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Book Experimental Investigation of a Large scale Two dimensional Mixed compression Inlet System

Download or read book Experimental Investigation of a Large scale Two dimensional Mixed compression Inlet System written by Norman D. Wong and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large-scale, variable-geometry inlet model with a design Mach number of 3.0 was tested at Mach numbers from 1.55 to 3.2. Variable features of the inlet for off-design operation are an adjustable-height ramp system and a translating cowl. This report presents experimental results for a diffuser and boundary-layer bleed configuration which was optimized at the design Mach number. Overall performance was high with throat-mounted vortex generators, which were effective in reducing flow distortion in the subsonic diffuser at the higher Mach numbers.

Book A Supersonic Inlet engine Control Using Engine Speed as a Primary Variable for Controlling Normal Shock Position

Download or read book A Supersonic Inlet engine Control Using Engine Speed as a Primary Variable for Controlling Normal Shock Position written by Francis J. Paulovich and published by . This book was released on 1971 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cross-coupled inlet-engine control system concept is presented for a supersonic propulsion system consisting of a mixed- compression inlet and a turbojet engine. The control system employs manipulation of both bypass door flow area and engine speed to stabilize normal shock position in the inlet. Specifically, the case of slow-acting bypass doors used as a reset control where engine speed is the primary means of shock position control is described. Experimental results are presented showing performance of the control system with a NASA-designed inlet and a turbojet engine operating at Mach 2.5 in the Lewis 10- by 10-Foot Supersonic Wind Tunnel.

Book Numerical Simulation of a Mixed compression Supersonic Inlet Flow

Download or read book Numerical Simulation of a Mixed compression Supersonic Inlet Flow written by Joongkee Chung and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Control System Design Using Frequency Domain Models and Parameter Optimization with Application to Supersonic Inlet Controls

Download or read book Control System Design Using Frequency Domain Models and Parameter Optimization with Application to Supersonic Inlet Controls written by Robert C. Seidel and published by . This book was released on 1974 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Supersonic Inlet Investigation

Download or read book Supersonic Inlet Investigation written by Nasim F. Amin and published by . This book was released on 1971 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: A one-dimensional mathematical dynamic simulation model for predicting the transient behavior of air induction systems for advanced tactical aircraft operating in the supersonic portion of the flight spectrum is discussed. As a part of the simulation model, control system logic is included to provide control system design criteria necessary to maintain air induction system response to selected input disturbances within prescribed limits. The model is applicable to both external and mixed compression inlets operating at supersonic conditions. The 'lumped parameter' concept is used in simulating the dynamic response of the subsonic duct downstream of the terminal shock, with the duct divided into three lumps.

Book Coupled Supersonic Inlet engine Control Using Overboard Bypass Doors and Engine Speed to Control Normal Shock Position

Download or read book Coupled Supersonic Inlet engine Control Using Overboard Bypass Doors and Engine Speed to Control Normal Shock Position written by Gary L. Cole and published by . This book was released on 1970 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Interactive Design and Educational Tool for Supersonic External compression Inlets

Download or read book An Interactive Design and Educational Tool for Supersonic External compression Inlets written by Thomas J. Benson and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental and Numerical Characterization of a Generic Mixed Compression Supersonic Intake

Download or read book Experimental and Numerical Characterization of a Generic Mixed Compression Supersonic Intake written by Nikhil Khobragade and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The air intake captures the freestream airflow and delivers it to the engine of the parent vehicle for thrust production. The shockwave boundary layer interactions (SBLI) in the intake duct play an important role in defining the flow characteristics of supersonic air intakes. At certain operating conditions, these SBLI may result in large-amplitude oscillations in the intake flow, and be detrimental to the safety and performance of the engine. In addition, the back-pressure rise due to combustion instabilities can cause the intake to unstart. The unstart phenomenon generally turns out to be fatal for aerial vehicles due to loss of thrust and control. In spite of several previous studies focused on the intake unstart at certain operating conditions, a comprehensive understanding of flow states that occur during an unstart process is needed to develop a reliable engine control system. Both active and passive flow control techniques have been employed previously for the SBLI control to improve intake safety and performance. Particularly, cowl SBLI control has been targeted as it plays an important role in defining the performance and unstart characteristics of an intake. It has been shown in the literature that a simple backward-facing step (BFS) can be used as a passive control device for a canonical impinging SBLI. However, the use of a BFS has never been exploited for the SBLI control in supersonic air intakes. Previous studies led to the following questions. 1) Can a passive flow control device (suitably modified BFS) improve the performance of an air intake id est total pressure recovery and flow uniformity? 2) How does this passive flow control technique affect the mean flow behavior and dynamics of the air intake at different back-pressures? 3) Will there be any change in the intake unstart characteristics with SBLI control? To answer these questions as our research objectives and to improve our fundamental understanding of the supersonic intake flows, in particular the unstart phenomenon, a comprehensive experimental and numerical investigation is conducted and the results are presented in this work. The passive flow control device investigated in this study is a modified BFS, embedded at the ramp-isolator junction and is called a "Notch". The baseline intake geometry without a Notch is referred to as a Faceted configuration. The experiments include steady and unsteady wall pressure measurements, rake (total) pressures, back-pressure measurements, pressure sensitive-paint (PSP), planar particle image velocimetry (PIV), shadowgraphy, and oil flow visualizations. The numerical simulations include the Navier-Stokes-based mean flow Perturbation (NS-MFP) method for the linear analysis, Large Eddy Simulations (LES), and Reynolds Averaged Navier Stokes (RANS) simulations for the non-linear analysis. Numerical simulations predicted a region of flow separation and Kelvin-Helmholtz (K-H) instability around the isentropic compression surface of the external ramp. The ramp separation bubble also harbors a three-dimensional stationary instability that can induce transition under the influence of shear layer instability. The streamwise oriented G{\\\\"o}rtler vortices break down to turbulence due to secondary instabilities. The flow transitions to turbulence over the ramp before it enters the inlet-isolator duct. At low back-pressures, the inlet-isolator flow is predominantly two-dimensional (2D) and the shock train is located in the divergent section. The experiments displayed a comparatively higher level of pressure fluctuations and a fuller boundary layer in the Notched intake isolator. The LES demonstrated the underlying mechanisms at work is the mid-frequency energization through vortex shedding in a well-developed shear layer. The Notch results in lower static pressures and higher velocity fluctuations, which will reduce the structural loads while improving flow uniformity and total pressure recovery. At high back-pressures, the shock train moves upstream and transitions to an oblique shock train. The notch effectively locks the separation at the ramp-isolator junction which is otherwise free to move in the baseline intake. Strong three-dimensional (3D) behavior exists in the inlet-isolator flow at high back-pressures due to severe adverse pressure gradients and regions of flow separation around the shock trainches The highest level of unsteadiness in the intake was found to be around a normal shock train in the isolator. The oblique shock train showed mild low-frequency dynamics which can be linked to the large-scale separation at the isolator entrance. The flow choking near the intake exit triggers the unstart wave which propagates upstream. The unstart occurs through the development of a large-scale separation and boundary layer thickening at the ramp-isolator junction. The Notched intake displayed lower wave speed and a higher margin of unstart as compared to the baseline. The improvement in the understanding of the intake flowfield has laid down a path for future intake flow control efforts. The passive flow control device has displayed the potential to control SBLI and improve performance in supersonic intakes. The lessons learned in this study can be extended to other high-speed flows and applications during design and analysis.

Book Supersonic Inlet Investigation Volume 2 Air Induction System Dynamic Simulation Model

Download or read book Supersonic Inlet Investigation Volume 2 Air Induction System Dynamic Simulation Model written by and published by . This book was released on 1971 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: A one-dimensional mathematical dynamic simulation model for predicting the transient behavior of air induction systems for advanced tactical aircraft operating in the supersonic portion of the flight spectrum is discussed. As a part of the simulation model, control system logic is included to provide control system design criteria necessary to maintain air induction system response to selected input disturbances within prescribed limits. The model is applicable to both external and mixed compression inlets operating at supersonic conditions. The 'lumped parameter' concept is used in simulating the dynamic response of the subsonic duct downstream of the terminal shock, with the duct divided into three lumps.

Book Supersonic Inlet Investigation

Download or read book Supersonic Inlet Investigation written by T. W. Tsukahira and published by . This book was released on 1971 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reported herein are the results of an investigation whose primary objective was to develop design criteria and performance tradeoffs for supersonic inlets applicable to advanced tactical aircraft. The objective was accomplished by conducting analysis and wind tunnel tests. The baseline models included a two-dimensional external compression inlet, a two-dimensional mixed compression inlet, and a half-axisymmetric external compression inlet. Alternate configurations for the external compression baseline inlets in the AEDC PWT-4T and VKF-A wind tunnels, respectively. The inlets were tested both isolated and in a non-uniform flow field, the later representing partial simulation of a vehicle flow field. Inlet steady state performance was characterized in terms of pressure recovery, pressure distortion, and turbulence levels at a simulated compressor face and immediately downstream of the inlet throat. In addition, detailed analysis and correlation of data obtained with high response dynamic instrumentation were made.