Experimental Study of Unsteady Flow in a Shock Tube for Needle-Free Drug Delivery

Recently, the needle-free delivery system has been widely used in medical fields due to its convenience in delivering drug particles into human body without any external needles. In order to penetrate through the outer layer of the skin, drug particles need to obtain enough momentum, which is achieved by accelerating drug particles in a Contoured Shock Tube (CST). The CST consists of a micro shock tube with two diaphragms and an expanded supersonic nozzle. In the present study, experimental studies were carried out by pressure measurement. Six high sensitive pressure transducers were used for recording pressure changes as the shock wave moved through different locations along walls in the test section. From which, data on shock wave propagation could be obtained. Different diaphragm pressure ratios were conducted to demonstrate effects of initial diaphragm pressure ratios on shock wave propagation. Shilieren visualization was also performed to observe shock wave propagation and shock wave structure in the present experimental shock tube model. The characteristic of the internal flow and shock wave system have been studied and analyzed in details in the present shock tube model.