Showing papers on "Nozzle published in 1982"

Mechanism of atomization of a liquid jet

Abstract: In the atomization regime of a round liquid jet, a diverging spray is observed immediately at the nozzle exit. The mechanism that controls atomization has not yet been determined even though several have been proposed. Experiments are reported with constant liquid pressures from 500 psia (33 atm) to 2500 psia (166 atm) with five different mixtures of water and glycerol into nitrogen, helium, and xenon with gas pressures up to 600 psia (40 atm) at room temperature. Fourteen nozzles were used with length‐to‐diameter ratios ranging from 85 to 0.5 with sharp and rounded inlets, each with an exit diameter of about 340 μm. An evaluation of proposed jet atomization theories shows that aerodynamic effects, liquid turbulence, jet velocity profile rearrangement effects, and liquid supply pressure oscillations each cannot alone explain the experimental results. However, a mechanism that combines liquid–gas aerodynamic interaction with nozzle geometry effects would be compatible with our measurements but the specific process by which the nozzle geometry influences atomization remains to be identified.

Production of separation-nozzle systems for uranium enrichment by a combination of X-ray lithography and galvanoplastics

Abstract: X-ray lithography using synchrotron radiation has been applied in a multi-step process for the production of plastic moulds to be used in the fabrication of separation nozzles by electrodeposition. For characteristic dimensions of a few microns a total height of the nozzle structure of about 400 μm has been achieved. Structural details of about 0.1 μm are being reproduced across the total thickness of the polymer layer. The surface finish of metallic separation nozzles produced by electrodeposition was equivalent to the high quality of the polymer surface. The separation-nozzle systems fabricated by the described method allow an increase by a factor three of the gas pressure in separationnozzle plants as compared to the present standard. This results in considerable savings in the enrichment of 235U for nuclear power production.

Broadband Shock Noise from Supersonic Jets

Abstract: Broadband shock noise from supersonic jets is investigated through acoustic measurements in both the near and far fields. The peak Helmholtz number of broadband shock noise from unheated convergent nozzles is found to be independent of nozzle pressure ratio when based on the length of the shock cells and the ambient speed of sound. Excellent agreement between power spectral densities measured at various far-field angles is obtained at and above the peak shock noise frequency when source convection and directivity effects are included. The directivity of broadband shock noise is found to be pointed in the upstream direction, with omnidirectionality being approached only at high pressure ratios. For both convergent and convergent-divergent nozzles, the relative importance of shock noise with respect to jet-mixing noise is found to be maximum near the pressure ratio at which a Mach disk begins to form in the jet. Near-field measurements point to a limited portion of the shock cell system as the region of dominant broadband noise emission from a highly underexpanded convergent nozzle.

Piezoelectric oscillated nozzle

Abstract: An arrangement for discharging liquid droplets comprises a housing including a chamber for holding liquid therein having an intake port connected to a liquid supply container, a vibrating member secured to the housing in pressure transmitting relation with the liquid in the chamber. The vibrating member is formed with at least one nozzle opening therein through which the liquid is discharged forwardly of the housing. A piezoelectric transducer is secured to the vibrating member for inducing a rearward displacement therein to discharge a small quantity of liquid through the nozzle opening.

Hydrodynamics of gas stirred melts: Part I. Gas/liquid coupling

Abstract: A hydrodynamic model of submerged gas injection systems and their effects on liquid metal stirring is presented. It is argued that hydrodynamic conditions at the nozzle, tuyere, or plug are not critical to flow recirculation produced in large cylindrical vessels(i.e., furnaces or ladles). An analysis of a buoyancy driven plume generated through gas injection shows that gas voidages are usually quite low (less than 10 pct). By equating the energy supplied by rising bubbles to turbulent energy losses within the bath, it is shown that mean plume velocities can be predicted using the relationship,U p α (Q 1/3 L 1/3)/R1/3 whereU p equals mean plume velocity,Q is gas flow rate (at mean height and temperature),L is depth of liquid, andR is radius of the vessel. Associated rates of liquid turnover as a function of vessel dimensions and gas flow rate can also be predicted and these are similarly presented.

Control method and apparatus for liquid distributor

Abstract: A liquid sprayer has a tank for storing liquid, a boom supporting spraying nozzles, and a pump and liquid control system for supplying liquid under pressure to the spraying nozzle in a manner that maintains substantially uniform liquid dispensing density independent of variations in the ground speed of the sprayer. A ground speed sensor, a liquid pressure sensor, and a liquid flow meter sends signals to a controller to regulate a valve that controls the rate of flow of liquid to the spraying nozzles.

Submerged laminar jet impingement on a plane

Abstract: Submerged laminar jet impingement on a plane is studied using computation. Steady-state Navier-Stokes equations for the axisymmetric case are solved numerically. The extent of the infinite flow is approximated by applying the boundary conditions at a finite but sufficiently large distance. The tube-exit velocity profile is assumed to be either a fully developed parabolic profile or a flat profile. For the former case, two different nozzle heights from the target plane are considered. The presence of a toroid-shaped eddy at low values of Reynolds number, Re, leads to some interesting observations such as the manner in which the wall shear stress depends on Re. An increase in the height of the nozzle exit from the target plane decreases the wall shear stress, more so at lower values of Re. A change from the parabolic exit velocity profile to the flat profile leads to a decrease in wall shear stress due to decreased momentum flux. The study was motivated by experiments designed to measure the yield shear strength of the vascular endothelium wherein a small saline jet was used to erode the tissue by normal impingement.

Nonlinear stability and instability of transonic flows through a nozzle

Abstract: We study transonic flows along a nozzle based on a one-dimensional model. It is shown that flows along the expanding portion of the nozzle are stable. On the other hand, flows with standing shock waves along a contracting duct are dynamically unstable. This was conjectured by the author based on the study of noninteracting wave patterns. The author had shown earlier that supersonic and subsonic flows along a duct with various cross sections are stable. Basic to our analysis are estimates showing that shock waves tend to decelerate along an expanding duct and accelerate along a contracting duct.

High velocity particulate containing fluid jet apparatus and process

Abstract: Apparatus and process for introducing solid particles into fluid streams under accurate control. Several embodiments of nozzle apparatus are disclosed utilizing a central fluid orifice or orifices and peripheral solids orifices for mixing the solids into the fluid stream. When multiple fluid orifices are utilized, an area of lower pressure is formed in the central portion of the combined fluid stream thereby aiding in the mixture of the solids into the fluid stream. A flow shaping nozzle is provided at the exit of the apparatus to increase the mixing of the solids within the fluid jets stream. The flow shaping nozzle may have both axial and radial freedom of movement for forming the fluid-solids stream and self-alignment, respectively. The apparatus and process of this invention, in one preferred embodiment, involves introduction of the solids in the form of a foam into the fluid jet stream. The apparatus and process of this invention is particularly well suited for abrasive uses of cutting hard materials such as reinforced concrete and steel, as well as utilization with a peripheral air shroud for underwater purposes.

Method for producing plastic microfilaments

Abstract: Relatively long plastic microfilaments are used to make reinforcing, filler materials and fabrics. A blowing gas is applied at a positive pressure to the inert surface of a liquid plastic film formed across a coaxial blowing nozzle to blow the film and form an elongated hollow tube having a thinned wall or weakened portion. An entraining fluid is directed at an angle over and around the blowing nozzle and as it passes over and around the blowing nozzle, it dynamically induces a pulsating or fluctuating pressure field at the opposite side of the blowing nozzle in the wake thereof and produces a laminar flow of entraining fluid in the vicinity of the forming elongated tube. The continued movement of the entraining fluid over the elongated tube produces asymmetric fluid drag forces on the tube, and at the thinned wall or weakened wall portion longitudinally breaks the tube to form a multiplicity of plastic microfilaments, and detaches the plastic microfilaments from the elongated tube and from the coaxial blowing nozzle and the detached microfilaments are carried away from the blowing nozzle. Quench nozzles or heating nozzles may be disposed below and on either side of the blowing nozzle to direct cooling or heating fluid at and into contact with the plastic microfilaments to cool or heat and cure, solidify and harden the plastic to form hard, smooth plastic microfilaments.

Solar collector comprising transparent hollow plastic microspheres as insulation material

Abstract: The hollow plastic microspheres 17 are made by forming a liquid film of thermoplastic or thermosetting plastic composition across a coaxial blowing nozzle 5, applying a blowing gas 10 at a positive pressure to the inner surface of the plastic film to blow the film and form an elongated cylinder shaped liquid film 12 of plastic. A transverse jet 13 is used to direct an entraining fluid 14 over and around the blowing nozzle 5, at an angle to the axis of the blowing nozzle. The entraining fluid 14 as it passes over and around the blowing nozzle 5 fluid dynamically induces a pulsating or fluctuating pressure field at the opposite or lee side of the blowing nozzle in the wake or shadow of the coaxial blowing nozzle. The continued movement of the entraining fluid 14 over the elongated cylinder 12 produces asymmetric fluid drag forces on the cylinder and closes and detaches the elongated cylinder from the coaxial blowing nozzle and the detached cylinder by the action of surface tension forms into a spherical shape 17. The hollow plastic microspheres can be made from low heat conductivity plastic compositions and blown with a low heat conductivity gas and used to make improved insulation materials and composites and insulating systems. The hollow plastic microspheres 17 can be made to contain a thin transparent or reflective metal coating 20 deposited on the inner wall surface of the microspheres.

Method and apparatus for producing microfilaments

Abstract: Relatively long microfilaments made from a low heat conductivity glass composition The microfilaments are used to make insulation and/or filler materials The microfilaments are made by forming a liquid film of molten glass across a coaxial blowing nozzle (5), applying a blowing gas (10) at a positive pressure on the inner surface of the glass film to blow the film and form an elongated hollow tube or cylinder (12) of molten glass Means are provided for forming a thinned wall or weakened portion of the forming elongated tube or cylinder A transverse jet (13) is used to direct an entraining fluid (14) over and around the blowing nozzle (5) at an angle to the axis of the blowing nozzle The entraining fluid (14) as it passes over and around the blowing nozzle (5) fluid dynamically induces a pulsating or fluctuating pressure field at the opposite or lee side of the blowing nozzle in the wake or shadow of the coaxial blowing nozzle and produces a laminar flow of entraining fluid in the vicinity of the forming elongated tube or cylinder The continued movement of the entraining fluid (14) over the elongated cylinder (12) produces asymmetric fluid drag forces on the cylinder, and at the thinned walled or weakened portion longitudinally breaks the cylinder to form a multiplicity of microfilaments, and detaches the microfilaments from the elongated cylinder and from the coaxial blowing nozzle and the detached filaments are carried away from the blowing nozzle

Fuel injection system for internal combustion engines

Abstract: A fuel injection system for an internal combustion engine employing a rotary valve for delivering fuel to fuel injectors in which fuel injection timing is precisely controlled to an optimum range by automatically controlling the rotary valve in response to the number of revolutions of the engine. The system includes a high pressure accumulator connected to a fuel pump and a low pressure accumulator connected to a tank through a variable restrictor valve. The rotary valve functions to selectively connect each injector to the high and low pressure accumulators as it rotates whereby metered amount of fuel can be fed into a plunger chamber of each injector when a piston chamber of the injector is connected to the low pressure accumulator and the fuel can be injected through nozzle orifices when the piston chamber is connected to the high pressure accumulator.

Low-frequency sound radiation and generation due to the interaction of unsteady flow with a jet pipe

Abstract: In this paper we examine the low-frequency sound radiated when various types of unsteady flow interact with a jet pipe. In each case we solve the problem exactly by the Wiener-Hopf technique, producing results valid for arbitrary internal and ex- ternal Mach numbers and temperatures, discuss the importance of a Kutta condition at the duct exit, and provide an interpretation, in elementary terms, of the radiated sound field using the Lighthill acoustic analogy. A central feature is that the solutions are always obtained subject to a causality requirement, regardless of whether or not a Kutta condition is imposed at the pipe lip. When low-frequency sound propagates down the jet pipe, little of it reaches the far field, and the major disturbance outside the pipe is that associated with the jet instability waves. At subsonic jet speeds and low-enough Strouhal number these waves transport kinetic energy at a rate precisely balancing the loss of acoustic energy from the pipe, resulting in a net attenuation of the sound power. For supersonic jet condi- tions a further wave motion, the unsteady-flow counterpart of the steady wave struc- ture of an imperfectly expanded jet, is present in addition to the instability wave. We use the Lighthill acoustic analogy to show that, for high-enough jet Mach number and temperature, the sound radiation is caused largely by quadrupole sources arising from the jet instability waves. An alternative interpretation uses the acoustic analogy incorporating a mean flow due to Dowling, Ffowcs Williams and Goldstein, and expresses the far-field sound as the sum of contributions from monopoles and dipoles distributed over the duct exit. The directivity and power of the calculated far-field sound are in good agreement with experiments. We also calculate the sound scattered by the jet pipe when there is an incident external sound field, and show a previously published result to be in error. In general, the flbw phenomena produced by internal and external incident sound fields are similar. Finally, we discuss the effects of nozzle contraction. We find that the radiated sound field is little changed in character, but that the reflection properties of the nozzle may be drastically altered.

Capping device for ink jet nozzle

Abstract: A capping device for capping the front end of an ink jet nozzle, wherein an ink absorbing element is provided in the nozzle capping unit in such a position as to be brought into contact with the front end of the ink jet nozzle.

Aerodynamic levitation of laser-heated solids in gas jets

Abstract: The aerodynamic levitation technique is developed for studies of high-temperature material properties and gas/condensed-phase reaction kinetics. Stable levitation is demonstrated in a supersonic jet from a 0.081 cm nozzle with 0.03-0.20 g 0.24-0.47 cm diameter solid spheres at a height between 0.7-2.0 cm above the nozzle and ambient pressures between 1.1-18 Torr. A model of supersonic jet levitation is developed which accurately predicts the values of height vs pressure over the full range of conditions investigated. It is found that the efficiency with which jet momentum is converted into levitation force decreases with the jet/specimen diameter ratio and the jet Reynolds number, and the rate of jet spreading with distance from the nozzle is found to agree with that measured by pitot tube traverses of the jet. In addition, laser heating is shown to reduce the jet momentum required for levitation at a given height and to increase levitation stability. Measurements of sphere levitation in subsonic gas jets show that the required jet momentum flow rate exceeds the specimen weight by about 2/the specimen drag coefficient at its terminal free-fall speed under ambient conditions.

Method for etching and controlled chemical vapor deposition

Abstract: A high velocity stream of gas comprising of either the carrier gas or one or more film forming or removing components is shot through a shooting means such as a nozzle or orifice in the form of a high speed stream of gas in a chemical vapor deposition growth chamber or within an attachment receiving reaction gases from such a chamber. This gas or mixture of gases entrains all of the adjacent gases within the vicinity of the shooting nozzle or orifice and is subsequently swept through a diffusion tube. The diffusion tube compresses and exhausts the gas mixture at a pressure sufficient to drive the combined gas mixture through a heat exchanger and finally back into the growth chamber. The gases within the growth chamber are provided for entrainment downstream to a heated base or substrate which is being coated with a thin film or epitaxial layer of film forming components contained in a carrier gas. The entrained temperature adjusted gas mixture together with the high velocity gas mixture is reintroduced upstream of the same heated base or substrates in the growth chamber.

Three-Dimensional Model of Spray Combustion in Gas Turbine Combustors

Abstract: A mathematical model of the three-dimensional two-phase reacting flows in gas turbine combustors has been developed which takes into account the mass, momentum, and energy coupling between the phases. The fundamental equations of motion of the droplets are solved numerically in a Lagrangian frame of reference, using a finite-difference solution of the governing equations of the gas. Well-known relations are used to model the heat and mass transfer processes and the initial droplet heat-up is allowed for. The entire fuel spray is constructed using a finite number of size ranges obeying a two parameter droplet size distribution. The results are found to be in close agreement with experimental data. An important feature of this analytical technique is that it permits the rational selection or specification of fuel nozzle design.

Rotating laser beam with coincident gas jet

Abstract: An apparatus provides to a surface a laser beam and gas stream that impinge and rotate in coincidence. The apparatus comprises an optical system (11) to direct the laser beam to a spot in a plane and a stationary gas plenum (16) through which gas passes en route to an outlet nozzle (18) that directs the gas stream to the same spot. The optical system and nozzle rotate in synchronism to cause the spot to trace a circle. The apparatus finds application in materials processing, such as welding and cutting (trepanning).

Electrostatic powder spray gun nozzle

Abstract: The invention is concerned with a nozzle assembly for a powder spray gun which may be an electrostatic gun and which includes an electrically non-conductive barrel through which a high voltage electrical path passes. The nozzle assembly is mounted in the open forward end of the barrel and includes a sleeve (46) located on the centre axis of the barrel for directing a flow of a pressurised gas, e.g. air, through the centre of the nozzle assembly, a nozzle (58) surrounding the sleeve defining an annular flow path for powder spray coating material encircling the flow of pressurised air and an air deflector cap (64) for directing the pressurised air radially outwardly and into the flow of powder spray coating material being emitted from the nozzle. The air impacts the powder coating material to form a conical spray pattern of coating material. The gun may also include an electrode (37) extending out of the nozzle assembly for electrostatically charging the powder. The nozzle assembly eliminates mechanical powder deflectors and the problems attenaant therewith.

Laser cutting nozzle

Abstract: A laser cutting nozzle for use with a laser cutting apparatus directing a focused beam to a spot on a work piece. The nozzle has a cylindrical body with a conical tip which together have a conically shaped hollow interior with the apex at a small aperture through the tip. The conical hollow interior is shaped to match the profile of the laser beam, at full beamwidth, which passes through the nozzle to the work piece. A plurality of gas inlet holes extend through the body to the hollow interior and are oriented to produce a swirling flow of gas coaxially through the nozzle and out the aperture, aligned with the laser beam, to the work piece. BACKGROUND OF THE INVENTION

Fluid dynamics of vertical submerged gas jets in liquid metal processing systems

Abstract: High speed cinematography and a pressure trace technique have been used to investigate the fluid dynamics of inert gas jets injected vertically upward into water, molten tin, lead-tin alloy, and iron. Two flow regimes of jet behavior were observed: one in which unstable bubbles were produced at the jet nozzle, and one in which a steady cone of gas emerged from the nozzle and broke up continuously into small bubbles. The transition between bubbling and continuous jet flow was controlled by the mass flow of gas per unit area of the jet and occurred at a flow rate of approximately 40 g/cm2 s in all of the systems studied.

Nozzle tip for pulverized coal burner.

Abstract: An improved nozzle tip (10) for a burner on a pulverized coal-fired furnace for receiving a stream of pulverized coal and air discharging from the coal delivery pipe (50) of the burner and directing the pulverized fuel and air stream into the furnace, is comprised of a base body (20), a replaceable highly abrasion resistant insert (30), and a replaceable highly temperature resistant end cap (40) which is readily attachable by mechanical means (28, 48) to the base body with the abrasion resistant insert disposed therein. The insert defines a highly abrasion resistant flow conduit through the nozzle tip from the discharge end of the base body to the receiving end of the end cap through which the pulverized fuel and air stream passes from the burner into the furnace.

Ejector and method of controlling same

Abstract: An adjustable ejector capable of adjusting the fluid flow conditions resulting from fluid flow through the ejector. Adjustment means are provided for varying the fluid presentation size ratio of the inlet nozzle throat to the mixing throat. The adjustment means includes at least one adjustable path structure disposed in either the inlet nozzle or the mixing throat, or both.

Quick disconnect nozzle

Abstract: The invention comprises a quick disconnect nozzle including a nozzle body and a nozzle tip, wherein the nozzle body may be connected to a source of fluid and the nozzle tip is separable from the body by a single twist type action, yet the nozzle may be securely locked in the body by an interlocking engagement between the nozzle and body that is engaged and disengaged by relative twisting of the two parts. The locking action is obtained by the engagement of cooperative elements on the two parts including oppositely disposed undercut shoulders on the nozzle body and a pair of rounded projections on the nozzle tip which are engaged under the opposing shoulders by the relative twisting action. The interlocked relationship is maintained by a combination sealing member and pressure device that effectively seals the connection between the nozzle body and tip and exerts pressure therebetween to secure the locked connection.

Adhesive dispensing system

Abstract: An adhesive applicator has a nozzle through which adhesive can be dispensed to sheets of a set as the sheets are driven seriatim past the nozzle. Adhesive is furnished in a cartridge which is pressurized so that the adhesive is delivered from the cartridge to the nozzle under pressure. A valve controls the flow of adhesive from the nozzle, and the valve is under control of a logic and control unit. The logic and control unit receives signals from various sensors or detectors indicating, inter alia, the presence of an adhesive cartridge, the level of adhesive in the cartridge, the flow of adhesive from the nozzle, and the amount of adhesive in a collection bottle which receives surplus adhesive dispensed from the nozzle but not applied onto a sheet. The logic and control unit is capable of operating the valve that controls flow of adhesive from the nozzle so that adhesive is selectively dispensed from the nozzle to all but one sheet of a set of sheets. A purge cycle is initiated if adhesive does not flow from the nozzle when commanded to flow by the logic and control unit.

Jet mixing of fluids in tanks

Abstract: An experimental investigation was made of the mixing of liquids in a tank where the liquid jet was injected through a nozzle The mixing time was defined as the time required to reduce the concentration variation within 1% of the mixed mean value and was measured by an impulse response The circulation time was also obtained from the response curve It was found that in the circulation flow regime of mixing (Re>3 ×104) there exists an optimum nozzle depth for rapid mixing It ranges from the liquid surface level to three-quarters of the liquid depth when the liquid depth is equal to the tank diameter, and is the mid-depth of the liquid when the liquid depth is smaller than the tank diameter When the nozzle height is within one-fourth of the tank diameter, it is efficient for rapid mixing to tilt the nozzle upwards enough to prevent the formation of a wall jet, which induces circulations of small variance of circulation time