立体旋流筛板并流时的流型特征及其操作域

Flow patterns characteristics and operating regions of a tridimensional rotational flow sieve tray in concurrent flow

流型影响气液通过塔板时传热传质效率,为了确定立体旋流筛板上不同喷淋密度Lw,空塔气相动能因子Fs的流型及其操作域,采用安装立体旋流筛板内构件的冷模实验塔,在Lw=39—260 m^3/(m^2·h),Fs=0.78—3.9(m/s)(kg/m^3)^(0.5)的操作条件下,测量立体旋流筛板内部差压脉动信号并记录流动照片。使用时域及标准偏差分析并结合流动图片的方法,主要考察了气液并流通过立体旋流筛板的流型特征及其操作域。实验结果表明:液相通量对各流型转变影响较大,Lw<70 m^3/(m^2·h)时为连续-分层流,Lw=70—145 m^3/(m^2·h)之间时为鼓泡-分层流或栓塞流,Lw>145 m^3/(m^2·h)为泡沫流;当Lw=70—145 m^3/(m^2·h)时,鼓泡-分层流和栓塞流的转变主要受气相通量Fs影响,Fs<1.95(m/s)(kg/m^3)^(0.5)为鼓泡-分层流,Fs>2.34(m/s)(kg/m^3)^(0.5)为栓塞流。

Flow patterns influence the heat and mass transfer efficiency during the gas-liquid flow through a tray. In order to know the patterns characteristics and operating regions at different Lw/Fsin a cold experimental model column within a tridimensional rotational flow sieve tray,under operating conditions of Lw= 39-260 m^3/( m^2·h),Fs= 0. 78-3. 90( m/s)( kg/m^3)^(0.5),differential pressure signals were collected and flow photos were taken. The flow patterns characteristics and operating regions were investigated using the method of time domain analysis,standard deviation analysis and flow photos when concurrent gas-liquid downward flow through the tray. The results show that the liquid flux makes a significant influence in patterns transformation. When Lw< 70 m^3/( m^2·h),it is continuous-stratified flow; when Lw= 70-145 m^3/( m^2·h),it is bubbling-stratified flow or plug flow; when Lw>145 m^3/( m^2·h),it is foam flow; and when Lw= 70-145 m^3/( m^2·h),transformation of bubbling-stratified flow and plug flow is affected by Fs,it is bubbling-stratified when Fs< 1. 95( m/s)( kg/m^3)^(0.5) and it is plug flow when Fs> 2. 34( m/s)( kg/·m^3)^(0.5).