Preliminary Studies On Piston Motion Control Devices Of Heavy Piston Driver And Single Kerosene Droplet Supercritical Burning

This thesis focuses on development of a heavy piston driver with motion control devices for supercritical combustion of single droplet. To obtain long duration for test gas with high pressure and temperature,wedge type and step type brakes are designed and utilized in arresting piston driver at the end of compression. The phenomenological knowledge is obtained to demonstrate the accompanied mechanism,such as droplet supercritical combustion. The thesis includes:(1)In chapter one,the background,related progress and the primary coverage are briefly introduced in this thesis.(2)In chapter two,the overall structure of the heavy piston driver are demonstrated in this thesis,as well as schematic and size of some component complex.(3)In chapter three,two types of piston motion control devices are presented. In wedge type brake,four wedges slide in the ramped wall embedded annularly in the piston. Each ramp angle is determined by the friction coefficient. The rebounded piston can be shod by the raising wedge. In step type brake,whenever the piston moves out the end of compression tube,the eight pressed cylinders leap out from the annular holes dapped in the piston. The cylinders are stopped by the step and shear stress is balanced by the inertia force to arrest the piston. The pressure time history of compressed gas can be obtained for these herein brakes,and the brake effect is evaluated by p-t curves. Finally,the cylinders are replaced by the baffle plates to decrease stress concentration and avoid plates'damage.(4)In chapter four,the preliminary experiment of the kerosene droplet supercritical burning and the spark schiliren images are showed in this thesis.(5)In chapter five,some conclusions and suggestions for future study are illustrated .