在定容燃烧弹内生成不同频段湍流特性的方法研究

Method to Realize Turbulent Characteristics of Different Frequency Band in a Constant Volume Combustion Bomb

利用孔板平动法生成湍流 ,通过调节平板孔径的大小和驱动电机的转速来达到在定容燃烧弹内生成不同频段湍流特性的目的 .运用小波包分析法对容弹内气流速度进行了时 频分析 .结果表明 ,容弹内部存在极强的循环平均流 ,湍流主要处于 4 0 0～ 16 0 0Hz的频率段 ,它的能量衰减期一般不超过 6 0ms .同时 ,也得出了容弹内湍流的产生、发展与平板孔径和电机转速之间的关系 .

Turbulent characteristics of different frequency band in constant volume combustion bomb can be realized by changing the structure of the perforated plate and the velocity of driving motor. Using the wavelet packet analysis of the air velocity in the bomb, not only the turbulence can be separated from the in cycle mean velocity, but also the relationships of the turbulent generation and deve lopment with the diameter of bores and motor's rotating speed have been obtained. Results show that turbulent energies are mainly centralized in the frequency band form 400 Hz to 1 600 Hz, and turbulence attenuates very quickly with attenuation periods less than 60 ms in this bomb.