Showing papers on "Nozzle published in 1995"

Generating Particle Beams of Controlled Dimensions and Divergence: I. Theory of Particle Motion in Aerodynamic Lenses and Nozzle Expansions

Abstract: A particle beam is produced when a particle-laden gas expands through a nozzle into a vacuum. This work discusses the theoretical basis of a novel method for producing highly collimated and tightly focused particle beams. The approach is to pass the particle-laden gas through a series of axisymmetric contractions and enlargements (so-called aerodynamic lenses) before the nozzle expansion. Particles are moved closer to the axis by a lens if the particle sizes are less than a critical value and particles can be confined very closely to the axis by using multiple lenses in series. Since particles close to the axis experience small radial drag forces, they stay close to the axis during nozzle expansion and therefore form a narrow particle beam downstream. The major effects that limit the minimum beam width are Brownian motion and lift forces on particles during the nozzle expansion. Simple theoretical models are developed in this work to estimate the minimum particle beam width set by these effects. While the...

Fluid drop ejector and method

Abstract: An improved fluid drop ejector is disclosed which includes one wall including a thin elastic membrane having an orifice defining a nozzle and elements responsive to electrical signals for deflecting the membrane to eject drops of fluid from the nozzle.

Generating Particle Beams of Controlled Dimensions and Divergence: II. Experimental Evaluation of Particle Motion in Aerodynamic Lenses and Nozzle Expansions

Abstract: A particle-beam-forming apparatus for producing narrow particle beams was developed based on the theory discussed in paper I of this series. It consists of a variable number of aerodynamic lenses (short capillaries and/or thin-plate orifices with diameters ranging from 3.5 to 7.0 mm) followed by an accelerating nozzle (3 mm). It was evaluated using monodisperse DOS and NaCl particles (0.02–0.24 μm) at upstream pressures on the order of 1 torr. The particle beams produced by the lens-nozzle system were focused through a skimmer (1 mm) into a high vacuum chamber (10−4–10−5 torr) where the beam widths, velocities and transport efficiencies were measured. The experiments showed that as more lenses were added the particle beam widths were reduced asymptotically to the minimum values. For spherical particles (DOS) these minimum values are in good agreement with the Brownian limit derived in paper I. For nonspherical particles (NaCl) these minimum widths are much larger than the Brownian limit, indicating that b...

Confined and Submerged Liquid Jet Impingement Heat Transfer

Abstract: The local heat transfer from a small heat source to a normally impinging, axisymmetric, and submerged liquid jet, in confined and unconfined configurations, was experimentally investigated. A single jet of FC-77 issuing from a round nozzle impinged onto a square foil heater, which dissipated a constant heat flux. The nozzle and the heat source were both mounted in large round plates to ensure axisymmetric radial outflow of the spent fluid. The local surface temperature of the heat source was measured at different radial locations (r/d) from the center of the jet in fine increments. Results for the local heat transfer coefficient distribution at the heat source are presented as functions of nozzle diameter (0.79 ≤ d ≤ 6.35 mm), Reynolds number (4000 to 23,000), and nozzle-to-heat source spacing (1 ≤ Z/d ≤ 14). Secondary peaks in the local heat transfer observed at r/d 2 were more pronounced at the smaller (confined) spacings and larger nozzle diameters for a given Reynolds number, and shifted radially outward from the stagnation point as the spacing increased. The secondary-peak magnitude increased with Reynolds number, and was higher than the stagnation value in some instances.

Ink jet recorder

Abstract: PURPOSE: To perform the high density disposition and high frequency response of nozzles by injecting the ink of an ink chamber from the nozzle by displacing the inserting part of a pressurizing member toward the nozzle. CONSTITUTION: A piezoelectric element 32 applied by a voltage is restricted for the deformation in the area fixed to a support plate 30, abruptly elongation deformed at the inserting part extended mainly into an ink chamber 23, and displaced at the end face toward a nozzle hole 27. The ink charged in the chamber 23 is so pressurized by the displacement as to be pressed by a piston, flown in a droplet state from the hole 27, and stuck on a record sheet. When the voltage is eliminated to individual electrodes 34, the element 32 is returned to the original state. At this time, negative pressure is generated in the chamber 23, and the ink is supplied to the chamber 23 via an ink manifold 29 and an ink supply port 22. With this structure, the high density disposition and high frequency response of the nozzles are performed.

Controlling PWA inkjet nozzle timing as a function of media speed

Abstract: A page-wide-array ("PWA") inkjet printer includes a printer element defining a printhead with thousands of nozzles spanning a pagewidth. A media sheet travels along a media path adjacent to the printhead to receive character or graphic markings. Typically, a media sheet accelerates from rest to a constant velocity. To optimize print speed nozzle timing is controlled to respond to changes in media velocity. Printing occurs while the media is accelerating and while traveling at a constant velocity. A sensor positioned in fixed relation to a PWA printer element detects the media's actual velocity. Actual velocity is fed back to a printhead controller which compares actual velocity to a rated constant velocity. If actual velocity is slower than the rated velocity, then nozzle timing is adjusted to be slower than a rated timing. If actual velocity is faster than rated velocity, then nozzle timing is adjusted to be faster than the rated timing.

Nanoparticle formation using a plasma expansion process

Abstract: We describe a process in which nanosize particles with u narrow size distribution are generated by expanding a thermal plasma carrying vapor-phase precursors through a nozzle. The plasma temperature and velocity profiles are characterized by enthalpy probe measurements. by calorimetric energy balances. and by a model of the nozzle flow. Aerosol samples are extracted from the flow downstream of the nozzle by means of a capillary probe interfaced to a two-stage ejection diluter. The diluted aerosol is directed to a scanning electrical mobility spectrometer (SEMS) which provides on-line size distributions down to particle diameters of 4 nmt. We have generated silicon, carbon, and silicon carbide particles with number mean diameters of about 10 not or less, and we have obtained some correlations between the product and the operating conditions. Inspection of the size distributions obtained in the experiments, together with the modeling results, suggests that under our conditions silicon carbide formation is initiated by nucleation of extremely small silicon particles from supersaturated silicon vapor, followed by chemical reactions at the particle surfaces involving carbon-containing species from the gas phase.

Cluster beam targets for laser plasma extreme ultraviolet and soft x-ray sources

Abstract: Method and apparatus for producing extreme ultra violet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (1011 -1012 watts/cm2) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10-30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle.

Numerical Study of Steady Turbulent Flow through Bifurcated Nozzles in Continuous Casting.

Abstract: Bifurcated nozzles are used in continuous casting of molten steel, where they influence the quality of the cast steel slabs. The present study performs two-dimensional (2-D) and three-dimensional (3-D) simulations of steady turbulent(K- e) flow in bifurcated nozzles, using a finite-element (FIDAP) model, which has been verified previously with water model experiments. The effects of nozzle design and casting process operating variables on the jet characteristics exiting the nozzle are investigated. The nozzle design parameters studied include the shape, angle, height, width, and thickness of the ports and the bottom geometry. The process operating practices include inlet velocity profile and angle as well as port curvature caused by erosion or inclusion buildup. Results show that the jet angle is controlled mainly by the port angle but is steeper with larger port area and thinner walls. The degree of swirl is increased by larger or rounder ports. The effective port area, where there is no recirculation, is increased by smaller or curved ports. Flow asymmetry is more severe with skewed or angled inlet conditions or unequal port sizes. Turbulence levels in the jet are higher with higher casting speed and smaller ports.

Characterization of d.c. plasma torch voltage fluctuations

Abstract: The arc root fluctuations at the anode-nozzle of a d.c. plasma spray torch with a special configuration of the electrodes allowing to work with the same gas flowrate with nozzle diameters ranging from 6 to 10 mm were systematically studied. The plasma gas was Ar/H2 (25 vol % H2), the current was varied between 200 and 600 A and the plasma gas flowrate between 24 and 80 slm. After 30–60 mn working the nozzle wall started to be sufficiently eroded to have a stagnant arc spot which lived until arcing created another one. It was shown that the life time of the upstream arc spots were 30–40 % longer than the downstream ones which could play an important role in the electrode erosion. Dimensional analysis allowed to find a relationship between the nozzle diameter D, the arc current I and gas flow rate G and the mean spot lifetime which is closely connected with the difference between D and the electrical diameter of the arc column. The comparison of voltage signal and light emission at a point of the plasma jet close to the nozzle exit on its axis allowed to determine the mean electrical field within the plasma column and the mean position of the arc root. The comparison with the electrode erosion area for well defined conditions showed a good correlation with the calculated arc root position.

Integrated power and cooling environmental control system

Abstract: An environmental control system has an air cycle machine that includes a compressor (38), a cooling turbine (34), a motor/generator (36), and a power turbine (40) all mounted on a single shaft (32). The power turbine receives bleed air from the aircraft's engine (12) and has a variable geometry inlet nozzle (42) that adjusts the air flow rate therethrough without significant throttling. Downstream of the nozzle the power turbine extracts the expansion energy from the bleed air while cooling it. This is used to drive the other components of the air cycle machine, and in particular the motor/generator which generates electricity.

Position-responsive control system and method for sprayer

Abstract: A flow rate and droplet size control system for a spray system including a spray liquid source, a pump, a spray liquid line and a nozzle assembly. The control system includes a setpoint conversion subroutine for independently controlling the flow rate and volume median droplet size setpoints. The control system also includes performance envelopes for various nozzle tips. An independent flow rate and droplet size control method is provided for use with the control system. A position-responsive control system receives information pertaining to the boundaries of spray zones and spray conditions, such as application rates and volume median droplet diameters associated with the spray zones. The position-responsive control system monitors the position of a spray vehicle, which can comprise a ground vehicle or an aircraft. The position-based control system changes the spray system operating conditions in response to the sprayer vehicle position. A position-based method of controlling the spray system utilizes the position-based control system.

Breakup Phenomena in Coaxial Airblast Atomizers

Abstract: The breakup of a liquid jet with length-to-diameter ratio of 22 surrounded by a coaxial flow of air has been examined by a combination of high-speed photography and phase-Doppler velocimetry. The air-to-liquid momentum and kinetic energy ratios, the Reynolds number of the coaxial water and air jet flows and the exit-plane Weber number have been varied over extensive ranges and the results examined in terms of the breakup length, frequency, droplet size distributions and velocity characteristics. The photographs reveal the deterministic nature of the liquid flow at Reynolds numbers which are sufficient to guarantee turbulent flow, with the formation of a wave-like structure for a short distance followed by the formation of a liquid cluster and subsequent breakup into ligaments and droplets, with the entire process repeated in a periodic manner. Attempts are made to relate the breakup length and the frequency of the process to the air-to-liquid momentum and energy ratios, the exit Weber number and the slip velocity between the two streams at the nozzle exit. The results confirm that the ratio of the frequencies of the wave-like structures and breakup decreased with the slip velocity between the two streams and asymptotically approached a value of around one for values higher than 150 m s -1 . The photographs indicate that the droplet sizes in the sprays are due mainly to disintegration of liquid clusters produced after the initial breakup of the liquid jet and the phase Doppler measurements confirm that most of the liquid remained close to the centreline, where the mean diameter reached a maximum and the slip velocity between the droplets and the air flow was low. An atomization model based on the value of the local Weber number on the centreline of the sprays is used to explain the size characteristics of the sprays. The atomization process was affected by the air-to-liquid momentum ratio at the nozzle exit, the annular width of the coaxial atomizer, the liquid-to-air density ratio, the surface tension and the kinematic viscosity and density of the air. The rate of spread of the sprays close to the nozzle reduced with increase of the air and liquid flowrates and was affected by the initial breakup of the liquid jet and the amplitude of the wave-like structure of the liquid jet during breakup rather than by the air flow turbulence.

Star combustor with dilution ports in can portions

Abstract: A generally annular combustor system has a chamber with an annular chamber portion and a plurality of can-like chamber portions protruding from the annular chamber portion. An external fuel/air premixer is associated with each can chamber portion to provide a mixture with a desired (generally lean) fuel/air ratio tangentially through the can sidewall. A first portion of the total compressed air flows to the premixers, a second portion enters the combustion chamber through ports which, for can chamber volumes sufficient for complete combustion, can be located in the can chamber portion proximate the connection between the can portion and the annular portion. The premixer associated with each can chamber portion preferably includes a venturi and a fuel nozzle for spraying liquid fuel or gas into the venturi inlet to provide a fully premixed fuel/air mixture. An auxiliary fuel nozzle can be positioned in the annular portion for selectively supplying fuel for reheat of the combustion gases, using the dilution air, to maintain combustor outlet temperature. The annular chamber portion advantageously can be nested between the compressor and turbine components of large axial flow-type gas turbines in retrofit applications.

Method and apparatus for machining material with a liquid-guided laser beam

Abstract: An arrangement for processing material with a liquid jet comprising a laser for emitting a laser beam. The arrangement includes a processing module having a nozzle duct connected to a liquid supply line for forming a liquid jet. The nozzle duct has an intake opening lying in an intake opening plane. An optical element couples the laser beam into the liquid jet, and the optical element of the laser beam is focused in a focusing point range and into the intake opening plane of the nozzle duct. The liquid supply line for the nozzle duct defines an area formed above the nozzle intake opening having a height dimensioned relative to the cross-sectional area of the intake opening such that the area above the nozzle intake opening does not include a liquid retaining chamber. The absence of the liquid retaining chamber producing a flow speed for the liquid in a focusing cone point range sufficiently high that, for a predetermined low radiation absorption coefficient for the liquid, the formation of a thermal lens in the liquid in the focusing cone point range is suppressed enough so that no portion of the radiation damages walls of the nozzle duct.

A valve-less planar pump isotropically etched in silicon

Abstract: The first valve-less diffuser fluid pump in silicon is presented. It consists of a planar double-chamber arrangement fabricated in a silicon wafer anodically bonded to a glass wafer. The pump uses fluid-directing diffuser - nozzle elements which have a depth of and a neck width of . The pump chamber diameter is 6 mm. Pump cavities and diffuser - nozzle elements are etched with an isotropic HNA silicon etch. Pumps with three different diffuser lengths are compared reaching a maximum pump capacity of and a maximum pump pressure of 1.7 m at a resonance frequency of 1318 Hz for methanol.

Bulkhead and fuel nozzle guide assembly for an annular combustion chamber

Abstract: An assembly of a bulkhead (48) and fuel nozzle guide (62) for a fuel nozzle (46) disposed in a combustion chamber (24) is disclosed. Various construction details which provide for convection cooling of the various components of the assembly are developed. In one detailed embodiment, the nozzle fuel guide (62) is spaced from the bulkhead (48) to form an annular gap (G1) which is divided by a heat shield (72) into annular orifices (108, 112) for supplying to cooling air passages (126, 128) bounded by the heat shield (72).

Validation of Multitemperature Nozzle Flow Code

Abstract: A computer code nozzle in n-temperatures (NOZNT), which calculates one-dimensional flows of partially dissociated and ionized air in an expanding nozzle, is tested against three existing sets of experimental data taken in arcjet wind tunnels. The code accounts for the differences among various temperatures, i.e., translational-rotational temperature, vibrational temperatures of individual molecular species, and electron-electronic temperature, and the effects of impurities. The experimental data considered are (1) the spectroscopic emission data; (2) electron beam data on vibrational temperature; and (3) mass-spectrometric species concentration data. It is shown that the impurities are inconsequential for the arcjet flows, and the NOZNT code is validated by numerically reproducing the experimental data.

Aircraft thrust vectoring system

Abstract: A thrust vectoring system comprising a working fluid source mounted to an aircraft, and a vectoring nozzle connected to the working fluid source which has an extendable conduit defining a passage from an inlet to an outlet The passage is adjustable so that the direction of the working fluid exiting the outlet is different than the working fluid entering the inlet when the conduit of the vectoring nozzle is extended This conduit provides a way to change the direction of working fluid exiting the nozzle and correspondingly change the thrust vector of the aircraft A directing member such as a guide vane or door is mounted to the conduit adjacent the outlet to further direct the working fluid exiting the outlet Directing members provide a way to refine the thrust vector without changing the extension of the segmented conduit Another aspect of the present invention is to provide an adapter to connect the vectoring nozzle to a working fluid source with an annular outlet This adapter uses an asymmetric structure to minimize flow separation

Deposition chamber for improved deposition thickness uniformity

Abstract: An improved deposition chamber (2) includes a housing (4) defining a vacuum chamber (18) which houses a substrate support (14). A set of first nozzles (34) have orifices (38) opening into the vacuum chamber in a circumferential pattern spaced apart from and generally overlying the periphery (40) of the substrate support. One or more seconds nozzle (56, 56a), positioned centrally above the substrate support, inject process gases into the vacuum chamber to improve deposition thickness uniformity. Deposition thickness uniformity is also improved by ensuring that the process gases are supplied to the first nozzles at the same pressure. If needed, enhanced cleaning of the nozzles can be achieved by slowly drawing a cleaning gas from within the vacuum chamber in a reverse flow direction through the nozzles using a vacuum pump (84).

Ink jet recording apparatus.

Abstract: An inkjet recording apparatus comprises an inkjet head (10) having for each of one or more nozzles (4) an ink passage (7, 6) in communication with the nozzle (4) and an electrostatic actuator. The actuator includes a diaphragm (5) provided at one part (6) of the ink passage, a nozzle electrode (21) provided in opposition to the diaphragm (5) with a gap (G) in between and a vibration chamber (9) having upper and lower walls of which one wall is formed by one part of said diaphragm (5), while said nozzle electrode is attached to the other wall. The diaphragm constitutes one and the nozzle electrode (21) the other plate of a capacitor. Drive means selectively charge and discharge each actuator such as to displace its diaphragm (5) by electrostatic force, thereby to eject ink droplets from said one or more nozzles. Vibration chamber (9) is sealed to be airtight. Its volume V is such that the ratio between this volume V and the volume DELTA V displaced by the diaphragm is within the range 2

Recirculating type cleaner

Abstract: In a recirculating type cleaner, a jet nozzle is provided within a dust collecting head formed in the bottom face of the housing, the after-flow air from the suction fan is supplied through a recirculating tube to the jet nozzle. In the after-flow of the fan is provided a branch valve which is controlled by a controller to set the air recircuration ratio at a desired value suitable for any cleaning mode.

System for generating hydrogen

Abstract: A process and apparatus are disclosed for generating hydrogen gas from a charge of fuel selected from the group consisting of lithium and alloys of lithium and aluminum. The charge of fuel is placed into an enclosed vessel, then heated until it is molten. A reactant consisting of water is introduced into the vessel, as by spraying from a nozzle, for reaction with the charge of fuel resulting in the production of hydrogen gas and heat which are withdrawn from the vessel. Prior to initiation of the process, an inert gas atmosphere, such as argon, may be imparted to the interior of the vessel. A sufficiently large mass flow of the reactant through the nozzle is maintained to assure that there be no diminution of flow resulting from the formation on the nozzle of fuel and chemical compounds of the fuel. Optimum charges of the fuel are application specific and the ranges of the constituents are dependent upon the particular use of the system. The process and apparatus of the invention may be incorporated into a Rankine cycle engine or into a hydrogen oxygen fuel cell system.

Floor nozzle for vacuum cleaners

Abstract: A floor nozzle for vacuum cleaners comprises a housing and two suction channels, separated by an intermediate strip, arranged in the bottom plate thereof and extending transversely to the direction of movement the intermediate strip being designed as a rigid plow strip arranged between a front and a rear cleaning edge and acting to open the nap to be cleaned, due to its digging-in effect, toward the front or rear suction channel, depending on the direction of movement.

Injector for turbine engines

Abstract: An injector for turbine engines which includes a shaped injector core fitted with an eccentric spinner inlet communicating with a cylindrical, annular fuel spinner chamber and a preheater or evaporator for preheating and vaporizing fuel, wherein the vaporized fuel is eccentrically injected into the fuel spinner chamber to effect a spinning fuel sequence around a fuel guidance pin extending through the center of the fuel spinner chamber. Compressed air from the turbine compressors flows through the primary nozzle of an air guidance nozzle surrounding the injector core into a shaped secondary nozzle, where the air mixes with the spinning fuel at a selected air flow angle to facilitate thorough mixing of the fuel and air as the combustible mixture is channeled into the annular turbine combustor. The unique spinning component applied to the preheated, vaporized fuel and manner of introducing the compressed air into the spinning fuel using multiple, spaced injectors and corresponding air guidance nozzles effects exceptionally good air-fuel mixing and facilitates increased turbine operating efficiency and reduction of NOX emissions in the turbine exhaust gases.

Dispenser for a product with a liquid-to-pasty consistency

Abstract: The invention relates to an applicator nozzle (2) for the dispensing and the application of a product (P) with a liquid-to-pasty consistency, comprising an application surface (5) provided with at least one dispensing orifice (61). This nozzle is provided with a one-way valve (62b) allowing the product to be dispensed and preventing the ambient air from coming into contact with the product. The invention also relates to a dispensing unit comprising such an applicator nozzle (2), a reservoir for the product (P), and system (M) capable of producing the ejection of the product (P) through the dispensing orifice (61) of the applicator nozzle (2).