current hydrogen management methods in pressurized water reactors (PWR) is to prevent detonation with slow combustion using ignitor as designed in AP1000. A HYdrogen MIddle scale Test facility (HYMIT) was setup to study the hydrogen behavior and mitigation efficiency of ignitor. The main component of HYMIT is a steel cylinder tank whose height is 4 m and diameter is 2 m, and the tank volume is about 12 m³. The mixed gas content, gas temperature and pressure, and arrival of flame can be measured with gas analyzer, thermocouple array, piezoelectric pressure sensors, and photodiode array. The current paper studied combustion behavior of hydrogen-air homogeneous mixture in various hydrogen volume ratio up to 10% at different ignition positions, the results showed that for tests with less than 10% hydrogen concentration the hydrogen consumption ratio increased when ignition location descending from top to bottom, and the maximum pressure and temperature increased accordingly, and for 10% hydrogen concentration tests the consumption ratio, the maximum pressure and temperature were not affected by the ignition location,. The apparent flame velocities were estimated with both photodiode sensors and thermal couples and they were in good agreement, the maximum upward apparent flame velocity measured was 2.27 m/s. A minimum actual radius was recommended to estimate the initial quasi-laminar flame velocity using pressure measurement.

在反应堆堆芯融化事故期间，氢气可以释放到核电站的安全壳大气中，需要通过所有努力来减轻潜在的氢气爆炸。压水堆（PWR）中当前的氢气管理方法之一是使用AP1000中设计的点火器来防止缓慢燃烧引起的爆炸。甲HY drogen MI ddle规模Ť EST设施（HYMIT）是设置来研究氢行为和点火器的缓解效率。HYMIT的主要组件是一个钢瓶罐，其高度为4 m，直径为2 m，罐容积约为12 m ³。可以使用气体分析仪，热电偶阵列，压电压力传感器和光电二极管阵列来测量混合气体含量，气体温度和压力以及火焰的到达。本文研究了氢-空气均质混合物在不同点火位置下氢气体积比高达10％的燃烧行为，结果表明，对于低于10％氢气浓度的测试，当点火位置从顶部下降时，氢气消耗率增加到底部，并且最大压力和温度相应增加，并且对于10％的氢浓度测试，消耗比，最大压力和温度不受点火位置的影响。用光电二极管传感器和热电偶估算了视在火焰的速度，它们吻合得很好，测得的最大向上视在火焰速度为2.27 m / s。建议使用最小实际半径以使用压力测量来估计初始准层火焰速度。