Two new type criteria of deformation of a single droplet were introduced to estimate the effect of shear flow on deformation by the ratio of long radius to short radius or stretching rate, and they were analyzed and compared through the experiments. The experiments show that the ratio of long radius to short radius and stretching rate grow with the increase of shear velocity and the deformation shrinkage coefficient of a single droplet increases at first and then decreases. Compared with to the theoretical results it deviates greater with emulsifier. The shear stress attained by the stretching rate agrees better with the practical value than that by the ratio of long radius to short radius.

In order to study the feasibility of the shearing demulsification of W/O emulsion, a Couette double-cylinder device was designed to form a lamina flow, and its shear intensity was controlled by the rotate speed of the inner cylinder. The force of single droplet is analyzed according to hydrokinetics, and the affine deformation model is put forward and validated by experiment which basically agreed with Taylor G I and Cox R G theory. The results show that shear is propitious to droplets aggregation. Based on the relation curve of droplets diameter with the revolution of inner cylinder, it was found when the rotation velocity of inner cylinder is 50~150 r/min ( shearing strenghth of 8.67~26.01 Pa), the maximal diameter and average diameter are all larger than that of droplets which are not in shear flow. It was shown that shear can accelerate droplets aggregation only within a valid shear range. Therefore，a proper shear flow can be introduced into the separate device to improve the separate efficiency of W/O emulsion.