Drop deformation in uniaxial extensional flow fields in microgravity

A liquid bridge stretching technique was developed to measure the deformati on of single emulsion drops in pure uniaxial extensional flow. The experime nts are carried out an the drop-tower facility of ZARM at the University of Bremen which provides microgravity conditions of about 10(-6) g for 4.7 s. The liquid bridge is generated in microgravity and held between two disks by surface tension. The bridge is stretched exponentially to a maximum leng th of one meter and the disk diameters are reduced exponentially in order t o preserve the cylindrical bridge contour. The fluid bridge device makes dr op deformation experiments possible with emulsion drops of any density and wide spreaded viscosity ratios. A result of this project is the specificati on of the time dependence of the deformation and the estimation of the drop stability limit in relation to the capillary number and the viscosity rati o.