喷嘴气泡脱离直径的计算

Calculation of Detachment Diameter of A Nozzle Bubble

根据喷嘴气泡的蝌蚪形状特点,给出了物理模型.依此模型建立了力学平衡方程,导出了计算喷嘴气泡脱离直径的迭代公式.它包含了流体的重要物性参量、喷嘴直径以及气体流量,因此具有广泛的适用性.此式除与作者的实验相符外,还与其他研究者的实验在粘度、表面张力、喷嘴直径和气体流量的宽广范围内符合得很好.

According to the configuration of a real nozzle bubble, the author proposes a physical model which describes the nozzle bubble as a tadpole structure. Unlike a spherical bubble, the long tail part of a tadpole bubble has great influence on the inertia force and the drag force acting on the bubble. Thereupon, the author discusses the bouyancy force, the inertia force, the drag force and the surface tension force acting on a nozzle bubble in equilibrium before detachment takes place. An iteration equation for calculating bubble detachment diameter is estableshed which contains all the important factors of the liquid phase physical properties, the nozzle diameter and the gas rate. The calculated detachment diameter is in good agreement with experimental observations in almost all ranges of the above mentioned parameters. Various individual cases are calculated with high accuracy by this iteration equation as compared with equations of other investigations, and the causes of deviation oi the latter ones are discussed.