Investigation Of Flows In An Irregular Section Concentric Canister Launcher

Some special missiles with irregular section or folding rudders/wings need to be launched by the concentric canister launch(CCL) system, which has many advantages to meet application requirements. For this issue, it is necessary to obtain properties of the flow filed through numerical calculation due to its small cost. Based on the physical features of the exhaust gas discharging from the canister, a three-dimensional Navier–Stokes equation considering compressible gas and k- ? turbulent model was established. Then, taking a CCL with a double- layer cylinder structure as an object, some characteristics were predicted, such as typical flow phenomena, interference effects and influence factors of the discharge gap. Subsequently, typical phenomena of the exhaust plume discharging from a CCL with the round-outside and square-inside section and a CCL with round-outside and triangle- inside section were researched.The results showed that: 1) The discharge gap has an important impact on the flow filed properties during missile moving in CCL. The pressure inner the tube could increase with the narrowing of the gap, which could be attributed to the hydraulic diameter of the gap. 2) Taking the irregular section, flow properties distributed on the section show a regular pattern due to the effect of the discharge section. 3) The round-outside and square- inside section has a better performance in push effect than a double-layer cylinder section, because the hydraulic diameter of the discharge gap of the former is little than the latter with the equivalent area. 4) The CCL with a round-outside and triangular- inside section generates a lighter load as well. 5) The push effect of the CCL with the round-outside and square- inside section are determined by the pressure of the tube bottom and related with the congestion state of the gap between inlet and outlet. Above all, results show the irregular-shape missiles can be lunched using the irregular-section CCLs, and analysis can also provide supports for enginee ring researches.