Design Optimization of Grids in Grid Fins for Spacecrafts

Abstract

Grid fins are a type of aero control surfaces used in missiles and rockets in place of more conventional control surfaces such as the planar fins. Conventional planar fins are designed like miniature wings whereas grid fins have smaller lattice aerostructures arranged within a box-like structure. Most grid fins have square grid aerostructures such as those used in the Falcon 9 rocket manufactured by SpaceX. This paper discusses the introduction of 3 innovative designs namely trapezoidal, triangular and hexagonal grids in two configurations - un-tapered and tapered. The taper angles will be 6, 6.5, 7 and 7.5. These new designs will be modelled and analysed using suitable software. The designed grid fins will be simulated in multiple aerodynamic conditions at various angles of attack. The exit velocity of air at the outlet of the grid fin will be measured and analysed in this paper. Once the simulation is complete, the two best designs will be 3D printed with appropriate materials at appropriate scales for wind tunnel testing. The results will be compared and validated with existing data in order to find the overall effectiveness of the designs.