振动筛板槽中液滴分散动力学的研究(Ⅰ)实验研究及理论分析

本文通过实验观察发现,液滴的破碎只有在液滴与振动筛板孔口发生碰撞时才发生.基于这个实验现象,建立了振动筛板槽内液滴破碎的新模型.把筛板孔口附近的剪应力作为破碎力,破碎速率可表示为:G(d)=C_12Af/H(?)~n_4(d/d_h)~n_5[1-(d_(cr)/d)~(2n_1+1)]~0.5n(d)液滴的凝聚可以按气体分子碰撞过程来处理.凝聚速率可以用下式表示:ω(d_1,d_2)=C_Ⅱ(d_1+d_2)~(7/3)∈~（1/3)[β_d∈~(2/3)d_1+d_2/σ(d_1+d_2）~（1/3）]~n_6n(d_1)n(d_2)

Droplet Dispersion Dynamics in Vibrating Plate Tank ( I ) Experimental Studies and Theoretical Analysis

The experiments were performed by applying step change of vibrating frequency in the perforated plate extraction tank. The drop size distribution and Sauter drop size(d32)were measured with photographic and light transmission methods. Experiments indicated that drop breakage only occurred during its collision with the hole of the plates. Therefore, the shear force adjacent to the holes of the plates should be considered as the drop breaking force. From this basic point of view, a new model of drop breakage rate has been derived. For the coalescence of drops in the liquid-liquid contactor, the drops must collide with each other with sufficient collision energy. An expression for binary coalescence rate of drops has been derived by assuming that the mechanism of drop collision in vibrating extraction tank is analogous to the collision between molecules in the kinetic theory of gases.