Flame Behavior and Thermal Propertoifes a Jet Flame with a HighInitial Discharging Velocity

为了研究高初速射流火焰的火焰行为和热性能，进行了一系列实验。为了研究火焰形成方向对火焰行为和热性能的影响，将实验数据与参考氢气射流火焰的火焰长度和温度数据进行了比较。实验条件不同，燃料释放时间和燃料质量流量也不同。对于初始速度较高的射流火焰高度，达到准稳态至少需要1秒，对于射流火焰周围的温度，达到准稳态至少需要3秒。火焰高度（火焰形成方向：垂直）和/或火焰长度（火焰形成方向：水平）取决于Q*2/5的范围，火焰高度和/或火焰长度不影响放热速率的范围可以除以RM的范围，RM表示气体释放动量与纯浮力扩散火焰产生的动量之比，而不考虑Q*的范围。沿射流火焰中轴线的温度与放热速率的变化保持相似。温度下降的起始点在离火源更远的位置，即放油喷嘴的出口。但一旦温度开始下降，温度下降的速度比McCaffrey关系更快。建立了沿射流火焰中心轴温度的经验公式，该公式可以预测射流火焰的形成方向。

In order to investigate flame behavior and thermal properties of the jet flame with comparatively high initial velocity, a series of experiments was carried out. The jet flame was made vertically in the present experiment, and to investigate the influence of the flame formation direction on the flame behavior and thermal properties, present experimental datum were compared with the datum of the flame length and temperature of hydrogen jet flame in reference. The fuel releasing time and the mass flow rate of fuel were varied as experimental conditions. At least one second is necessary to reach a quasi steady state for the height of the jet flame with comparatively high initial velocity, and at least three seconds is necessary for the temperature around the jet flame. The range that the flame height (flame formation direction: vertical) and/or flame length (flame formation direction: horizontal) depend on the Q*2/5 and the range that the flame height and/or flame length don't deped the heat rlease rate can be divided by the range of RM which implies the ratio of the gas release momentum to the momentum generated by a purely buoyant diffusion flame, regardless of the range of Q*. The temperature along the central axis of the jet flame maintains similarity with the change of the heat release rate. The starting point of the temperature decrease was moved further position from the fire source which was the outlet of the fuel releasing nozzle. But once the temperature decrease starts, the temperature decreased more rapid than McCaffrey's relation. The empirical formulae on the temperature along the central axis of the jet flame were developed which can predict regardless of the formation direction of the jet flame.