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A Compact Thrust Augmenting Ejector Experiment
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Book Synopsis A Compact Thrust Augmenting Ejector Experiment by : Richard B. Fancher
Download or read book A Compact Thrust Augmenting Ejector Experiment written by Richard B. Fancher and published by . This book was released on 1970 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report briefly reviews the potential momentum thrust performance of ejectors. In addition to thrust performance, an ejector's utility to a V/STOL propulsion system is determined by several other factors including ejector size and airducting requirements. A survey of previous ejector experimental results are presented for ejectors with inlet area ratios in the neighborhood of 15 to 20. A compact two-dimensional ejector experiment with an inlet area ratio of 19 is described. This ejector with a 1.9 area ratio exit diffuser achieved a thrust augmentation ratio of 1.71 and 1.78 for an ejector length to minimum channel width ratio of 3.5 and 5.1 respectively. It is believed that improvements in primary injection techniques were responsible for this favorable thrust performance. (Author).
Book Synopsis Experimental Investigation of a Thrust Augmenting Ejector by : Hidayat Wiradimadja
Download or read book Experimental Investigation of a Thrust Augmenting Ejector written by Hidayat Wiradimadja and published by . This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ejector is basically a jet pump in which the kinetic energy of the jet is made to impart motion to the fluid surrounding it. During this process, in a well design system, the ejector as a whole experiences a thrust much higher than that of the jet alone. In principle, an ejector is nothing but a jet surrounded by a shroud. This investigation concerns the performance of a two- dimensional ejector with its primary jet excited by a novel method. A constant area duct was used in this experiment. The velocity of the jet at the exit was subsonic. Maximum thrust was obtained when the ejector to jet exit area ratio was about 35. Under this condition a thrust augmentation ratio of 1.65 was achieved, with the jet excited at 20 Hz, whereas without excitation it was only 1.40. The mixing characteristics of the jet under excitation was examined using flow visualization techniques. Smoke filaments illuminated by a sheet of powerful light and schlieren optics with the jet heated were used. Excitation of the jet was found to generate large vortex-like flow structures which might be responsible for enhanced mixing. These vortices extended to considerable distances on both sides of the jet.
Book Synopsis Low Area Ratio Thrust Augmenting Ejectors by : Richard B. Fancher
Download or read book Low Area Ratio Thrust Augmenting Ejectors written by Richard B. Fancher and published by . This book was released on 1971 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thrust augmentation, lift augmentation and noise reduction characteristics of compact ejectors make them potentially attractive for propulsion lift systems, although in the past poor thrust augmentation results have negated the other benefits. A synthesis of an ejector's internal flow phenomena developed in this paper indicates that improved mixing and diffusion can significantly increase thrust augmentation. A companion ejector experiment designed for rapid mixing confirms the model's augmentation predictions and shows reasonable agreement with other flow characteristics. (Author).
Book Synopsis Workshop on Thrust Augmenting Ejectors by :
Download or read book Workshop on Thrust Augmenting Ejectors written by and published by . This book was released on 1979 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thrust Augmentation Study of High Performance Ejectors by : John E. Minardi
Download or read book Thrust Augmentation Study of High Performance Ejectors written by John E. Minardi and published by . This book was released on 1983 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique is developed for determining a representative value of the maximum efficiency that can be achieved with high performance ejectors when operating on the supersonic solution branch of an ejector. These efficiencies are used to calculate thrust augmentation for an ejector over a wide range of parameters including operation with a hypothetical engine. Reasonable values of thrust augmentation can be achieved at low subsonic flight mach numbers. However, at flight Mach numbers near one, little or not thrust augmentation was found. At supersonic flight Mach numbers, thrust augmentation was achieved. Basic studies indicated that the effects of temperature was opposite at subsonic and supersonic flight Mach numbers. Thrust augmentation decreased with increasing temperature at subsonic Mach number sand increased with increasing temperature at supersonic Mach numbers.
Book Synopsis V-STOL Ejector Short Diffuser Study by : R. M. O'Donnell
Download or read book V-STOL Ejector Short Diffuser Study written by R. M. O'Donnell and published by . This book was released on 1976 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of thrust augmenting ejectors has produced ejector/diffuser configurations capable of achieving the high levels of thrust augmentation necessary for VTOL aircraft propulsion requirements. Experimental testing has shown that thrust augmenting ejectors can be made more compact by reducing diffuser length with active diffusion boundary layer control employing the Antiseparation Tailored Contour (ATC). Thrust augmentation and internal flow measurements were determined in compact high performance thrust augmentors with various length diffusers. The short ATC/diffusers tested showed significant improvements when compared to previous ejector diffusers. Measured thrust augmentation ratios with an optimum short ATC/diffuser were 10% greater than those with an equivalent straight wall diffuser. Length reductions of 36% were indicated for nominal augmentation ratios of 1.7. The important factors which influence the design and operation of compact thrust augmentor ejector/diffusers have been defined. (Author).
Book Synopsis Thrust Augmenting Ejectors by : Morton Alperin
Download or read book Thrust Augmenting Ejectors written by Morton Alperin and published by . This book was released on 1981 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: A discussion of the development of the compact jet-diffuser ejectors utilized for hovering and low speed flight propulsion has been presented. This is followed by a description of ideal ejector performance as derived from a compressible flow theory, over the range of flight speeds from zero to supersonic speed. These analyses introduced the concepts of ejector configuration optimization and the validity of the so-called 'second solution' to the mixing problem, wherein the flow after complete mixing is supersonic. The ideal performance of thrust augmenting ejectors designed under this 'second solution' has been shown to be far superior to those designed by conventional methods. The ability of properly designed ejectors to utilize the thermal energy of injected gas for the production of useful energy has also been described. Finally, the influence of major losses has been discussed, including means for avoiding excessive performance degradation by proper optimization of the geometry of the ejector in view of these losses.
Book Synopsis Experimental Investigation of Thrust Augmenting Ejectors Using Vane Excited Primary Jets by :
Download or read book Experimental Investigation of Thrust Augmenting Ejectors Using Vane Excited Primary Jets written by and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation has been conducted to evaluate the entrainment characteristics of a thrust augmenting ejector, with a small, oscillating airfoil inserted in the potential core of the primary jet. Velocity distributions were measured across the width of the jet, at downstream distances of 20 and 40 nozzle widths, with the jet exhausting into still air and with the jet exhausting into an instrumented ejector shroud for the following range of parameters: Pressure ratio 1.137 and 1.268, amplitude of oscillation 2.6 deg and 6.9 deg zero-to-peak frequency of oscillation 0, 20, 40 and 60 Hz. Static pressure distributions were measured within the shroud when the jector was installed. The results amplify previously conducted studies. Jet spreading and entrainment appear to increase with increasing amplitude and frequency of oscillation and to decrease with increasing nozzle pressure ratio. (Author).
Book Synopsis A Theoretical Study of Two Stage Thrust Augmenting Ejectors by : A. M. Abdel-Fattah
Download or read book A Theoretical Study of Two Stage Thrust Augmenting Ejectors written by A. M. Abdel-Fattah and published by . This book was released on 1984 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of theoretical assessment of two stage thrust augmenting ejectors are presented and compared with those of single stage ejectors. The mixing ducts were of constant cross sectional area, the flows at the inlet and exit planes of each stage were assumed to be uniform, and friction effects were ignored. It was found that staging the ejector increases thrust augmentation at all primary jet stagnation pressures, but is more effective in the low pressure range and with high ejector area ratios for any gas combination. With a Hot Rocket-Air combination, the benefit of staging is much less than with an unheated Air-Air combination, and does not appear to be of practical use.
Book Synopsis Experimental Investigation of Thrust Augmenting Ejectors Using Vane Excited Primary Jets by : Thomas Robert McClellan
Download or read book Experimental Investigation of Thrust Augmenting Ejectors Using Vane Excited Primary Jets written by Thomas Robert McClellan and published by . This book was released on 1982 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation has been conducted to evaluate the entrainment characteristics of a thrust augmenting ejector, with a small, oscillating airfoil inserted in the potential core of the primary jet. Velocity distributions were measured across the width of the jet, at downstream distances of 20 and 40 nozzle widths, with the jet exhausting into still air and with the jet exhausting into an instrumented ejector shroud for the following range of parameters: Pressure ratio 1.137 and 1.268, amplitude of oscillation 2.6 deg and 6.9 deg zero-to-peak frequency of oscillation 0, 20, 40 and 60 Hz. Static pressure distributions were measured within the shroud when the jector was installed. The results amplify previously conducted studies. Jet spreading and entrainment appear to increase with increasing amplitude and frequency of oscillation and to decrease with increasing nozzle pressure ratio. (Author).
Book Synopsis An Experimental Study of Thrust Augmenting Ejectors by :
Download or read book An Experimental Study of Thrust Augmenting Ejectors written by and published by . This book was released on 1983 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: An automated thrust augmentation data acquisition facility was designed and constructed. The facility provides the capability of measuring thrust augmentation ratio and mass flow augmentation ratio. A three dimensional graphics plot of exit flow is provided for flow analysis. Tests were conducted on a 4.4 in. diameter circular ejector, with eight primary nozzles mounted symmetrically along the perimeter of the inlet. A fixed ejector geometry was used. The ratio of mixing chamber area to diffuser exit area was 1.88. The fluid injection angle, measured from a line perpendicular to the ejector centerline, was varied and the thrust augmentation and mass flow augmentation ratios calculated. Both thrust augmentation and mass flow augmentation increased with fluid injection angle to the stall point where both decreased. Axial flow symmetry of primary air was found to affect stall along diffuser walls.
Book Synopsis Experimental Investigation of Thrust Augmenting Ejector Flows by : L. Bernal
Download or read book Experimental Investigation of Thrust Augmenting Ejector Flows written by L. Bernal and published by . This book was released on 1982 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of two investigations, one recently completed on pulsatile ejector flows and the second currently in progress on a two-dimensional ejector configuration are presented. The objective of these investigations is to determine the role of entrained fluid and its mixing with the primary jet on ejector performance. Results will also be presented on the effects of entrance geometry on ejector entrainment and thrust augmentation.
Book Synopsis An Experimental Study of a Pulsed Jet Ejector by : Isaac M. Choutapalli
Download or read book An Experimental Study of a Pulsed Jet Ejector written by Isaac M. Choutapalli and published by . This book was released on 2007 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first objective was addressed by carrying out direct thrust measurements on the free steady jet, free pulsed jet and the pulsed jet ejector configurations. Within the range of parameters investigated, it has been demonstrated conclusively that for an incompressible pulsed jet (Mj = 0.30) operating at a Strouhal number of around 0.1, thrust augmentation values as high as 1.9 can be obtained with a compact ejector (L/ D ≈ 3) at an area ratio (ejector inlet area/primary nozzle exit area) of about 11.0.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720364979 Total Pages :30 pages Book Rating :4.3/5 (649 download)
Book Synopsis A Simple Model of Pulsed Ejector Thrust Augmentation by : National Aeronautics and Space Administration (NASA)
Download or read book A Simple Model of Pulsed Ejector Thrust Augmentation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-29 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple model of thrust augmentation from a pulsed source is described. In the model it is assumed that the flow into the ejector is quasi-steady, and can be calculated using potential flow techniques. The velocity of the flow is related to the speed of the starting vortex ring formed by the jet. The vortex ring properties are obtained from the slug model, knowing the jet diameter, speed and slug length. The model, when combined with experimental results, predicts an optimum ejector radius for thrust augmentation. Data on pulsed ejector performance for comparison with the model was obtained using a shrouded Hartmann-Sprenger tube as the pulsed jet source. A statistical experiment, in which ejector length, diameter, and nose radius were independent parameters, was performed at four different frequencies. These frequencies corresponded to four different slug length to diameter ratios, two below cut-off, and two above. Comparison of the model with the experimental data showed reasonable agreement. Maximum pulsed thrust augmentation is shown to occur for a pulsed source with slug length to diameter ratio equal to the cut-off value.Wilson, Jack and Deloof, Richard L. (Technical Monitor)Glenn Research CenterTHRUST AUGMENTATION; MATHEMATICAL MODELS; FLOW VELOCITY; HARTMANN-SPRENGER TUBES; VORTEX RINGS; PULSED JET ENGINES; EJECTORS
Book Synopsis Experiments on High Speed Ejectors by :
Download or read book Experiments on High Speed Ejectors written by and published by . This book was released on 198? with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies were conducted to investigate the flow and the performance of thrust augmenting ejectors for flight mach numbers in the range of 0.5 to 0.8, primary air stagnation pressures up to 107 psig (738 kPa), and primary air stagnation temperatures up to 1250 F (677 C). The experiment verified the existence of the second solution ejector flow, where the flow after complete mixing is supersonic. Thrust augmentation in excess of 1.2 was demonstrated for both hot and cold primary jets. The experimental ejector performed better than the corresponding theoretical optimal first solution ejector, where the mixed flow is subsonic. Further studies are required to realize the full potential of the second solution ejector. Keywords: Thrust augmentation; Jet mixing flow; Supersonic flow; Subsonic flight; Transonic flight. (EDC).
Book Synopsis Inlet and Diffuser Effects on Thrust Augmenting Ejectors by : S. G. Reznick
Download or read book Inlet and Diffuser Effects on Thrust Augmenting Ejectors written by S. G. Reznick and published by . This book was released on 1982 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effects of primary jet inlet nozzle configuration and diffuser geometry on the thrust augmentation of circular and rectangular ejectors are investigated in an experimental study. The rectangular ejector inlet nozzle configurations consist of either one, two, or three slot nozzles. The circular ejector inlet nozzles consist of slot nozzles placed either across the inlet or around the inlet periphery. Diffuser geometry is varied primarily by changing the diffuser area ratio. Effect on thrust performance of the primary flow injection angle relative to the inlet walls is investigated. Effects of side-wall, end-wall, and diffuser blowing on thrust performance and diffuser stall also are considered.
Book Synopsis Study of Three-Dimensional Thrust-Augmenting Ejectors by : Ramesh K. Agarwal
Download or read book Study of Three-Dimensional Thrust-Augmenting Ejectors written by Ramesh K. Agarwal and published by . This book was released on 1982 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theory is presented for the prediction of thrust augmentation characteristics of a three-dimensional ejector configuration in which a series of rectangular-hypermixing nozzles pumps the secondary air in a constant-area or slowly diverging channel. Based on the theory, a computer program is developed which requires the ejector design parameters, the empirical constants in the eddy viscosity model, and the nozzle pressure ratio as input and calculates the entrained secondary mass flow, the secondary and exit velocities, the net thrust and the thrust augmentation ratio. Good agreement is found between the theoretical prediction and the experimental data.
