Plume-Ducting System Design of Vertical Launcher Using Computational-Fluid-Dynamics Tools

摘要

Three-dimensional viscous simulations are carried out to study the underexpanded plume impingement in a confined environment. Unsteady Navier-Stokes equations are solved along with a k-e turbulence model using commercial computational-fluid-dynamic tools. The computational tool is first validated against experimental results of a static test of a rocket motor with cold gas as well as double base solid rocket propellant inside a launcher tube with a diameter slightly larger than the nozzle exit. The simulation captured all the pertinent flow features and the computed surface pressure matches well with the experimental results both for cold- and hot-flow cases. The validated computational methodology is used to design a compact plume-ducting system for a vertical launcher. The alternate ducting system includes a number of novel features like two uptakes, conical deflectors, a convergent duct, etc., compared to the conventional plume-ducting system. The new design exhibits much well-behaved flowfield inside the plenum chamber with much less fluctuations, and the structural load due to pressure is 2.8 times lower compared to a conventional design. It is found that cold air is entrained into the gas-gathering tank through the annular space between the canister and missile surface thus reducing the thermal load in a vertical-launch system.