Visualization experiment on the ignition performance and flame-spreading in different charging structures

In order to investigate the influence of different charging structures on the ignition performance and its influence on the particle movement before and after the film rupture of the chamber, a visualization experiment platform of the chamber was designed and built, and the stage tests of the ignition of the full particle charging, partial particle charging, mixed before and after the rod-particle charging and the full rod charging were carried out. The experiment shows that the free space will cause the flame propagation speed to increase significantly, from 77 m/s in the charge area to 575 m/s, and there will be pressure fluctuations in several areas of the chamber. The ignition performance of the rod is obviously better than that of the granular, and the pressure fluctuation in the chamber is smaller, the peak ignition gas pressure in the rod charge structure is only 50 % of that in the granular charge structure (1.6 MPa:3.2 MPa), and the maximum pressure difference is only 20 % of that in the granular propellant structure (0.5 MPa:2.5 MPa). The rod-particle mixed charge bed has good ignition consistency in the rod charge area, and when it reaches the granular charge area, the flame will be significantly hindered. The rod basically stays still during the ignition process in the chamber, while the granular will move with the gas flow when there is free space, and after the film is broken, the particle movement is faster than that before the film is broken.