CFD Simulation of Hypersonic TBCC Inlet Mode Transition

Slater, John W.; Saunders, John D.

doi:10.2514/6.2009-7349

Cited by 13 publications

(6 citation statements)

References 3 publications

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“…Similar responses were recorded when disturbances were applied to the LS Path ramp position. These simulation results agree with known CFD results, that the LS Path normalshock position is sensitive to changes in ramp and cowl position 10 . Hence, it is necessary to fine-tune actuators control parameters to avoid servo oscillations and reduce the probability of inlet unstart during mode transition.…”

Section: The Simulation Results Insupporting

confidence: 82%

“…As mentioned earlier, this is not possible if the LS Path cowl angle is fixed at zero-degree. These simulation results agree with CFD analyses 10 , that it is possible to achieve good stability and performance for inlet mode-transition with air-bypass control, combined with proper handling of inlet variable-geometry and matching exit-flow BC's.…”

Section: B Mode-transition Control Simulationsupporting

confidence: 79%

“…The implemented simulation is applicable to a wide range of free-stream and exit-flow conditions. Preliminary simulation results show general agreements with CFD predictions 10 of inlet mode-transition dynamics and stability. In addition, the simulation results show that inlet back-pressure dynamics is likely to be an important factor in mode-transition control.…”

Section: Discussionsupporting

confidence: 58%

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A Framework for Simulating Turbine-Based Combined- Cycle Inlet Mode-Transition

Vrnak²,

Slater³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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A simulation framework based on the Memory-Mapped-Files technique was created to operate multiple numerical processes in locked time-steps and send I/O data synchronously across to one-another to simulate system-dynamics. This simulation scheme is currently used to study the complex interactions between inlet flow-dynamics, variable-geometry actuation mechanisms, and flow-controls in the transition from the supersonic to hypersonic conditions and vice-versa. A study of Mode-Transition Control for a high-speed inlet windtunnel model with this MMF-based framework is presented to illustrate this scheme and demonstrate its usefulness in simulating supersonic and hypersonic inlet dynamics and controls or other types of complex systems. Nomenclature

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Section: The Simulation Results Insupporting

confidence: 82%

Section: B Mode-transition Control Simulationsupporting

confidence: 79%

Section: Discussionsupporting

confidence: 58%

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A Framework for Simulating Turbine-Based Combined- Cycle Inlet Mode-Transition

Vrnak²,

Slater³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

Self Cite

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“…The operation mode transition from turbojet to ramjet is also one of the important research directions for TBCC propulsion systems. In 2009, Slater et al carried out a steady-state CFD simulation at different splitter cowl positions (0, −2.0, −4.0, −5.7 deg) for the inlet mode transition flow field at Mach 4 from turbine flow-path to parallel dualmode ramjet/scramjet in a TBCC propulsion system [14]. Research indicated the accurate modeling of shock waves, boundary layers and porous bleed regions were dominant factors for assessing the inlet static and total pressure, bleed flow rates and bleed plenum pressures [14].…”

Section: Introductionmentioning

confidence: 99%

Parametric Research and Aerodynamic Characteristic of a Two-Stage Transonic Compressor for a Turbine Based Combined Cycle Engine

Shi

2022

Aerospace

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This paper researches the parametric optimization of a two-stage transonic compressor having a large air bypass at partial rotating speed according to flow analysis for a turbine-based combined cycle engine (TBCC). To obtain adequate thrust, the inlet transonic compressor of the turbofan part of the TBCC is required to have a wider frequently used corrected rotating speed range and a larger mass-flow rate at low rotating speed, which is different from a typical transonic compressor. The one-dimensional blade design parameters and flow path of the baseline two-stage transonic compressor are introduced. With the widely used CFD software Numeca, the three-dimensional flow fields of the baseline transonic compressor and effects of the flow path between Stage 1 and Stage 2 on the inlet mass flow rate are analyzed for indicating the further improvement direction. For design speed (NC = 1.0), to improve the efficiency at the design point, parametric research is carried out on Rotor 2 to optimize the shock structure and strength, resulting in enhanced efficiency at the design point due to reduced shock loss of Rotor 2. For partial speed (NC = 0.8 and 0.7), since the flow field analysis indicates that the flow blockage in S1 limits the entire mass flow rate, the parametric redesign of stator S1 aims at obtaining an increased blade throat width to enhance the flow capacity of S1. Simulation confirms the increase in the mass-flow rate and efficiency at partial speed due to the reduction in flow blockage and related viscous losses. Aerodynamic analysis at representative operation points indicates that the modifications of R2 and S1 lead to obvious aerodynamic improvement at all rotating speeds (NC = 1.0 to 0.7), while maintaining sufficient stall margin.

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“…1; a diverter door will rotate to close the low-speed flow path as the high-speed engine takes over. This low-speed mode transition is very critical since unstart of the lowspeed inlet and the high-speed inlet might occur [8]. The opening and closing of the nozzle doors of the separate flow paths as well as the interaction of the two exhaust streams are the operational challenges that are inherent in this type of TBCC configuration.…”

Section: Introductionmentioning

confidence: 99%

Design and Experimental Study of an Over-Under TBCC Exhaust System

Mo¹,

Xu²,

Zhang

2013

Journal of Engineering for Gas Turbines and Power

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Turbine-based combined-cycle (TBCC) propulsion systems have been a topic of research as a means for more efficient flight at supersonic and hypersonic speeds. The present study focuses on the fundamental physics of the complex flow in the TBCC exhaust system during the transition mode as the turbine exhaust is shut off and the ramjet exhaust is increased. A TBCC exhaust system was designed using methods of characteristics (MOC) and subjected to experimental and computational study. The main objectives of the study were: (1) to identify the interactions between the two exhaust jet streams during the transition mode phase and their effects on the whole flow-field structure; (2) to determine and verify the aerodynamic performance of the over-under TBCC exhaust nozzle; and (3) to validate the simulation ability of the computational fluid dynamics (CFD) software according to the experimental conditions. Static pressure taps and Schlieren apparatus were employed to obtain the wall pressure distributions and flow-field structures. Steady-state tests were performed with the ramjet nozzle cowl at six different positions at which the turbine flow path were half closed and fully opened, respectively. Methods of CFD were used to simulate the exhaust flow and they complemented the experimental study by providing greater insight into the details of the flow field and a means of verifying the experimental results. Results indicated that the flow structure was complicated because the two exhaust jet streams interacted with each other during the exhaust system mode transition. The exhaust system thrust coefficient varied from 0.9288 to 0.9657 during the process. The CFD simulation results agree well with the experimental data, which demonstrated that the CFD methods were effective in evaluating the aerodynamic performance of the TBCC exhaust system during the mode transition.

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CFD Simulation of Hypersonic TBCC Inlet Mode Transition

Cited by 13 publications

References 3 publications

A Framework for Simulating Turbine-Based Combined- Cycle Inlet Mode-Transition

A Framework for Simulating Turbine-Based Combined- Cycle Inlet Mode-Transition

Parametric Research and Aerodynamic Characteristic of a Two-Stage Transonic Compressor for a Turbine Based Combined Cycle Engine

Design and Experimental Study of an Over-Under TBCC Exhaust System

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