Plasma Actuator–Assisted Rocket Nozzle for Improved Launcher Performance

The need to avoid unstable separations and side loads during low-altitude operations imposes a strict limit on the nozzle expansion ratio of launchers propulsion systems. Remarkable performance losses are consequently induced. An innovative concept is here presented that overcomes this limit. Plasma actuators are proposed as a means to stabilize separation in highly overexpanded conventional bell-shaped nozzles. A larger expansion ratio can thus be adopted in boosters and first-stage engines, and their vacuum specific impulse is increased. The concept is here assessed by means of Reynolds-averaged Navier–Stokes simulations. The effects of the plasma actuators are described by average body force and heat source terms. The potentialities of this concept, adaptable to any bell-shaped nozzle, are assessed evaluating the possible payload gain for a representative case. The results show that the proposed concept allows for suitable payload growth and engine flexibility.