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Journal ArticleDOI

Supersonic-ejector characteristics using a Petal nozzle

01 Sep 1994-Journal of Propulsion and Power (American Institute of Aeronautics and Astronautics (AIAA))-Vol. 10, Iss: 5, pp 742-744
TL;DR: In this paper, two nozzles, Conical or Petal, may be attached to the secondary flow settling chamber, which is annular and coaxial with the primary air line, and two venturimeters, one on either side of the secondary settling chamber for measurement of secondary mass flow rate; four bellmouths to facilitate proper entry of secondary entrained flow; and ejector shroud.
Abstract: which either of the two nozzles, Conical or Petal, may be attached; 2) the secondary flow settling chamber which is annular and coaxial with the primary air line; 3) two venturimeters, one on either side of the secondary settling chamber, for measurement of secondary mass flow rate; 4) bellmouths to facilitate proper entry of the secondary entrained flow; and 5) ejector shroud. Air was used as the working gas for the primary stream. Both nozzles have a throat diameter of 22 mm and area ratio of 1.34 (design pressure ratio = 5:1). Exit Mach number is about 1.7. All tests were done using constant ejector area ratio. Cylindrical acrylic tubes of L/D varying from 4.35 to 0.87 were used for the ejector shroud. Two types of tests were conducted: 1) with no secondary flow and 2) with secondary flow. For tests with no secondary flow, the venturimeters were replaced by end-plates, thus sealing the secondary flow settling chamber from the ambient.
Citations
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Journal ArticleDOI
TL;DR: In this article, two supersonic nozzles Tip Ring Supersonic Nozzle and Elliptic Sharp Tipped Shallow (ESTS) Lobed Nozzle have been developed to enhance mixing at high speeds.

63 citations

Journal ArticleDOI
TL;DR: In this paper, the authors applied a petal nozzle to enhance the performance of a steam-jet refrigeration system and investigated the behavior and characteristics of the petal-filled ejector under various operating conditions.

62 citations

Patent
31 May 2007
TL;DR: In this article, a vortex tube is used to deliver cold air into the turbocharger compressor where it may be used to cool the impeller, accelerate the turbine speed, and favorably shift the compressor surge line at low speeds and high loads.
Abstract: The present invention relates to a turbocharged internal combustion engine (ICE) system having fast response to increased power demand and reduced response time lag. The system includes a vortex tube for delivering cold air into the turbocharger compressor where it may be used to cool the impeller, and/or accelerate the impeller rotational speed, and/or favorably shift the compressor surge line at low speeds and high loads. Cold air from the vortex tube may be also used to operate an ejector pump in the intake duct which further compresses intake air and increases engine charge weight during periods of high power demand. In addition to increasing engine output power, delivery of cold air into engine intake also reduces engine pre-ignition (knocking) thereby reducing emissions. The invention also relates to a method for operating a turbocharged internal combustion engine.

53 citations

Journal ArticleDOI
TL;DR: In this article, an analytical model of a supersonic/subsonic, constant-area ejector whose exit flow is not uniformly mixed is presented, where the primary and secondary streams, separated by the dividing streamline, are treated as quasi-one-dim ensional.
Abstract: This article presents an analytical model of a supersonic/subsonic, constant-area ejector whose exit flow is not uniformly mixed. The primary and secondary streams, separated by the dividing streamline, are treated as quasi-one-dim ensional. The shear stress on the dividing streamline, the resulting heat transfer, and the wall stresses are applied artificially on the streams. Axisymmetric and two-dimensional configurations are considered. The model predicts that the axisymmetric ejector provides better thrust augmentation than the two-dimensional one, the latter suffering from higher skin-friction losses. Thrust increases with ejector length, but at a diminishing rate. For all configurations, thrust augmentation decreases with flight Mach number and becomes zero at a flight Mach number of about 0.7. Increasing the primary-to-secondary area ratio has a minimal effect on thrust. The results compare favorably with available experimental data on pressure distributions and mass-flow ratios. Nomenclature A = cross-sectional area a = speed of sound b = ejector radius (A/5) or half-height (two dimensional) cp = specific heat at constant pressure H = total enthalpy h = static enthalpy / = length scale, Eq. (11) M - Mach number Mc = cpnvective Mach number m = mass flux p = pressure q = heat transfer R = gas constant r = velocity ratio, U^/U^ $ = entropy flux 5- = entropy T = temperature U = velocity x = streamwise coordinate y = transverse coordinate y = specific-heat ratio A£7 = tfcol - t/oc* 6W = shear-layer vorticity thickness 77 = density ratio, IJL = viscosity p = density T = shear stress

38 citations

Patent
19 Jan 2007
TL;DR: In this article, a supercharged internal combustion engine system is described, where during periods of high power demand the weight of combustion chamber charge is increased by cooling intake air in a vortex tube operated by high-pressure air from a storage tank.
Abstract: A supercharged internal combustion engine system wherein during periods of high power demand the weight of combustion chamber charge is increased by cooling intake air in a vortex tube operated by high-pressure air from a storage tank. In addition to increasing engine output power, cold air intake also reduces engine pre-ignition (knocking) thereby reducing emissions. Included are means for sensing engine power demand and controlling the supercharging action. Output of the vortex tube may be also used to operate an ejector pump which further compresses intake air and increases charge weight. During periods of natural aspiration the ejector pump can be by-passed to reduce flow impedance. Effective supercharging is achieved even at low engine speeds. One of the objects of the invention is to obtain more power from small displacement ICE and thus providing automotive vehicles with sufficient acceleration in addition to good fuel economy. Another object of the invention is to enhance turbocharged engines and reduce their response lag.

30 citations

References
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Journal ArticleDOI
TL;DR: In this article, Schlieren photographs of the flow field along with hot-wire measurements in the jet were obtained at different pressure ratios and it was shown that the self-excitation helps to induce large scale vortical motions in a converging rectangular nozzle.

164 citations

Proceedings ArticleDOI
16 Jun 1986
TL;DR: In this article, a large scale axial vorticity in the mixing duct is generated by the augmentation of a primary ejector with a large number of augmentation lobes.
Abstract: Forced mixer lobes in augmentor primary ejectors obtain a 100-percent increase in pumping over conventional design, together with nearly complete mixing in very short mixing ducts, through the generation of large scale axial vorticity in the mixing duct. The vorticity causes rapid mixing of the primary and secondary flows with low losses; since mixing length is minimized, wall friction losses are reduced, allowing more secondary flow to be pumped for a given total pressure in the primary flow. Analytical results are presented that are judged to have significant implications for future ejector test work.

101 citations

Proceedings ArticleDOI
24 Mar 1987

95 citations

Journal ArticleDOI
TL;DR: In this article, a convergent-divergent primary lobed nozzles were designed and tested at high-temperature, supersonic primary flow regime to evaluate mixer ejector performance.
Abstract: The intent of this article is to describe recent experimental findings relative to supersonic nozzle mixer ejector performance. Such ejectors are a candidate means to reduce jet noise of commercial supersonic aircraft during takeoff and landing. The mixer ejector concept involves the introduction of an array of large-scale, low-intensity streamwise vortices into the downstream mixing duct, which enhances mixing through an inviscid stirring process. This results in increased ejector pumping performance and more completely mixed flows exiting the ejector shroud. Past experimental and analytical investigations of mixer ejectors have been confined to low-speed subsonic flows, and low primary temperatures (less than 2000°F). In this flow regime, ejector static pumping benefits of over 100% were achieved relative to conventional ejector designs. The goal of the present study was to evaluate mixer ejector performance in the high-temperature, supersonic primary flow regime. A convergentdivergent primary lobed nozzle (i.e., mixer nozzle) was designed and tested at choked pressure ratios in an ejector. Ejector pumping and exit plane mixing were measured for the mixer ejector and a conventional slot nozzle ejector. The two configurations were operated at a nozzle exit Mach number of 1.5 (nozzle pressure ratio = 3.4), a primary fluid total temperature of 1000°F, and a simulated forward flight Mach number of 0.1. Results indicate that properly designed lobed nozzles can increase supersonic ejector pumping by over 15%, relative to conventional slot primary nozzles.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented a summary of the radial planarity in terms of phase and amplitude of the probe readings from two of the rakes, 180° apart, at the engine IGV plane.
Abstract: Steady-state distortion levels produced during full scale PG operation as evaluated in terms of IDC (circumferential) and IDR (radial) distortion parameters were generally less 0.02 and nominally 0.01 or less as previously realized in the model test. Figure 10 summarizes the circumferential planarity in terms of phase and amplitude. The probe readings from two of the rakes, 180° apart, at the engine IGV plane were averaged to obtain these summary results. Such a comparison indicates excellent circumferential planarity over the complete range of the test data. A similar summary of radial planarity characteristics is presented in Fig. 11. In this case, all the probe readings from 2 selected radial immersions were averaged. Radial immersion B is the tip and D is the hub ring. The hub ring probes had the most deviation from those in any of the other rings, thus the results of Fig. 11 represent the "worst case."

70 citations