Experimental and Numerical Investigations of a Bypass Dual Throat Nozzle

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
Rui Gu ◽  
Jinglei Xu ◽  
Shuai Guo
Keyword(s):  
Computational Study ◽  
Minimum Area ◽  
Thrust Vectoring ◽  
Thrust Vector ◽  
Vector Angle ◽  
Vectored Thrust ◽  
Fluidic Thrust Vectoring ◽  
Secondary Injection ◽  
Maximum Thrust ◽  
Thrust Performance

The bypass dual throat nozzle (BDTN) is a new kind of fluidic vectoring nozzle. A bypass is set between the upstream convergent section and upstream minimum area based on the conventional dual throat nozzle (DTN). The BDTN shows a minimum or even no penalty on the nozzle's thrust performance, while it would be able to produce steady and efficient vectoring deflection similar to the conventional DTN. A BDTN model has been designed and subjected to experimental and computational study. The main results show that: (1) BDTN does not consume any secondary injection from the other part of the engine, while it can produce steady and efficient vectoring deflection. (2) Under the same condition, it can provide the maximum thrust vectoring efficiency of all the known fluidic thrust vectoring concepts reported in the literature. (3) The thrust vector angle is also greater than that of the conventional DTN that has been reported up to now. Especially, under NPR = 10, the thrust vector angle of BDTN can reach 21.3 deg. (4) For a wide NPR range from 2 to 10, the BDTN generates the best thrust vectoring performance under NPR = 4. Above all, the BDTN is well suited to produce vectored thrust for nozzles.

scholarly journals Numerical Analysis of Bypass Mass Injection on Thrust Vectoring of Supersonic Nozzle

2018 ◽  
Vol 179 ◽  
pp. 03014
Author(s):  
Md Shafiqul Islam ◽  
Md. Arafat Hasan ◽  
A.B.M. Toufique Hasan
Keyword(s):  
High Speed ◽  
Passive Control ◽  
Rectangular Channel ◽  
Supersonic Nozzle ◽  
Shock Structure ◽  
Thrust Vectoring ◽  
Mass Injection ◽  
Thrust Vector ◽  
Vector Angle ◽  
Thrust Performance

High speed aerospace applications require rapid control of thrust (i.e. thrust vectoring) in order to achieve better manoeuvrability. Among the existing technologies, shock vector control is one of the efficient ways to achieve thrust vectoring. In the present study, bypass mass injection (passive control) was used to generate shock vectoring in a planar supersonic Converging-Diverging (CD) nozzle. Two diffenrent bypass lines were used to inject mass in the diverging section varying their dimension in the span wise direction (10 mm ×10 mm2 square channel and 2.68 mm×38 mm2 rectangular channel) in such a way that, the mass flow ratio in both the case remain the same (4.9%) in order to compare the effect of bypass channel dimension in the resulting thrust vector angle and thrust performance. Reynolds-averaged Navier-Stokes (RANS) equations with k-omega SST turbulence model have been implemented through numerical computations to capture the three-dimensional steady characterstics of the flow field. Results showed a significant change in the shock structure with the fromation of recirculation zone near the bypass injection port in both the case with a variation of shock structure and thrust performance for different geometry bypass lines. It was found that, thrust vector angle increases as injection length increases in the span wise direction.

An Investigation of Flow Characteristics and Parameter Effects for a New Concept of Hybrid SVC Nozzle

2018 ◽  
Author(s):  
F. Song ◽  
J. W. Shi ◽  
L. Zhou ◽  
Z. X. Wang ◽  
X. B. Zhang
Keyword(s):  
Static Pressure ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Exhaust System ◽  
Aircraft Engine ◽  
Thrust Coefficient ◽  
Thrust Vectoring ◽  
Static Pressure Distribution ◽  
Thrust Vector ◽  
Vector Angle

Lighter weight, simpler structure, higher vectoring efficiency and faster vector response are recent trends in development of aircraft engine exhaust system. To meet these new challenges, a concept of hybrid SVC nozzle was proposed in this work to achieve thrust vectoring by adopting a rotatable valve and by introducing a secondary flow injection. In this paper, we numerically investigated the flow mechanism of the hybrid SVC nozzle. Nozzle performance (e.g. the thrust vector angle and the thrust coefficient) was studied with consideration of the influence of aerodynamic and geometric parameters, such as the nozzle pressure ratio (NPR), the secondary pressure ratio (SPR) and the deflection angle of the rotatable valve (θ). The numerical results indicate that the introductions of the rotatable valve and the secondary injection induce an asymmetrically distributed static pressure to nozzle internal walls. Such static pressure distribution generates a side force on the primary flow, thereby achieving thrust vectoring. Both the thrust vector angle and vectoring efficiency can be enhanced by reducing NPR or by increasing θ. A maximum vector angle of 16.7 ° is attained while NPR is 3 and the corresponding vectoring efficiency is 6.33 °/%. The vector angle first increases and then decreases along with the elevation of SPR, and there exists an optimum value of SPR for maximum thrust vector angle. The effects of θ and SPR on the thrust coefficient were found to be insignificant. The rotatable valve can be utilized to improve vectoring efficiency and to control the vector angle as expected.

Coanda Surface Geometry Optimization for Multi-Directional Co-Flow Fluidic Thrust Vectoring

2009 ◽  
Author(s):  
Fariborz Saghafi ◽  
Afshin Banazadeh
Keyword(s):  
Deflection Angle ◽  
Flow Characteristics ◽  
Geometric Parameters ◽  
Nozzle Geometry ◽  
Surface Geometry ◽  
Thrust Vectoring ◽  
Affective Factors ◽  
Optimization Parameters ◽  
Fluidic Thrust Vectoring ◽  
Maximum Thrust

The performance of Co-flow fluidic thrust vectoring is a function of secondary flow characteristics and the fluidic nozzle geometry. In terms of nozzle geometry, wall shape and the secondary slot aspect ratio are the main parameters that control the vector angle. The present study aims to find a high quality wall shape to achieve the best thrust vectoring performance, which is characterized by the maximum thrust deflection angle with respect to the injected secondary air. A 3D computational fluid dynamics (CFD) model is employed to investigate the flow characteristics in thrust vectoring system. This model is validated using experimental data collected from the deflection of exhaust gases of a small jet-engine integrated with a multi-directional fluidic nozzle. The nozzle geometry is defined by the collar radius and its cutoff angle. In order to find the best value of these two parameters, Quasi-Newton optimization method is utilized for a constant relative jet momentum rate, a constant secondary slot height and insignificant step size. In this method, the performance index is described as a function of thrust deflection angle. Optimization parameters (wall geometric parameters) are estimated in the direction of gradient, with an appropriate step length, in every iteration process. A good guess of initial optimization parameters could lead to a rapid convergence towards an optimal geometry and hence maximum thrust deflection angle. Examination over a range of geometric parameters around the optimum point reveals that this method promises the best performance of the system and has potential to be employed for all the other affective factors.

scholarly journals Thrust Vectoring of a Fixed Axisymmetric Supersonic Nozzle Using the Shock-Vector Control Method

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 441
Author(s):  
Emanuele Resta ◽  
Roberto Marsilio ◽  
Michele Ferlauto
Keyword(s):  
Vector Control ◽  
Control Method ◽  
Supersonic Nozzle ◽  
Three Dimensional ◽  
Axisymmetric Nozzle ◽  
Optimal Position ◽  
Thrust Vectoring ◽  
Thrust Vector ◽  
Secondary Air ◽  
Fluidic Thrust Vectoring

The application of the Shock Vector Control (SVC) approach to an axysimmetric supersonic nozzle is studied numerically. SVC is a Fluidic Thrust Vectoring (FTV) strategy that is applied to fixed nozzles in order to realize jet-vectoring effects normally obtained by deflecting movable nozzles. In the SVC method, a secondary air flow injection close to the nozzle exit generates an asymmetry in the wall pressure distribution and side-loads on the nozzle, which are also lateral components of the thrust vector. SVC forcing of the axisymmetric nozzle generates fully three-dimensional flows with very complex structures that interact with the external flow. In the present work, the experimental data on a nozzle designed and tested for a supersonic cruise aircraft are used for validating the numerical tool at different flight Mach numbers and nozzle pressure ratios. Then, an optimal position for the slot is sought and the fully 3D flow at flight Mach number M∞=0.9 is investigated numerically for different values of the SVC forcing.

scholarly journals Computational study of Coanda based Fluidic Thrust Vectoring system for optimising Coanda geometry

2016 ◽  
Vol 149 ◽  
pp. 012210 ◽  
Author(s):  
R Bharathwaj ◽  
P Giridharan ◽  
K Karthick ◽  
C Hari Prasath ◽  
K Prakash Marimuthu
Keyword(s):  
Computational Study ◽  
Thrust Vectoring ◽  
Fluidic Thrust Vectoring

scholarly journals Research on control effectiveness of fluidic thrust vectoring

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042199813
Author(s):  
Fei Xue ◽  
Gu Yunsong ◽  
Yuchao Wang ◽  
Han Qin
Keyword(s):  
High Altitude ◽  
Ground State ◽  
Deflection Angle ◽  
Internal Flow ◽  
Lateral Force ◽  
Control Surface ◽  
Low Density ◽  
Thrust Vectoring ◽  
Density State ◽  
Fluidic Thrust Vectoring

In view of the control effects of fluidic thrust vector technology for low-speed aircraft at high altitude/low density and low altitude/high density are studied. The S-A model of FLUENT software is used to simulate the flow field inside and outside the nozzle with variable control surface parameters, and the relationship between the area of control surface and the deflection effect of main flow at different altitudes is obtained. It is found that the fluidic thrust vectoring nozzle can effectively control the internal flow in the ground state and the high altitude/low density state. and the mainstream deflection angle can be continuously adjusted. The maximum deflection angle of the flow in the ground state is 21.86°, and the maximum deviation angle of the 20 km high altitude/low density state is 18.80°. The deflecting of the inner flow of the nozzle is beneficial to provide more lateral force and lateral torque for the aircraft. The high altitude/low density state is taken as an example. When the internal flow deflects 18.80°, the lateral force is 0.32 times the main thrust. For aircraft with high altitude and low density, sufficient lateral and lateral torque can make the flying aircraft more flexible, which can make up the shortcomings of the conventional rudder failure and even replace the conventional rudder surface.

Effect of Control Parameters of Secondary Jet on Fluidic Thrust Vectoring

2014 ◽  
Vol 998-999 ◽  
pp. 613-616
Author(s):  
Li Li ◽  
Dong Ping Wang ◽  
Tsutomu Saito
Keyword(s):  
Flow Field ◽  
Control Parameters ◽  
Jet Injection ◽  
Specific Design ◽  
Initial State ◽  
Thrust Vectoring ◽  
Original Hypothesis ◽  
Fluidic Thrust Vectoring

The flow field was simulated in a 2D convergent-divergent nozzle, for fluidic thrust vectoring with N-S method. Based on the specific design, the effects of control parameters of secondary jet injection is investigated, and a method is proposed to calculate the initial state of secondary jet, which is different from original hypothesis of stagnation. The results showed that the two methods have closed results and the stagnation hypothesis is suitable for the calculation of the initial state of secondary jet.

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