Demonstration of Fluidic Throat Skewing for Thrust Vectoring in Structurally Fixed Nozzles

Abstract

The experimental demonstration of a fluidic, multiaxis thrust vectoring (MATV) scheme is presented for a structurally fixed, afterburning nozzle referred to as the conformal fluidic nozzle (CFN). This concept for jet flow control features symmetric injection around the nozzle throat to provide throttling for jet area control, and asymmetric injection to subsonically skew the sonic plane for jet vectoring. The conceptual development of the CFN was presented in a companion paper (Miller et al. [1]). In that study, critical design variables were shown to be the flap length and expansion area ratio of the nozzle, and the location, angle, and distribution of injected flow. Measures of merit were vectoring capability, gross thrust coefficient, and discharge coefficient. A demonstration of MATV was conducted on a 20 percent scale CFN test article across a range of nozzle pressure ratios (NPR), injector flow rates, and flow distributions. Both yaw and pitch vector angles of greater than 8 deg were obtained at NPR of 5.5. Yaw vector angles greater than 10 deg were achieved at lower NPR. Values of thrust coefficient for the CFN generally exceeded published measurements of shock-based vectoring methods. In terms of vectoring effectiveness (ratio of vector angle to percent injected flow), fluidic throat skewing was found to be comparable to shock-based vectoring methods.

Fundamentals and Applications of Modern Flow Control

“…This nozzle is representative of the type of nozzle installed in the next-generation vehicle concept shown in Fig. A detailed discussion can be found in the paper by Yagle et al (2001). A demonstration of MATV was conducted on a 20%-scale embedded fi xed-geometry nozzle test article across a range of nozzle pressure ratios (NPR), injector fl ow rates, and fl ow distributions.…”

Active flow control in supersonic nozzles

“…It helps the vehicle to meet take-off and landing requirements and it is a valuable control effector at low dynamic pressures, where traditional aerodynamic controls are less effective [2]. Fluidic Thrust Vectoring (FTV) retains the advantages of mechanical thrust vectoring without the need of the complex adjustable hardware of the variable geometry devices [3]. FTV strategies follow the principle of flow manipulation to obtain a lateral force on a nozzle of fixed geometry.…”

Numerical Investigation of the Dynamic Characteristics of a Dual-Throat-Nozzle for Fluidic Thrust-Vectoring

“…(9)(10)(11)(12)] are a simplification of the suction/ blowing model derived in [22] and are similar to the BCs for the flow inlet [28].…”

“…The fluidic throat-shifting method uses jets of secondary flow to create a new effective geometry at the throat and to turn the flow while it is still subsonic. It has minimal thrust losses but also suffers from low performance [4,9]. Better performances are achieved when throat shifting is applied to the dual-throat nozzle (DTN) concept.…”

“…Fluidic thrust vectoring (FTV) retains the advantages of mechanical thrust vectoring without the need of the complex adjustable hardware of the variable geometry devices [9]. FTV strategies follow the principle of flow manipulation to obtain a lateral force on a nozzle of fixed geometry.…”