Showing papers on "Nozzle published in 2004"

Simultaneous measurements of scalar and velocity field evolution in turbulent crossflowing jets

Abstract: Simultaneous planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) yield measurements of two-dimensional jet fluid concentration and velocity fields in turbulent crossflowing jets. The jet-to-crossflow velocity ratio is r = 5.7 and the jet exit Reynolds number is approximately 5000. The measurements are focused on the developing region of the flow. Two flow configurations are studied, one in which the jet nozzle is flush with the tunnel wall and the other where the nozzle protrudes into the uniform region of the tunnel flow. The jet nozzle in both cases is a simple pipe. The averaged scalar and velocity fields show a strong similarity in growth rates and centreline decay rates between the two nozzle configurations when using the centreline downstream coordinate s

Numerical Characterization of Particle Beam Collimation: Part II Integrated Aerodynamic-Lens-Nozzle System

Abstract: As a sequel to our previous effort on the modeling of particle motion through a single lens or nozzle, flows of gas–particle suspensions through an integrated aerodynamic-lens–nozzle inlet have been investigated numerically. It is found that the inlet transmission efficiency (ηt) is unity for particles of intermediate diameters (Dp ∼ 30–500 nm). The transmission efficiency gradually diminishes to ∼40% for large particles (Dp > 2500 nm) because of impact losses on the surface of the first lens. There is a catastrophic reduction of ηt to almost zero for very small particles (Dp ≤ 15 nm) because these particles faithfully follow the final gas expansion. We found that, for very small particles, particle transmission is mainly controlled by nozzle geometry and operating conditions. A lower upstream pressure or a small inlet can be used to improve transmission of very small particles, but at the expense of sampling rate, or vice versa. Brownian motion exacerbates the catastrophic reduction in ηt for small parti...

Gas turbine engine exhaust nozzle

Abstract: A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle and a plurality of tabs which extend in a generally axial direction from a downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, where the tabs interact with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, where the tabs are substantially aerodynamically unobtrusive.

Liquid jet and recovery system for immersion lithography

Abstract: A liquid jet and recovery system for an immersion lithography apparatus has arrays of nozzles arranged to have their openings located proximal to an exposure region through which an image pattern is projected onto a workpiece such as a wafer. These nozzles are each adapted to serve selectively either as a source nozzle for supplying a fluid into the exposure region or as a recovery nozzle for recovering the fluid from the exposure region. A fluid controlling device functions to cause nozzles on selected one or more sides of the exposure region to serve as source nozzles and to cause nozzles on selected one or more of the remaining sides to serve as recovery nozzles such that a desired flow pattern can be established for the convenience of immersion lithography.

The effects of nozzle diameter on impinging jet heat transfer and fluid flow

Abstract: The effects of nozzle diameter on heat transfer and fluid flow are investigated for a round turbulent jet impinging on a flat plate surface. The flow at the nozzle exit has a fully developed velocity profile. A uniform heat flux boundary is created at the plate surface by using gold film Intrex, and liquid crystals are used to measure the plate surface temperature. The experiments are performed for the jet Reynolds number (Re) of 23,000, with a dimensionless distance between the nozzle and plate surface (L/d) ranging from 2 to 14 and a nozzle diameter (d) ranging from 1.36 to 3.40 cm

Atomization process for metal powder

Abstract: A new atomization process has been developed, which combines pressure and gas atomization. The melt leaves the pressure nozzle as a hollow thin film cone. After the pre-filming step, the melt is atomized by a gas stream delivered by a ring nozzle. The objectives of this investigation are to achieve a narrow size distribution and low specific gas consumption compared to conventional gas atomization techniques. Both lead to a higher efficiency and low costs. Tin and some alloys have been atomized successfully with this technique. The mass median diameters from different experiments are between 20 and 100 μm. Sieving analysis of the tin powder shows close particle size distributions.

Modelling powder concentration distribution from a coaxial deposition nozzle for laser-based rapid tooling

Abstract: Direct laser deposition is a solid freeform fabrication process that is capable of producing fully dense components with full structural integrity and is greatly enhanced by. the use of an onmidirectional coaxial powder nozzle to supply the build material. In order to optimize the technique, accurate control of the two critical operational parameters of material feed rate and incident laser power intensity is necessary. Both parameters are affected by the axial powder stream concentration between the nozzle and the deposition point. In this work, a mathematical model for the powder concentration distribution is developed and the results from it compared with an experimental investigation using optical and image analysis techniques. The two show good agreement. The application of the model to the evaluation of nozzle geometry and the calculation of laser beam attenuation are demonstrated.

Theoretical components of the VASIMR plasma propulsion concept

Abstract: The ongoing development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) involves basic physics analysis of its three major components: helicon plasma source, ion cyclotron-resonance heating module, and magnetic nozzle. This paper presents an overview of recent theoretical efforts associated with the project. It includes (1) a first-principle model for helicon plasma source, (2) a nonlinear theory for the deposition of rf-power at the ion cyclotron frequency into plasma flow, and (3) a discussion of the plasma detachment mechanism relevant to VASIMR.

Electrostatic spraying device

Abstract: An electrostatic spraying device has a removable cartridge with a reservoir containing a volume of liquid compositions to be electrically sprayed. The device includes a nozzle for dispensing the liquid and an emitter electrode disposed adjacent to the nozzle for charging the liquid composition just being dispensed from the nozzle. A field electrode surrounds the reservoir in order to charge the liquid composition within the reservoir, thereby avoiding an occurrence of electric current which would deteriorate the composition remaining in the reservoir. The reservoir is at least partially made of deformable material such that the reservoir is capable of receiving pressure to deform and thus supply the liquid composition out of the reservoir. Thus, the reservoir can be designed into a simple and compact structure, thereby providing an increased liquid containing volume in relation to the bulk of the removable cartridge.

Plasma processing apparatus

Abstract: PROBLEM TO BE SOLVED: To improve process efficiency by allowing change of a processing condition on the way, without replacing a flow regulating plate, if conditions of plasma processing such as etching process are changed. SOLUTION: The plasma gas is guided to an object to be processed by way of a flow-regulating plate (40), having many nozzle holes (42) for plasma process within a vacuum chamber (10). A flow control means controls, from the outside of the vacuum vessel (10), the flow of plasma gas generated by the flow-regulating plate (40), by using an interference plate (60) that can approach/recede from the flow-regulating plate (40) in the vacuum vessel (10). The interference plate (60) is formed of, for example, a disc parallel to the flow regulating plate (40). By changing the interval between the disc and the interference plate, the flow of the plasma gas, passing through the nozzle hole (42), is controlled. The plasma processing apparatus can be applied to dry etching apparatus. COPYRIGHT: (C)2004,JPO

Analysis of the Influence of Diesel Nozzle Geometry in the Injection Rate Characteristic

Abstract: An experimental research study was carried out to analyze the influence of different orifice geometries (conical and cylindrical) on the injection rate behavior of a Common-Rail fuel injection system. For that purpose, injection tests in two different injection test rigs were conducted. This behavior of the injection rate in the different nozzles was characterized by using the non-dimensional parameters of cavitation number (K), discharge coefficient (Cd) and Reynolds number (Re). First, some relevant physical properties of the injected fuel were accurately characterized (density, kinematic viscosity and sound speed in the fluid) in a specific test rig as a function of the operating conditions (pressure and temperature). The behavior of both nozzles was analyzed at maximum injector needle lift under steady flow conditions in a cavitation test rig. Injection pressure and pressure at the nozzle discharge were controlled in order to modify the flow conditions. In addition, the nozzles were characterized in real unsteady flow conditions in an injection-rate test rig. From the raw results, the values of the relevant parameters were computed, and the occurrence of cavitation was clearly identified

Study of transient flow and particle transport in continuous steel caster molds: Part I. Fluid flow

Abstract: Unsteady three-dimensional flow in the mold region of the liquid pool during continuous casting of steel slabs has been computed using realistic geometries starting from the submerged inlet nozzle. Three large-eddy simulations (LES) have been validated with measurements and used to compare results between full-pool and symmetric half-pool domains and between a full-scale water model and actual behavior in a thin-slab steel caster. First, time-dependent turbulent flow in the submerged nozzle is computed. The time-dependent velocities exiting the nozzle ports are then used as inlet conditions for the flow in the liquid pool. Complex time-varying flow structures are observed in the simulation results, in spite of the nominally steady casting conditions. Flow in the mold region is seen to switch between a “double-roll” recirculation zone and a complex flow pattern with multiple vortices. The computed time-averaged flow pattern agrees well with measurements obtained by hot-wire anemometry and dye injection in full-scale water models. Full-pool simulations show asymmetries between the left and right sides of the flow, especially in the lower recirculation zone. These asymmetries, caused by interactions between two halves of the liquid pool, are not present in the half-pool simulation. This work also quantifies differences between flow in the water model and the corresponding steel caster. The top-surface liquid profile and fluctuations are predicted in both systems and agree favorably with measurements. The flow field in the water model is predicted to differ from that in the steel caster in having higher upward velocities in the lower-mold region and a more uniform top-surface liquid profile. A spectral analysis of the computed velocities shows characteristics similar to previous measurements. The flow results presented here are later used (in Part II of this article) to investigate the transport of inclusion particles.

Substrate processing apparatus

Abstract: PROBLEM TO BE SOLVED: To provide a substrate processing apparatus, which can secure a spraying uniformity in a sheet width direction without increasing the number of nozzles for upsizing the substrate. SOLUTION: A processing liquid is supplied to the surface of a transported substrate from a plurality of spray nozzles 32 provided above a substrate transporting line and arranged in a substrate transporting direction and in a sheet width direction perpendicular thereto. As many spray nozzles 32, a pyramid nozzle spraying the processing liquid in a pyramid-shape is used. Among a plurality of nozzle rows in parallel to the sheet width direction, in the odd numbered nozzle rows, the side end portions of the spray zone between nozzles adjacent to the sheet width direction are overlapped to each other, and in the even numbered nozzle rows, the side end portions of the spray zone between nozzles adjacent to the sheet width direction are overlapped to each other to form, as a whole, the region where the spray zones are overlapped triply, intermittently in the sheet width direction. In each nozzle row, the odd numbered nozzle rows are shifted by about 1/2 pitches from the even numbered nozzle rows for the nozzle position in the substrate transporting direction not to overlap the spray zones between nozzles adjacent to the substrate transporting direction. Each spray nozzle 32 is fluctuated in the sheet width direction. COPYRIGHT: (C)2005,JPO&NCIPI

Exhaust emission control device

Abstract: PROBLEM TO BE SOLVED: To provide an exhaust emission control device for removing urea precipitated in an exhaust pipe. SOLUTION: The exhaust emission control device uses a NOx reduction catalyst 14 located on the downstream side with urea water solution as reducing agent injected and supplied from an injection nozzle 22 into the exhaust pipe 16 for reducing and purifying NOx in exhaust gas into harmless components. An electric heater 28 and a heat insulating material 30 are arranged around the exhaust pipe 16 including portions in which the urea water solution injected and supplied from the injection nozzle 22 is deposited. In accordance with a signal from a temperature sensor 36 for detecting an exhaust pipe temperature Te of the exhaust pipe 16 in which the electric heater 28 is arranged, the operation of the electric heater 28 is controlled by a control unit 44 so that the exhaust pipe temperature Te is a melting point of urea or higher. Thus, the urea is melted and removed even when precipitated by the evaporation of of water from the urea water solution deposited on the inner wall of the exhaust pipe 16. COPYRIGHT: (C)2005,JPO&NCIPI

Side-Load Phenomena in Highly Overexpanded Rocket Nozzles

Abstract: The operation of rocket engines in the overexpanded mode, that is, with the ambient pressure considerably higher than the nozzle exit wall pressure, can result in dangerous lateral loads acting on the nozzle. These loads occur as the boundary layer separates from the nozzle wall and the pressure distribution deviates from its usual axisymmetric shape. Different aerodynamic or even coupled aerodynamic/structural mechanic reasons can cause an asymmetric pressure distribution. A number of subscale tests have been performed, and three potential origins of side loads were observed and investigated, namely, the pressure fluctuations in the separation and recirculation zone due to the unsteadiness of the separation location, the transition of separation pattern between free-shock separation and restricted-shock separation, and aeroelastic coupling, which indeed cannot cause but do amply existing side loads to significant levels. All three mechanisms are described in detail, and methods are presented to calculate their magnitude and pressure ratio at which they occur.

Suction wet jet mop

Abstract: A cleaning device (10, 300, 400, 480, 490, 500) includes a housing (28, 313, 422, 482, 502), part of which may be a handle (14, 314, 516). A cleaning head (12, 12', 312, 412, 520) is pivotally mounted to the housing or to the handle. The cleaning head selectively holds a cleaning pad (70, 70', 370, 526) for collecting liquids, dust and debris from a surface to be cleaned. A suction nozzle (18, 318, 438, 508) is carried by the cleaning head or the handle. A dirt collecting receptacle (208) is mounted to the housing and is in fluid communication with the suction nozzle and with a suction fan and motor assembly (30). At least one spray nozzle (22, 22', 330, 332, 432, 506) can be mounted on the suction nozzle, the cleaning head, the housing or the handle. A liquid delivery system (90, 90') delivers a cleaning fluid to the at least one spray nozzle.

Selective control of flow coherence in triangular jets

Abstract: The triangular jet was investigated for use as a passive device to enhance fine-scale mixing and to reduce the coherence of large-scale structures in the flow. The suppression of the structures is vital to the enhancement of molecular mixing, which is important for efficient chemical reactions including combustion. The sharp corners in the jet injector introduced high instability modes into the flow via the non-symmetric mean velocity and pressure distribution around the nozzle. Both aerodynamic and hydrodynamic flows showed the difference between the flow at the corner (vertex) and at the flat side. While highly coherent structures could be generated at the flat side, the corner flow was dominated by highly turbulent small-scale eddies. The flow characteristics were tested using hotwire anemometry for mean flow and turbulence analysis, and flow visualization in air and water.

New Method for Jet Noise Reduction in Turbofan Engines

Abstract: A new method for reducing large-scale mixing noise from dual-stream jets is presented. The principle is reduction of the convective Mach number of turbulent eddies that produce intense downward sound radiation. In a jet representing the coaxial exhaust of a turbofan engine, this is achieved by tilting downward, by a few degrees, the bypass (secondary) plume relative to the core (primary) plume. The misalignment of the two flows creates a thick low-speed secondary core on the underside of the high-speed primary flow. The secondary core reduces the convective Mach number of primary eddies, thus hindering their ability to generate sound that travels to the downward acoustic far field. Tilting of the bypass stream is possible by means of fixed or variable vanes installed near the exit of the bypass duct. Subscale aeroacoustic experiments simulated the exhaust flow of a turbofan engine with bypass ratio 6.0. Deflection of the bypass stream resulted in suppression of the peak overall sound pressure level by 4.5 dB and the effective perceived noise level by 2.8 dB. For the nozzle configuration used, the thrust loss is estimated at around 0.5% with the vanes activated and 0.15% with the vanes deactivated.

A bottom-up electrospinning devices, and nanofibers prepared by using the same

Abstract: A conventional electrospinning devices is problematic in that it is unable to mass-produce a nanofiber web and the quality of a produced nanofiber web is poor. To solve the above problem, the present invention provides a bottom-up electrospinning devices, wherein [I] the outlets of nozzles 5 installed on a nozzle block 4 are formed in an upper direction; [II] a collector 7 is located on the top part of the nozzle block 4; and [III] overflow removing nozzles 4a and air feeding nozzles 4b are sequentially installed around nozzle outlets.

Study of Transient Flow and Particle Transport in Continuous Steel Caster Molds: Part II. Particle Transport

Abstract: Particle motion and capture in continuous steel casters were simulated using a Lagrangian trajectory-tracking approach, based on time-dependent flow fields obtained from large-eddy simulations (Part I of this article). A computation was first conducted on a water model of a full-scale standard slab caster, where measurements were available. It simulated the transport of 15,000 plastic particles and their removal by a screen positioned near the mold top surface. The computation shows the screenremoval fractions to be 27±5 pct for 0 to 10 seconds and 26±2 pct for 10 to 100 seconds, which agrees with previous measurements. The flow exiting the nozzle was relatively uniform, and turbulent motion in the domain was very chaotic, so particle removal did not depend on the initial location of particles introduced in the nozzle port. A computation of motion and capture of 40,000 small inclusions (10 and 40 µm) was then performed in an actual thin-slab steel caster. The particles moved through the mold region with an asymmetrical distribution, which was caused by transients in fluid turbulence in the lower recirculation region, rather than by inlet variations at the nozzle port. Only about 8 pct of these small particles were removed to the top surface. This removal fraction was independent of both particle size and density, likely because all the simulated particles were too small to deviate significantly from the surrounding fluid flow. Finally, the computational results were further processed to predict the ultimate distribution of impurity particles in the solid thin slab after a short burst of inclusions entered the mold. They were reprocessed to reveal the distribution of total oxygen content for a steady inclusion supply from the nozzle. The results of this work confirm the important role of flow transients in the transport and capture of particles during continuous casting and can serve as a benchmark for future simplified models.

Flow control and operation monitoring system for individual spray nozzles

Abstract: An apparatus and process for monitoring fluid flow through a nozzle is disclosed. A vibration sensor, such as an accelerometer, is mounted to a nozzle. The vibration output received from the sensor is then analyzed to determine whether or not the nozzle is operating properly. Through the present invention, information can be obtained regarding variations in flow rate, and/or variations in spray pattern and droplet size spectra. If the nozzle flow pulsates, the vibration sensor may also provide information regarding whether the nozzle is pulsating according to a desired frequency duty cycle or waveform.

Numerical Prediction on the Characteristics of Spray-Induced Mixing and Thermal Decomposition of Urea Solution in SCR System

Abstract: The spray-induced mixing characteristics and thermal decomposition of aqueous urea solution into ammonia have been studied to design optimum sizes and geometries of the mixing chamber in SCR (Selective Catalytic Reduction) system. The cold flow tests about the urea-injection nozzle were performed to clarify the parameters of spray mixing characteristics such as mean diameter and velocity of drops and spray width determined from the interactions between incoming air and injected drops. Discrete particle model in Fluent code was adopted to simulate spray-induced mixing process and the experimental results on the spray characteristics were used as input data of numerical calculations. The simulation results on the spray-induced mixing were verified by comparing the spray width extracted from the digital images with the simulated particle tracks of injected drops. The single kinetic model was adopted to predict thermal decomposition of urea solution into ammonia and solved simultaneously along with the verified spray model. The hot air generator was designed to match the flow rate and temperature of the exhaust gas of the real engines. The measured ammonia productions in the hot air generator were compared with the numerical predictions and the comparison results showed good agreements. Finally, we concluded that the design capabilities for sizing optimum mixing chamber were established.© 2004 ASME

Computational and experimental study of turbulent flow in a 0.4-scale water model of a continuous steel caster

Abstract: Single-phase turbulent flow in a 0.4-scale water model of a continuous steel caster is investigated using large eddy simulations (LES) and particle image velocimetry (PIV). The computational domain includes the entire submerged entry nozzle (SEN) starting from the tundish exit and the complete mold region. The results show a large, elongated recirculation zone in the SEN below the slide gate. The simulation also shows that the flow exiting the nozzle ports has a complex time-evolving pattern with strong cross-stream velocities, which is also seen in the experiments. With a few exceptions, which are probably due to uncertainties in the measurements, the computed flow field agrees with the measurements. The instantaneous jet is seen to have two typical patterns: a wobbling “stair-step” downward jet and a jet that bends upward midway between the SEN and the narrow face. A 51-second time average suppressed the asymmetries between the two halves of the upper mold region. However, the instantaneous velocity fields can be very different in the two halves. Long-term flow asymmetry is observed in the lower region. Interactions between the two halves cause large velocity fluctuations near the top surface. The effects of simplifying the computational domain and approximating the inlet conditions are presented.

System and Method for Delivering Cryogenic Fluid

Abstract: According to an embodiment of the present invention, a cryogenic fluid delivery system includes a vessel containing a cryogenic fluid at a first pressure and a first temperature, a first heat exchanger coupled to the vessel for receiving the cryogenic fluid and cooling the cryogenic fluid to a second temperature, a first pump coupled to the first heat exchanger for pressurizing the cryogenic fluid to a second pressure, a second pump for pressurizing the cryogenic fluid to a third pressure, a second heat exchanger coupled to the second pump for cooling the cryogenic fluid to a third temperature, and a nozzle coupled to the second heat exchanger for delivering a jet of the cryogenic fluid toward a target.

Controlled dispensing of material

Abstract: The system includes a nozzle, a drive, a metering pump, a supply of material and a controller. The nozzle dispenses material into contact with one or more surfaces of a window sash. The drive relatively moves the nozzle with respect to the window sash along a path of travel defined by a perimeter of the window sash at controlled speeds. The metering pump delivers the material to the nozzle at controlled volumetric rates that correspond to the controlled speeds of relative motion between the nozzle and the sash. The supply of material delivers the material to the metering pump. The controller controls the relative motion between the window sash and the nozzle and controls the flow rate of material dispensed by the nozzle.