Download or read book Entrainment and Mixing in Thrust Augmenting Ejectors written by L. Bernal and published by . This book was released on 1982 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been performed with subsonic and underexpanded choked two-dimensional primary nozzle ejector flow system without diffusion to evaluate the role of entrainment and mixing in thrust augmentation. Two-component Laser Doppler velocity measurements (mean and fluctuating values), thrust measurements, ejector shroud surface pressure measurements and flow visualization were used to determine the evolution of the velocity profiles and their relationship to the ejector performance.
Download or read book An Experimental Investigation of Two Dimensional Thrust Augmenting Ejectors written by L. Bernal and published by . This book was released on 1984 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were performed with subsonic and underexpanded choked two-dimensional primary nozzle ejector flow systems without diffusion to evaluate the role of entrainment and mixing in thrust augmentation. Two-component Laser Doppler velocity measurements (mean and fluctuating values), thrust measurements, ejector shroud surface pressure measurements and flow visualization were used to determine the evolution of the velocity profiles and their relationship to the ejector performance. Key findings include: (1) Primary jet growth is significantly altered by the ejector shroud. (2) Primary jet turbulent characteristics when normalized with the local mean centerline velocity are in agreement with those for the free-jet. (3) In the neighborhood of the ejector shroud the flow field can be classified into two regions--the potential flow region and the region close to the ejector exit which is dominated by the turbulent transport. (4) Pressure recovery is very sharp in the first region and is more gradual in the region close to the ejector exit. The investigation is continuing toward the near-term objectives of obtaining measurements within diffused flow and with heated primary air. This volume emphasizes the laser doppler velocimetry developed especially for this program. Part II (AD-A154 083) presents detailed cold flow measurements along with preliminary primary hot flow data.
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:
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.
Download or read book Applicability of Thrust Augmenting Ejectors in a Supersonic Cruise Configuration written by Wendell S. Hertzelle and published by . This book was released on 1997-04-01 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thrust augmenting ejectors were analyzed by the author in an attempt to see if they could be used to provide a significant thrust increase over the baseline thrust of a primary core. This was done for the purpose of determining if leaving the ejectors open in the cruise configuration of the High Speed Civil Transport would lead to a thrust increase that would at least offset the weight of the ejectors themselves. If this was found to be true then the fuel economy of the HSCT might be improved by leaving them open and not closing them during cruise. In analyzing the ejectors, no assumptions were made regarding inlet nor outlet configurations, so an attempt was made to find the point of optimal thrust augmentation by varying secondary stream bypass Mach number and the amount of flow entrainment. Two solutions were found to each mixing scenario, one subsonic and the other supersonic. These two solutions were each analyzed and ones not satisfying the Second Law of Thermodynamics were eliminated. Analytic diffuser and bleed losses were also explored in the analysis of the ejector flow. Within the limitations of the assumptions discussed in this paper, appreciable thrust augmentations have been discovered over a large range of bypass Mach numbers and entrained mass flows. This lead the author to the conclusion that ejectors warrant further research beyond a first order analysis, and serious thought should be put into leaving them open in cruise.
Download or read book Annular jet Ejectors written by Elliott G. Reid and published by . This book was released on 1947 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings written by R. P. Braden and published by . This book was released on 1982 with total page 1094 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book An Experimental Study of a Three dimensional Thrust Augmenting Ejector Using Laser Doppler Velocimetry written by Bruce Lowell Storms and published by . This book was released on 1989 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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).
Download or read book Static Thrust Augmentation of a Rocket ejector System with a Heated Supersonic Primary Jet written by Albert J. Simonson and published by . This book was released on 1962 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: "An investigation was conducted in order to evaluate the static thrust augmentation attainable through the use of a rocket-ejector system with a heated supersonic primary jet. This system consisted of a cylindrical mixing tube in conjunction with a supersonic nozzle having an expansion ratio of 15 to 1. A hydrogen peroxide gas generator was used to provide heated nozzle flow. An ejector with a bellmouthed inlet provided thrust augmentation up to about 18 percent of the primary rocket thrust, whereas the use of a blunt-lip inlet with elliptical profile provided augmentation up to 9 percent. Axial withdrawal of the rocket nozzle from the ejector provided small gains in thrust augmentation."--P.[1]
Download or read book Performance of Thrust Augmenting Ejectors written by Paul Allen Van and published by . This book was released on 1971 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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).
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.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Ejector Thrust Augmentation Study Mass Entrainment of Axisymmetric and Rectangular Free Jets written by William Peschke and published by . This book was released on 1973 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation has been performed to evaluate the entrainment characteristics of nonaxisymmetric (rectangular) primary nozzles for ejector into air application. Data are presented which show the variation in mass entrainment rates of various nozzles as related to isentropic nozzle exit velocity and distance downstream of the nozzle exit. The entrained mass flow is determined by direct measurement for an axisymmetric nozzle and for rectangular nozzles with aspect ratios of 1, 10, 25, and 50. Most of the data presented are for isentropic nozzle exit Mach numbers between about 0.08 and 0.3. Some data are presented for Mach numbers up to about 0.52. All data are for nozzles exhausting into a quicsent atmosphere. (Modified author abstract).
