Effect Of Nozzle Configuration Research Articles

Effects of Nozzle Configuration on Efficiency of Direct-Contact Gas-Vapor Mixture Generators

Effects of Nozzle Configuration on Efficiency of Direct-Contact Gas-Vapor Mixture Generators

Effect of nozzle configurations and jet orientations on thermal performance of jet impingement on convex surface

The present study analyze the thermal behaviour of multiple jets impinging on a convex heated surface for two different nozzle geometries (circular and elliptical) and its orientations. Tests are performed with 5 different nozzles at different values of non-dimensional nozzle to surface distance (z/d = 2–10) and Reynolds number (5000–28000). At smaller value of non-dimensional nozzle to plate distance, a distinct pattern of temperature variation is observed that depend on the nozzle shape and orientation, and this pattern diminishes as surface to nozzle distance increases. In the farthest region, elliptical nozzle is found to improve the uniformity (up to 60 %) in Nu variation compared to the circular jets even at the largest surface to nozzle distance. The overall heat transfer is found to increase up to 18 % and the uniformity is found to enhance up to 60 %) for N-2 and N-3 nozzles. An improvement in the thermal performance is observed in the elliptical nozzle in the fountain and impingement zones. The non-uniformity in the Nu behaviour is found to increase with the increase in Reynolds number.

Droplet spatial distribution of oil-based emulsion spray

Introduction Oil-based emulsion solution is a common pesticide formulation in agricultural spraying, and its spray characteristics are different from that of water spraying. The well understanding of its spray characteristics is the theoretical basis to improve the pesticide spraying technology. The objective of the present study is to deepen the understanding of the spray characteristics of oil-based emulsion. Method In this paper, the spatial distribution characteristics of spray droplets of oil-based emulsion were captured visually using the high-speed photomicrography. On the basis of image processing method, the droplet size and distribution density of spray droplets at different spatial locations were analyzed quantitatively. The effects of nozzle configuration and emulsion concentration on spray structures and droplet spatial distribution were discussed. Results Oil-based emulsion produced a special perforation atomization mechanism compared with water spray, which led to the increase of spray droplet size and distribution density. Nozzle configuration had a significant effect on oil-based emulsion spray, with the nozzle changed from ST110-01 to ST110-03 and ST110-05; the sheet lengths increased to 18 and 28 mm, respectively, whereas the volumetric median diameters increased to 51.19% and 76.00%, respectively. With emulsion concentration increased from 0.02% to 0.1% and 0.5%, the volumetric median diameters increased to 5.17% and 14.56%, respectively. Discussion The spray droplet size of oil-based emulsion spray can be scaled by the equivalent diameter of discharge orifice of nozzles. The products of volumetric median diameters and corresponding surface tensions were nearly constant for the oil-based emulsion spray of different emulsion concentrations. It is expected that this research could provide theoretical support for improving the spraying technology of oil-based emulsion and increasing the utilization of pesticide.

Effect of Nozzle Configuration and Ground Sprayer Speed on Fusarium Head Blight Management in Wheat

Fusarium head blight (FHB), caused primarily by Fusarium graminearum in the United States, is the most important disease of wheat in Kentucky and the surrounding region. In addition to reduced grain yields, grain quality also can be affected due to reduced test weights and contamination of harvested grain by associated mycotoxins, such as deoxynivalenol (DON). Although application of a foliar fungicide during the beginning anthesis growth stage is one of the primary practices used to manage FHB and DON, a major limiting factor in achieving greater efficacy has been fungicide coverage of wheat heads. This research evaluated different nozzle configurations and ground sprayer speeds for their effect on coverage of simulated wheat heads and management of FHB and DON in field trials conducted in 2017 to 2019 at the University of Kentucky Research and Education Center in Princeton, KY. Based on the results from this research, only minor differences in simulated wheat head coverage were observed across nozzle configurations and sprayer speeds. Depending on the nozzle configuration being used, applicators may need to adjust their sprayer speed to achieve maximum control of FHB.

Rapid velocity reduction and drift potential assessment of off-nozzle pesticide droplets

• Spatial velocities of off-nozzle droplets reduce by 50%–80% when falling 200 mm. • The diameter boundary of the droplet sensitive to the drift loss is about 150 μm. • The mechanism of velocity evolution differences between droplets is clarified. • The droplet diameter distribution is well improved by the modification of liquid. • Addition of adjuvant reduces the spatial drift loss of pesticide droplets by 20%–50%. The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying. Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle. The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.

Effects of Fluidic Oscillator Nozzle Angle on the Flowfield and Impingement Heat Transfer

Experimental and numerical investigations were performed to evaluate the effects of the exit nozzle configuration of a fluidic oscillator on the flowfield and impingement heat transfer performance downstream on a flat plate. A conventional wall-attachment-type fluidic oscillator with a fan-shaped exit configuration was studied. Eight different exit fan angles () were considered, and the effects of each nozzle configuration on the jet oscillation frequency, average fluid fan angle , and discharge coefficient were studied. Results show that the exit fan angle has a significant effect on the average fluid fan angle. Initially, increases along with the fan angle up to (); beyond which, eventually plateaus with further increase in . The jet oscillation frequency appears to be independent of nozzle configurations. A case study was performed that includes sweeping jet impingement heat transfer in order to assess the practical implication of the exit geometry. Heat transfer experiments were performed for each nozzle configuration at a jet-to-wall spacing of and three coolant mass flow rates (, 1.48, and ). The average heat transfer tends to deteriorate with increasing fan angle. However, a pronounced improvement in cooling uniformity was observed at large-fan-angle configurations (). The time-resolved velocity field obtained from an unsteady Reynolds-averaged Navier–Stokes simulation revealed that separation bubble starts to appear at the diverging wall of the nozzle exit when that prevents the lateral motion of the jet, thus reduces the average fluid fan angle.

The effect of nozzle configuration on the evolution of jet surface structure

The evolution of jet surface structure plays a key role in various atomization related applications. In this paper, the jet surface structures of two different nozzle configurations are captured and measured based on high-speed microscopic photography and a novel image processing method. Results show that the primary wavelength of surface wave decreases exponentially with Weber number and increases linearly with streamwise distance for both two nozzles. The primary wavelength that non-dimensionalized with boundary layer thickness is almost a constant for the same nozzle, but obviously different for different nozzles. The nozzle configuration has a significant effect on the scale of the surface structure when the Weber number is smaller than 50, however, this effect is limited for bigger Weber number.

Effects of Nozzle Configuration on Rock Erosion Under a Supercritical Carbon Dioxide Jet at Various Pressures and Temperatures

The supercritical carbon dioxide (SC-CO2) jet offers many advantages over water jets in the field of oil and gas exploration and development. To take better advantage of the SC-CO2 jet, effects of nozzle configuration on rock erosion characteristics were experimentally investigated with respect to the erosion volume. A convergent nozzle and two Laval nozzles, as well as artificial cores were employed in the experiments. It was found that the Laval nozzle can enhance rock erosion ability, which largely depends on the pressure and temperature conditions. The enhancement increases with rising inlet pressure. Compared with the convergent nozzle, the Laval-1 nozzle maximally enhances the erosion volume by 10%, 21.2% and 30.3% at inlet pressures of 30, 40 and 50 MPa, respectively; while the Laval-2 nozzle maximally increases the erosion volume by 32.5%, 49.2% and 60%. Moreover, the enhancement decreases with increasing ambient pressure under constant inlet pressure or constant pressure drop. The growth of fluid temperature above the critical value can increase the enhancement. In addition, the jet from the Laval-2 nozzle with a smooth inner profile always has a greater erosion ability than that from the Laval-1 nozzle.

Influence of nozzle configuration on the flow field of multiple jets

Turbulent jet flows with multiple nozzle inlets are investigated computationally using OpenFOAM. The configurations vary from single to five axisymmetric nozzles. First-order closure is used with Reynolds-averaged Navier–Stokes equations. Computed results are compared with the available experimental data. The effect of nozzle configuration on the jet flow field is discussed with predicted mean flow and turbulent flow data. Near-field of multiple jets shows the nonlinear behavior. Multiple jets show better performance in the near-field based on entrainment, secondary flows, and area-averaged turbulent kinetic energy. The downstream evolution of the multiple jets differs for configurations with and without central jet. The shape parameter confirms the evolution of the multiple jets towards an axisymmetric jet.

Effects of nozzle configuration on internal flow and primary jet breakup of flash boiling fuel sprays

Fuel spray plays more vital role in governing fuel economy and emission quality of IC engines due to the wide application of direct injection system in automotive engines. High temperature fuel spray, namely flash boiling spray, has been documented to improve fuel atomization and evaporation with less energy consumption compared with high pressure fuel spray. It is because the hot exhaust gas and coolant are two potential energy sources can be used to heat the fuel. Most of existing research works of flash boiling spray focus on investigating the spray behavior outside the nozzle, and limited studies can be found about the in-nozzle superheated flow. In this study, a two-dimensional transparent slit nozzle was designed to reveal the in-nozzle flow under various superheated conditions. Both internal flow and near-nozzle fuel jet were investigated using high-speed backlit imaging technique to acquire a better understanding of the primary breakup process of flash boiling sprays. The slit thickness was 40μm with well-adjusted nozzle length and inlet corner radius to investigate the effects of nozzle configuration. The ambient pressure ranged from 40kPa to 190kPa, and fuel temperature varied from 41°C to 71°C, which produced a wide range of superheated conditions. N-pentane was chosen as test fluid with an injection pressure of 0.6MPa. Experimental results showed that the bubbles occurring inside the nozzle near the nozzle exit affected the near-nozzle fuel jet characteristics. Stronger superheated conditions resulted in larger in-nozzle bubbles, which facilitated the jet break-up process significantly. Longer nozzle and nozzle with sharp inlet corner led to larger inner bubble volume fraction and narrower liquid core of near-nozzle fuel jet. In summary, the effects of nozzle configuration on in-nozzle flow and near-nozzle fuel jet were revealed with more fundamental understanding of the primary breakup process of flash boiling sprays.

ノズル形態が極超音速航空機の離陸騒音に及ぼす影響

Effect of nozzle configuration on the takeoff noise of a hypersonic transport is investigated based on small-scale nozzle experiments. In the Japan Aerospace Exploration Agency, the precooled turbojet (PCTJ) engine aimed at the hypersonic flight is under development. The takeoff noise of the full-scale vehicle is assessed before it is put into the operation using an acoustic simulation method. By matching the jet velocity and jet Mach number with the realistic PCTJ engine condition, the acoustic characteristics of the hypersonic nozzle are duplicated with a small-scale nozzle model. The jet noise database around the hypersonic nozzle is established through a number of experiments, and by taking into account 1) the nozzle scale, 2) the number of nozzles, 3) the direction of installation, 4) the measurement distance and angle based on the flight trajectory, and 5) the atmospheric absorption, the effective perceived noise level (EPNL) at the flyover point is calculated. It is shown that the nozzle configuration has a large impact on the takeoff noise, and that such an assessment could contribute to the improvement of the integration design of the vehicle.

The Effect of Nozzle Configuration on Characteristics of Fluidic Excited Jets

Using fluidic self-excited jets increases the rate of fluid mixing and reduces fuel consumption in industry burners (torches) and combustion chambers. The geometry of such jets is an important factor for fluidic jet determination. This study is concerned with investigating the types of fluidic nozzles configuration. The effect of nozzle configuration types was studied on various parameters such as frequency, velocity profile, velocity decay rate, the half angle of jet spread, and entrainment ratio. Maximum frequency and excited oscillation amplitude of fluidic jets were observed in the original geometry configuration. Also, the maximum spread rate and minimum velocity profile were observed in this geometry. Velocity decay rate shows its maximum magnitude in the original geometry configuration. Turbulence intensity reaches its maximum value in this geometry without any internal nozzle, whereas it shows the minimum value at geometry with an additional wall along the internal nozzle. The maximum increase in the half angle of jet spread was seen in the original geometry configuration. In this geometry, entrainment ratio is less than one, while in the geometry to create steady jets, entrainment ratio is more than one.

Erosion Experimental Study on Organ-Pipe Nozzles in Air

Experiment of aluminum block erosion using organ-pipe nozzle was carried out in air. The erosion effects of water jet were used to evaluate the performance of organ-pipe nozzle. The experiment and corresponding data were used to analyze the effects of nozzle configuration, jet pressure, standoff distance. Results have shown that the organ-pipe water jets are much more effective in aluminum block erosion.

喷管构形和聚焦位置对雾化水滴推进性能的影响

喷管构形和聚焦位置对雾化水滴推进性能的影响

Effect of Nozzle Configuration on Cooling of a Hot Moving Steel Plate

The objective of this study is to develop an experimental database for modelling boiling heat transfer that occurs during run-out table cooling. Experiments have been carried out on a pilot scale run-out table with an emphasis on the effect of nozzle configuration on the overall heat extraction rate. The heat extraction capability of an individual nozzle is generally determined by the surface temperature of the to-be-impinged and surrounding areas of the steel plate to be cooled. Nozzle arrangements of subsequent jet lines with respect to hot and cold regions developed by prior jet line impingement is crucial inmaintaining uniform and efficient cooling of the hot plate or strip. Results from a series of tests are presented and discussed to examine quantitatively heat extraction for a moving steel plate as a function of nozzle configuration.

Effect of Nozzle Configuration on Cooling of a Hot Moving Steel Plate

Effect of Nozzle Configuration on Cooling of a Hot Moving Steel Plate

Effect of nozzle geometry on pressure drop and heat transfer in submerged jet arrays

In the area of concentrating photovoltaics, where replacing expensive solar cell area by less expensive concentrator material is used as a way of reducing costs, one of the principal concerns is excessive heating of the photovoltaic cells. If the cells are not cooled efficiently, an elevated cell temperature can dramatically reduce their efficiency and can also lead to irreversible cell damage. In addition, there is a need for a cooling system which delivers a high rate of cooling at a minimum pumping power requirement. Liquid jet impingement is a promising method for this purpose because of its potential for very high heat transfer coefficients [1]. This technology is widely used in areas such as the thermal treatment of metals, cooling of internal combustion engines and thermal control of high power density electronic devices [2]. Various aspects of jet impingement such as the effect of Reynolds number, Prandtl number, nozzle-to-plate spacing, nozzle pitch and nozzle geometry have been studied extensively. Comprehensive literature reviews on jet impingement in generalare given by Martin [3], Webb and Ma [2] and Han and Goldstein [4]. This technical note deals specifically with the effect of nozzle configuration in submerged, confined jet arrays. Several other studies have investigated the effect of nozzle geometry on the Nusselt number of impinging jets. Lee and Lee [5] compared the heat transfer characteristics of

Effects of Nozzle Configuration on Flow Characteristics inside DC Plasma Torch

The effects of nozzle configuration on the characteristics of flow inside DC arc plasma torches are investigated by numerical simulation. The plasma torches with three typical types of nozzle configuration are used in this paper, and these torches are the SG-100 series commercial products of PRAXAIR Thermal Spray Products Inc. The assumption of steady-state, axis-symmetric, local thermodynamic equilibrium, and optically thin plasma is adopted in a two-dimensional modeling of plasma flow inside a plasma torch. The PHOENICS software is used for solving the governing equations, i.e., the conservation equations of mass, momentum, and energy. The calculated arc voltages are consistent with the experimental results when arc current, gas inflow rate, and working gas are the same. Temperature, axial velocity contours inside the plasma torches, and profiles along the torch axis and at the outlet section are presented to show the plasma flow characteristics. Comparisons are made among these torches in detail and the results show that torches with different anode nozzle configurations produce different characteristic plasma flows.

The effect of nozzle configuration on stagnation region heat transfer enhancement of axisymmetric jet impingement

The effect of nozzle configuration on stagnation region heat transfer enhancement of axisymmetric jet impingement

Effect of Nozzle Configuration, Gas Pressure, and Gas Type on Coating Properties in Wire Arc Spray

Wire arc spraying is a coating process in which minor modifications of the configuration and spray parameters can have a strong impact on coating characteristics. A study on the effects of the fluid dynamics of the atomizing gas on the coating properties is presented. Different types of nozzles, shrouds, and gases have been used to provide various flow velocities and reactive environments in the metal atomization region. The effects on particle velocity, coating density, composition, and interface characteristics between the coating and the substrate have been evaluated. It is clear that higher gas velocities improve practically all coating properties, but also increase oxide content in the coating. However, the oxidation can be drastically reduced if nonoxidizing gases are used for atomization in combination with a shroud. A discussion on the physical effects contributing to the observed adhesion improvements and interfacial properties is provided.