.2-T-type Micro-channel Visualization Of Bubble Generation And Crushing Characteristics Experimental Study

Micro-bubbles have a large number of applications in the biomedical and pharmaceutical industries. The bubble size and the coefficient of variation affect the application satisfaction directly. Under most circumstance, reducing the bubble size and the coefficient of variation can improve the application results.It has recently been demonstrated that microchannel could be used to generate monodispersed bubbles and the bubble diameter is dominated by the hydro-diameter of microchannels. This is because the small length scales of this microfluidic device allow control over the formation of individual droplets. Smaller microbubble could be produced by reducing the microchannle diameter but it means the cost will fly highly. So developing a simple and effective method to reduce the bubble size appears very important. We propose a new microbubble generator called 2-T microchannel bubble generator which is combined by two T-jounctions of microchannels. This kind bubble generator can reduce the microbubble size to 50% as before without reducing microchannel diameter. In order to achieve the optimal design of such generators of fine and monodispersed bubbles, we need to elucidate the generation processes and how bubble size and distribution are controlled. We do this by visualizing and recording the bubble formation (characterized by the formation pattern, the bubble size and distribution) at the first T-junction and the bubble interaction/breakup at the second T-junction as we vary flow rates of two fluids, geometrical parameters of the system and properties of two fluids (castor oil and water) with a high speed digital imaging system equipped with a long distance microscope. The results are presented in the form of phase diagrams of bubble formation/breakup patterns.