Experimental Research And Numerical Simulation On Gas Flow Characteristics In Concentric Canister Launcher

The flow characteristics of gas which is affected by the concentric canister structure and goes through a series of complicated changes after exhausted from the engine is study in this paper. Analyzing the influent factors of concentric canister launcher gas flow state in detail are through shrink ratio experiment and numerical simulation method. The result could provide a theoretical support for the design of increase thrust and improved design of concentric canister launcher.In the cold gas jet experimental research, a small-scale experiment system and flow characteristics measurement scheme of concentric canister was established based on the Maher similarity criterion. Under the same experimental conditions, the pressure of the jet impingement and flow could fluctuate, which shown that the flow, shock and turbulence development process of the jet had obvious unsteady characteristics. In the gap flow area, the air pressure was gradually decreased along the flow direction, which indicated that the gas flown in the gap area was accompanied by the pressure loss. In the case of different jet impingement heights, the jet impingement pressure and the air pressure in the inner and outer space were changed with the change of the jet impact height.In numerical calculation, the Reynolds average method was used to simulate the flow field in concentric cylinder. The typical flow state was studied. The reasons for the increase of thrust were analyzed, and the factors that affect the gas flow in concentric cylinders were analyzed one by one. When the factors satisfy certain conditions, the airflow would place at the outlet, affected the airflow to be discharged out of the cylinder, increased the pressure on the bottom of the projectile, and came into being the increasing thrust; in order to improve the total pressure, increasing the length of the gap, reducing gap width, increasing of nozzle throat diameter or increasing the impingement distance would be the way, which would result in the increase of projectile base pressure, so that the thrust could be increased.