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Showing 4 results for Thrust Vector Control
Mojtaba Tahani, Mohammad Hojaji, Mohammad Salehifar, Arash Dartoomian,
Volume 15, Issue 8 (10-2015)
Abstract
Effects of secondary sonic jet injection in divergent part of supersonic nozzle on flow field structure and thrust vector control performance has been numerically analyzed. Three dimensional multi-blocks extended numerical code has been used to model the complexity of turbulence flow by k-ω SST model. Structured computational domain has been applied and initial results of simulation validated with previous experimental results. The obtained numerical results are compared with the experimental ones, and the outcome shows acceptable agreement between the two. Different injection power generates by varying the injection surface and pressure ratio with respect to throat pressure. Injection power increment make changes in performance and also sometimes it lowers the performance. In the current research aside from complete complex flow features description, allowable power range to increase system performance has been presented. In this range, increasing the injection mass flow rate, decreases the amplification factor, but increases the deflection angle and axial thrust augmentation as most important performance parameters. Out of estimated range for allowable mass power injection, performance parameters different behavior differently that shows a drastic drop in performance.
Mohammad Reza Najjari, Mohammad Reza Heidari,
Volume 16, Issue 3 (5-2016)
Abstract
One way to control the position of the missile is controling thrust vector that is moves with help of thrust due to exit of gas. All thrust vector control (TVC) methods are independent of aerodynamic forces of atmosphere and until the engine has thrust, maintain their performance. Secondary injection systems are one of the four major TVC methods. In this study,at first identify the components and design entire conceptualdesigning of system and the preliminary design of manifold of a type of thrust vector control system using a liquid injection thrust vector control (LITVC)has been proceed. Then the layouts of components on some components such as injectors and reservoirs, as well as detailed design of the system are discussed. Then the numerical simulation of flow and the designing and studying the sprayers in LITVC systems will be discussed. Also numerical designing and simulation in two parts: injection system and the injector spray effects into the main flow are analyzed and the results are presented and validated. The achievement of this study can be used as a model for designing and analyzing of various kinds of TVC systems with lateral fluid method on a variety of missiles with different launchers.
D. Mokhtari , M. Hojaji , M. Afrand ,
Volume 19, Issue 5 (5-2019)
Abstract
In this study, the effect of a cylindrical protuberance on the thrust vector of a supersonic jet was investigated as a new method in thrust vector control. For this purpose, a convergent-divergent nozzle was designed and constructed. This nozzle is such that the Mach number is its nominal output in full expansion conditions 2. The wall of the nozzle is equipped with pressurized holes to measure pressure variations. Also, there is a duct wall in the nozzle wall to apply a protuberance inside the nozzle. Pressure sensors for pressure measurement and also the schlieren system are used to check the outlet flow field. The total pressure of the compartment is constant at all tests and is 5.7bar. The results of this study show that the depth of penetration of the protuberance in the flow field has a significant effect on the amount of deviation and even the direction of the deviation of the jet stream exited from the convergent-divergent nozzle. The maximum jet outlet flow from the nozzle is 5.7degrees, which occurred at a rate of H/D*=0/4. In addition, these results indicate that with the increase in bulge penetration within the nozzle, the nozzle axial thrust has slightly decreased.
M.r. Babaeyan , M. Hojaji,
Volume 19, Issue 7 (7-2019)
Abstract
In this study, the effect of the use of dual protuberances as a thrust vector control method in a supersonic convergent-divergent nozzle with a Mach number of 2 is experimentally investigated. The nozzle total pressure in all experiments is considered constant. Air is the working fluid in these experiments. The used protuberances are two cylindrical elements that are placed in front of the flow in the divergent part of the nozzle. These protuberances are installed at 60% and 90% of the length of the nozzle divergent portion from the nozzle throat and are simultaneously applied in the main flow path. The protuberances are installed in opposite walls. Effect of changing the penetration ratio of the protuberances [H/D] on the thrust vector angle and the components of the thrust vector is obtained by measuring the forces acting on the nozzle. Also, the flow field was measured by a Schlieren system, as well as, the pressure variations on the nozzle walls were measured. The results show that the use of dual protuberances can have a significant effect on the angle of the thrust vector and increase the angle of the thrust vector up to 4.35 degrees in the implemented conditions of this study. Also, the results reveal that this method can reduce the axial component of thrust up to 5.5% in the worst case of implemented conditions.
