• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.27-34
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• 2011

A numerical analysis was peformed for the supersonic aircraft with variable pitch thrust vector nozzle. Based on the requirement of the mixed turbofan engine of the supersonic aircraft, two dimensional thrust vector nozzle with variable pitch angle was designed. To investigate the effect of the thrust vectoring nozzle, the numerical analysis was conducted by using Fluent under the several pitch deflection angle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.483-486
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• 2009

An investigation of the thrust vectoring nozzle which can be applied to the supersonic variable exhaust system was performed. The maximum mach number of the model aircraft is 1.8 and mission radius is about 400Nm. The cycle analysis are performed at each operating regime of the aircraft and the specifications of the thrust vectoring nozzle were developed. Based upon the requirement of the thrust vectoring nozzle, two dimensional thrust vectoring nozzle were designed and flow analysis was conducted by deflection of the pitch and yaw angle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.170-176
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• 2010

A numerical analysis was peformed for the supersonic aircraft with variable pitch thrust vector nozzle. Based on the requirement of the mixed turbofan engine of the supersonic aircraft, two dimensional thrust vector nozzle with variable pitch angle was designed. To investigate the effect of the thrust vectoring nozzle, the numerical analysis was conducted by using Fluent under the several pitch deflection angle.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.94-104
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• 2013

A numerical analysis has been conducted to determine the pitch thrust vectoring characteristics of a two-dimensional convergent divergent exhaust nozzle for supersonic aircraft application. The numerical analysis was done by using Fluent and verified by the experimental test results. Analysis was performed with pitch angle of $0^{\circ}$ and $20^{\circ}$ each at the ambient temperature condition. To see the effect of a ratio of pitch flap length and pitch flap height, the ratio was varied from 0.5 to 2.5. The numerical analysis shows that pitch thrust is changed greatly with pitch flap length. The big difference of the pitch thrust with pitch flap length is due to the shock interactions in the nozzle.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1637-1642
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• 2004

Experimental and computational studies were performed to investigate the effectiveness of a thrust vectoring method using a counterflow concept. A shadowgraph method was used to visualize the supersonic jet expanded from a two-dimensional convergent-divergent nozzle and deflected by a now suction. The primary nozzle pressure and suction nozzle pressure ratios are varied between 3.0 and 5.0, and between 0.2 and 1.0 respectively. The present experimental and computational results showed that, for a given primary nozzle pressure ratio, a decrease in the suction nozzle pressure ratio produced an increased thrust vector angle, and during the change processes of the suction pressure, a hysteresis effect of the thrust vectoring was found through the wall pressure distributions.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.84-93
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• 2013

Stealthy, high maneuverability and super cruise abilities are required for the next generation fighter and unmanned aircraft. Thrust vector control technique currently come into use to meet these requirements. In this experimental study, axial and pitch thrust were measured and Schlieren visualization were carried out using the scaled two dimensional thrust vector nozzles under various pitch deflection angle, pitch flap length and height. From the study, we could get the supersonic flow characteristics and draw an optimum geometric configuration of the two dimensional thrust vector nozzle.

• Journal of Energy Engineering
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• v.21 no.3
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• pp.237-242
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• 2012

This study presents numerical solutions of the two-dimensional Navier-Stokes equations for supersonic unsteady flow in a convergent-divergent nozzle with a isolator. The TVD scheme in generalized coordinates is employed in order to calculate the moving shock waves caused by thermal choking. We discuss on transient characteristics, unstart phenomena, fluctuations of specific thrust caused by thermal choking and effects of isolator. The adverse pressure gradient caused by heat addition brings about separation of the wall boundary layers and formation of the oblique shock wave that proceed to upstream. The proceeding speed of the oblique shock wave to upstream direction for the convergent-divergent nozzle with isolator is lower than that for the nozzle without isolator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.80-86
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• 2005

This study presents numerical solutions of the two-dimensional Navier-Stokes equations for supersonic unsteady flow in a convergent-divergent nozzle with heat addition. The TVD scheme in generalized coordinates is employed in order to calculate the moving shock waves caused by thermal choking. We discuss on transient characteristics, start and unstart phenomena, fluctuations of specific thrust caused by thermal choking and viscous effects. We prove that the control of separation of boundary layer is the most important key problem to prevent the thermal choking.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.356-363
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• 2012

This paper addresses an analytical study on the gas-solid two phase flows in a nozzle. The primary purpose is to get recognition into the gas-solid suspension flows and to investigate the particle motion and its influence on the gas flow field. The present study is the primal step to comprehend the gas-solid suspension flow in the convergent-divergent nozzle. This paper try to made a development of an analytical model to study the back pressure ratio, particles loading and the particle diameter effect on gas-solid suspension flow. Mathematical model of gas-solid two phase flow was developed based on the single phase flow models to solve the quasi-one-dimensional mass, momentum equations to calculate the steady pressure field. The influence of particles loading and particle diameter is analyzed. The results obtained show that the suspension flow of smaller diameter particles has almost same trend as that of single phase flow using ideal gas as working fluid. And the presence of particles will weaken the strength of the shock wave; the bigger particle will have larger slip velocity with gas flow. The thrust coefficient is found to be higher for larger particles/gas loading or back pressure ratio, but it also depends on the ambient pressure.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.1-7
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• 2002

In the modern propulsion systems, requited thrust is obtained using a nozzle. Sometimes shock and induced boundary layer separation is generated in an over-expanded convergent-divergent supersonic nozzle. It occurs because the nozzle expansion ratio is too large for a given nozzle pressure ratio (NPR). This phenomenon can be explained that it redefines effective nozzle geometry, shorer nozzle geometry and lower pressure ratio, in a given pressure ratio. Numerical studies were conducted about a fixed geometry 2D nozzle in overexpanded condition and compared with Hunter's experimental result. For the numerical simulation of the supersonic nozzle, Navier-Stokes equations are considered and as a turbulent model, $\kappa$-$\varepsilon$ /$\kappa$-$\omega$ blended SST two equation turbulent model is used. The characteristics of $\lambda$-shape shock systems due to the interaction of shock and boundary layer was investigated in a low NPR. And the result of comparison of thrust value shows that a fixed geometry nozzle can cover required flight mission.