Numerical modeling of coanda effect in a novel propulsive system

Abstract

Coanda effect (adhesion of jet flow over curved surface) is fundamental characteristics of jet flow. In the present paper, we carried out numerical simulations to investigate Coanda flow over a curved surface and its application in a newly proposed Propulsive system “A.C.H.E.O.N” (Aerial Coanda High Efficiency Orienting jet Nozzle) which supports thrust vectoring. The ACHEON system is presently being proposed for propelling a new V/STOL airplane in European Union. This system is based on cumulative effects of three physical effects such as (1) High speed jet mixing speeds (2) Coanda effect control by electrostatic fields (3) Coanda effect adhesion of an high speed jet to a convex surface. The performance of this nozzle can be enhanced by increasing the jet deflection angle of synthetic jet over the Coanda surface. This newly proposed nozzle has wide range of applications. It can be used in industrial sector such as plasma spray gun and for direct injection in combustion chamber to enhance the efficiency of the combustion chamber. Also, we studied the effect of Dielectric barrier discharge (DBD) plasma actuators on A.C.H.E.O.N system. Dielectric barrier discharge (DBD) plasma actuators are active control devices for controlling boundary layer and to delay the flow separation over any convex surfaces. Computations were performed under subsonic condition. Two dimensional CFD calculations were carried out using Reynolds averaged Navier stokes equations (RANS). A numerical method based on finite volume formulation (FVM) was used. SST k-ω model was considered to model turbulent flow inside nozzle. DBD model was used to model the plasma. Moreover, a body force treatment was devised to model the effect of plasma and its coupling with the fluid. This preliminary result shows that, the presence of plasma near Coanda surface accelerates the flow and delays the separation and enhances the efficiency of the nozzle.