Nozzle Performance Maps for Fluidic Thrust Vectoring

Abstract

This Paper discusses the results of an experimental study to investigate the performance of a converging nozzle with fluidic thrust vectoring, using secondary-jet injection, through the measurements of various parameters such as thrust, flow rates, and pressures over a range of operating conditions. The thrust coefficient is found to be dependent on the nozzle pressure ratio (NPR) of the primary nozzle and momentum ratio or mass ratio of the primary and secondary mass flows. The vector angle is found to depend only on momentum ratio or mass ratio and independent of the NPR. The secondary-jet injection is observed to increase the magnitude of net thrust by reducing the effective flow area while reducing the thrust coefficient. It is established that four additional parameters, namely, the fluidic thrust vectoring coefficient, nondimensional mass flow rate of the core jet, nondimensional mass flow rate of secondary jet, and mass ratio, are required to describe the vectoring performance comprehensively. The mass ratio appears to be a suitable parameter for developing the control algorithms as the other dependent parameters are linear functions of the mass ratio. Using an example, a procedure to identify the operational zone over the nozzle characteristic map is demonstrated.