Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process

Abstract

The dual throat nozzle (DTN) technique is capable to achieve higher thrust-vectoring efficiencies than other fluidic techniques, without compromising thrust efficiency significantly during vectoring operation. The excellent performance of the DTN is mainly due to the concaved cavity. In this paper, two DTNs of different scales have been investigated by unsteady numerical simulations to compare the parameter variations and study the effects of cavity during the vector starting process. The results remind us that during the vector starting process, dynamic loads may be generated, which is a potentially challenging problem for the aircraft trim and control.

Experimental and Numerical Investigations of a Bypass Dual Throat Nozzle

“…The mainstream appears as V shape and forms a steady and efficient thrust vector jet. The flow structure of the upper side is open cavity flow [19]. These phenomena that occurred in the measured data are excellently reproduced by the numerical simulation.…”

“…The dynamic viscosity is assumed to be constant, and the gravity effect can be neglected. Based on these conditions, the conservation equations, together with the ideal gas equation, can be expressed as following: flow-field model [19]. Followed by, the numerical method being checked at first by experiment data [15].…”

Experimental and numerical investigation of an axisymmetric divergent dual throat nozzle

“…Other computational and experimental researches were also executed 17–19 and a two-dimensional (2D) divergent DTN was investigated to acquire large thrust vector angles. 19–21…”

“…Even though, the thrust-vector angle of the DTN responds extremely quickly and the dynamic hysteresis time is very small. 20,21 In addition, the dynamic response of the DTN system is nonlinear caused by the introduction of strong nonlinearities (e.g. shock waves and flow separations).…”

“…Other computational and experimental researches were also executed [17][18][19] and a twodimensional (2D) divergent DTN was investigated to acquire large thrust vector angles. [19][20][21] For the divergent DTN, as the NPR increases, the normal shock wave begins to appear and moves downstream, but remains inside the cavity. In addition, the shock wave structure is not changed with the increase of in the NPR.…”