Double Nozzle Research Articles

English

Development and introduction of high capacity, precise, reliable and energy efficient machinery/equipment is the need for judicious use of inputs. Manufacturing of agricultural machinery in India is varied in nature and starts from village artisans, tiny units, cottage to small scale industries, organized tractor and agricultural machinery manufacturers including energy and processing machinery industry. Precision in application rates for higher input-use efficiency can be achieved only by improving the designs of the existing machinery/equipment. Precision index (PI) of machine/equipment is based on its capability to perform a given task in an accurate manner. It is a worthwhile attribute to compare the performance of different equipment and operations to enhance the productivity of a given farm. The purpose of study was to propose an index, that is, PI to select efficient and precise machine/equipment for the farmers. PI values were calculated for three types of machinery namely zero seed cum fertilizer drills, planters and spraying machines. It was concluded that drill Make 2, tested in the year 2004, was having the highest PI value, that is, 0.97 or 97% followed by drill Make 1 having PI value 0.95 or 95% tested in the same year. Drill Make 5 tested in the year 2013 was having minimum PI value, that is, 0.80 or 80%. PI value for happy seeder machine was 0.88 or 88%. During the testing of multi-crop planter in year 2014, the variability of doubling attribute was more, that is, 28% followed by missing having 20% value and produced influence on PI which was observed to be 0.83 or 83%. PI of semi-automatic and automatic potato planter was found to be 0.70 and 0.80, respectively. The value was not much satisfactory and could be ranked under average category. PI of electrostatic sprayer mounted with single as well as twin nozzle was observed to be the highest, that is, 0.89 followed by PI of air assisted sprayer with single and double nozzle, that is, 0.83 and 0.84, respectively. Key words: Precision index, zero till seed cum fertilizer drill, happy seeder, spraying machines, planting machines.

Simplicity in diesel combustion structure suggested from agreement of experimental results with similarity theory and simple spray flame model

The author proposed a combustion similarity theory among different sized diesel engines about thirty years ago. This theory predicts combustion becomes similar among different sized diesel engines, when similarity conditions are satisfied. The theory suggests that it may be possible to have better thermal efficiency in small engines designed similarly to the large size engines. The results of the numerical simulation show that the engines designed to have a shallow dish type combustion chamber with double side injection nozzles, which is typical for large size engines, have improved thermal efficiency than the typical small sized engines with deep dish with a center injection nozzle. The difference is mainly due to the cooling loss effect and the main combustion characteristics are similar between the two types of engine systems. On the other hand, the author and his colleagues have investigated the development of high-speed diesel combustion simulator based on the HTB-DECS model developed by Hiroyasu, et al. The results show that it simulates combustion well for the injection timings, rates and engine speeds with the same model constants for an individual engine. Additionally, there are simple tendency in the model parameters among different engines. The results suggest that there is a simple structure in diesel combustion, although it appears to be very complex in the phenomena.

Experimental evaluation of wall shear stress in a double contraction nozzle using a water mock-up of a liquid Li target for an intense fusion neutron source

Herein, the wall shear stress in a double contraction nozzle has been evaluated experimentally to produce a liquid lithium (Li) target as a beam target for intense fusion neutron sources such as the International Fusion Materials Irradiation Facility (IFMIF), the Advanced Fusion Neutron Source (A-FNS), and the DEMO Oriented Neutron Source (DONES). The boundary layer thickness and wall shear stress are essential physical parameters to understand erosion–corrosion by the high-speed liquid Li flow in the nozzle, which is the key component in producing a stable Li target. Therefore, these parameters were experimentally evaluated using an acrylic mock-up of the target assembly. The velocity distribution in the nozzle was measured by a laser-doppler velocimeter and the momentum thickness along the nozzle wall was calculated using an empirical prediction method. The resulting momentum thickness was used to estimate the variation of the wall shear stress along the nozzle wall. Consequently, the wall shear stress was at the maximum in the second convergent section in front of the nozzle exit.

Effect of the type of preparation and spraying parameters on zinc deposition on soybean plants

The aim of the research was to determine deposition of zinc on soybean plants sprayed in three development phases: 2, 4 and 6 specific leaves. The spraying involved the following parameters: speed was 0.86 m s−1, pressure: 0.20 and 0.28 MPa, standard nozzles: flat fan XR 110-02 and double flat fan DF 120-02. Soybean plants of Pollux variety were sprayed, with foliar fertilizer Mikrovit Zinc 112 and the preparation containing zinc nanoparticles. The dose of both preparations amounted 160 g Zn ha−1. After spraying, the plants were cut, dried, and mineralized. Zinc content in the samples was measured with atomic absorption spectrometer. The highest values of zinc deposition soybean plants were recorded DF 120-02 nozzle, regardless the spraying parameters, as well as soy development phase. The use of nanozinc and DF 120-02 nozzle in 4 leaves development phase caused higher values of zinc deposition 12.5% (0.20 MPa) and 15% (0.28 MPa), while in 6 leaves phase, the mentioned values increased by 13% (0.20 MPa) and 3.6% (0.28 MPa), as compared to the ones obtained for the foliar fertilizer. The highest values of nanozinc deposition using DF 120-02 nozzles were recorded at 0.20 MPa pressure: 179.1 mg kg−1 (2 leaves phase) and 178.0 mg kg−1 (6 leaves phase), as well as at 0.28 MPa pressure: 127.7 mg kg−1(4 leaves phase). In comparison with flat fan nozzle XR 110-02, the use of double flat fan nozzle DF 120-02 increased zinc deposition by 151, 110, and 90%, respectively. Statistical analysis of the test results showed a significant effect of the type of nozzle used for spraying on the value of zinc deposition on soybean plants.

Preparation and hemocompatibility of electrospun Bacteria Cellulose Sulfate/Polyvinyl Alcohol nanofibrous composite membrane

Bacterial cellulose sulfate (BCS)/poly(vinyl alcohol) (PVA) membrane (BCSm) was prepared through electrospinning BC sulfate together with PVA. To increase the stability of BCSm, BCS/PVA was electrospun together with ethyl cellulose by double nozzles to obtain composite membranes (BCSE). The membranes were characterized with SEM, water contact angles. The results of platelet adhesion experiment showed that the BCSE membrane with only nanofibers had good hemocompatibility.

The effect of coarse-droplet spraying with double flat fan air induction nozzle and spray volume adjustment model on the efficiency of fungicides and residues in processing tomato

The study was conducted for the purpose of improving the application of fungicides against potato late blight (Phytophthora infestans (Mont.) de Bary) (PLB) in processing tomato. The usability of coarse spray quality with double flat fan air induction IDKT12003 nozzle and the impact of fixed and variable spray volume and adjuvants during alternate application of azoxystrobin and chlorothalonil were analysed on the basis of plant infestation and fungicide residues. The variable spray volume was calculated based on the number of leaves on a plant. The study was conducted during three vegetation seasons. Spraying of plants with significantly flattened canopies during the peak of the fructification season using an IDKT12003 nozzle was as effective as in the case of fine spraying performed with an XR11003 nozzle and facilitated the increase of fungicides residue. In the case of plants with high-spreading canopy at the beginning of fructification, XR11003 nozzle favoured the reduction of PLB infestation. Both spray volume adjustment systems enabled the same level of protection of tomato against PLB, which could result from alternate application of systemic and contact fungicides. Polyalkyleneoxide modified heptamethyltrisiloxane adjuvant, which causes siginificant increase in wetting and droplet spreading, facilitated the reduction of tomato PLB infestation during the application of fungicides using an IDKT12003 nozzle.

Flow Characteristics of Double Serpentine Convergent Nozzle With Different Inlet Configuration

Serpentine nozzles have been used in stealth fighters to increase their survivability. For real turbofan aero-engines, the existence of the double ducts (bypass and core flow), the tail cone, the struts, the lobed mixers, and the swirl flows from the engine turbine, could lead to complex flow features of serpentine nozzle. The aim of this paper is to ascertain the effect of different inlet configurations on the flow characteristics of a double serpentine convergent nozzle. The detailed flow features of the double serpentine convergent nozzle including/excluding the tail cone and the struts are investigated. The effects of inlet swirl angles and strut setting angles on the flow field and performance of the serpentine nozzle are also computed. The results show that the vortices, which inherently exist at the corners, are not affected by the existence of the bypass, the tail cone, and the struts. The existence of the tail cone and the struts leads to differences in the high-vorticity regions of the core flow. The static temperature contours are dependent on the distributions of the x-streamwise vorticity around the core flow. The high static temperature region is decreased with the increase of the inlet swirl angle and the setting angle of the struts. The performance loss of the serpentine nozzle is mostly caused by its inherent losses such as the friction loss and the shock loss. The performance of the serpentine nozzle is decreased as the inlet swirl angle and the setting angle of the struts increase.

Additive manufacturing of laser cutting nozzles by SLM: processing, finishing and functional characterization

PurposeThe purpose of this paper is to demonstrate the use of selective laser melting for producing single and double chamber laser cutting nozzles. The main aim is to assess a whole production chain composed of an additive manufacturing (AM) and consecutive finishing processes together. Beyond the metrological and flow-related characterization of the produced nozzles, functional analysis on the use of the produced nozzles are carried out through laser cutting experiments.Design/methodology/approachSLM experiments were carried out to determine the correct compensation factor to achieve a desired nozzle diameter on steel with known processibility by SLM and using standard nozzle geometries for comparative purposes. The produced nozzles are finished through electrochemical machining (ECM) and abrasive flow machining (AFM). The performance of nozzles produced via additive manufacturing (AM) are compared to conventional ones on an industrial laser cutting system through cutting experiments with a 6 kW fibre laser. The produced nozzles are characterized in terms of pressure drop and flow dynamics through Schlieren imaging.FindingsThe manufacturing chain was regulated to achieve 1 mm diameter nozzles after consecutive post processing. The average surface roughness could be lowered by approximately 80 per cent. The SLM produced single chamber nozzles would perform similarly to conventional nozzles during the laser cutting of 1 mm mild steel with nitrogen. The double chamber nozzles could provide complete cuts with oxygen on 5 mm-thick mild steel only after post-processing. Post-processing operations proved to decrease the pressure drop of the nozzles. Schlieren images showed jet constriction at the nozzle outlet on the as-built nozzles.Originality/valueIn this work, the use of an additive manufacturing process is assessed together with suitable finishing and functional analysis of the related application to provide a complete production and evaluation chain. The results show how the finishing processes should be allocated in an AM-based production chain in a broader vision. In particular, the results confirm the functionality for designing more complex nozzle geometries for laser cutting, exploiting the flexibility of SLM process.

The effect of the type of preparation on the deposit of copper while spraying the winter oilseed rape

The aim of the research was to determine the copper deposit volume on winter oilseed rape in three development phase (according to the BBCH scale: 12, 14 and 16). The experiment was performed in triplicate at the spraying speed of 0.86 m s-1. Two working fluids were used: foliar fertilizer Mikrovit Copper 80 and a nanocopper preparation, at the dose of 160 g Cu ha-1. The deposition treatment of the plants was conducted in the spraying chamber ‘Aporo1’ at two pressures (0.20 and 0.28 MPa), using two different types of flat fan nozzles. The dried rape plants were mineralized, and then, in order to determine the deposit, the Cu element concentration was measured using the spectrometer. The largest deposit of copper was obtained using the foliar fertilizer Mikrovit Copper 80 and using a double flat fan nozzle DF 120-02. The statistical analysis of the results of the study showed a significant effect of the type of liquid used on the value of copper deposit on winter oilseed rape plants.

Experimental and Computational Exploration of Underexpanded Jets from Conical, Bell and Double Parabolic Nozzles

The flow structure of the jet emanating from supersonic nozzle with different profiles at underexpanded condition were investigated systematically. Experiments were carried out on conical, bell and double parabolic nozzle at Nozzle Pressure Ratios (NPR) of 4.5, 5 and 5.5. For the sake of comparison, the divergent length was the same for all the nozzles. Numerical simulations were also conducted in a two dimensional computational domain taking a density-based solver with RANS equations and SST k-ω turbulence model. The experimental and numerical results matched well all NPRs. The shock cell length, potential core length and supersonic core length at different NPRs were determined from experiments and compared to numerical predictions. These values are also compared to the predicted values based on the equations previously developed by researchers. It is observed that there is not much influence in nozzle profiles in the shock cell length, potential core length and supersonic core length.

Design of a double parabolic supersonic nozzle and performance evaluation by experimental and numerical methods

Purpose The purpose of this paper is to design a double parabolic nozzle and to compare the performance with conventional nozzle designs. Design/methodology/approach The throat diameter and divergent length for Conical, Bell and Double Parabolic nozzles were kept same for the sake of comparison. The double parabolic nozzle has been designed in such a way that the maximum slope of the divergent curve is taken as one-third of the Prandtl Meyer (PM) angle. The studies were carried out at Nozzle Pressure Ratio (NPR) of 5 and also at design conditions (NPR = 3.7). Experimental measurements were carried out for all the three nozzle configurations and the performance parameters compared. Numerical simulations were also carried out in a two-dimensional computational domain incorporating density-based solver with RANS equations and SST k-ω turbulence model. Findings The numerical predictions were found to be in reasonable agreement with the measured experimental values. An enhancement in thrust was observed for double parabolic nozzle when compared with that of conical and bell nozzles. Research limitations/implications Even though the present numerical simulations were capable of predicting shock cell parameters reasonably well, shock oscillations were not captured. Practical implications The double parabolic nozzle design has enormous practical importance as a small increase in thrust can result in a significant gain in pay load. Social implications The thrust developed by the double parabolic nozzle is seen to be on the higher side than that of conventional nozzles with better fuel economy. Originality/value The overall performance of the double parabolic nozzle is better than conical and bell nozzles for the same throat diameter and length.

Research on the Effect of Welding Speed on the Quality of Welding Seam Based on the Local Dry Underwater Welding

The repair of nuclear spent fuel pool has a high requirement for the quality of welding, the welding speed directly affects the quality of the weld when local dry automatic underwater welding is used to repair the damaged surface. Under the condition of the same condition, the local dry automatic underwater welding test was carried out under the condition of the same welding condition. Taking the 20cm as the experimental condition, after massive experiments show that when the welding speed is approximately 48cm/min the weld quality is high, meeting the design requirements, based on the double layer shrinkage nozzle chamber of local dry underwater automatic welding.

Internal flow and external jet characteristics of double serpentine nozzle with different aspect ratio

In order to increase the survivability of the fighter aircraft, the serpentine nozzle has been applied in series of stealth bombers and unmanned aerial vehicles due to its excellent potentiality of evidently suppressing the infrared radiation signatures and radar cross section emitted by engine exhausts. Among the geometric parameters of the serpentine nozzle, the aspect ratio (AR) at the nozzle exit is one of the most critical parameters for the nozzle design as the infrared suppression effect could be greatly enhanced with the increment of AR by strengthening the mixing between the exhaust plume and atmosphere; the aim of this paper is to study the influence of the AR on the flow characteristics of the double serpentine nozzle. The flow features of six double serpentine convergent nozzles, i.e. AR = 3, 5, 7, 9, 11, 15 respectively, were numerically simulated with the shear stress transport κ–ω turbulent model adopted, which had been validated by the experimental data. The characteristics of internal flow and external jet, and the aerodynamic performances of these six nozzles were compared. Results show that the Ma contours at the symmetric plane are different due to the distinct flow accelerations caused by the change of the curvature and the duct height for diverse AR, and the surface pressure and the shock wave features are different correspondingly. The lateral divergence and the lateral convergence characteristics of the nozzle configuration lead to opposite lateral flow under diverse AR, and the change of lateral width induced different lateral pressure gradient, then lead to various lateral vortex distributions. The length of potential core is the contribution of the comprehensive effects of geometry parameters, and it is decreased with the increase of AR due to the dominated effect of the increased mixing area; however, the declining rate is slowed down. The AR of 5 should be chosen for the best aerodynamic performance of the double serpentine nozzle under the qualifications to completely shield the high-temperature turbine.

Formic acid aggregation in 2D supersonic expansions probed by FTIR imaging.

C=O stretching vibrations of formic acid trimers are assigned on the basis of FTIR and Raman jet spectroscopy and further validated by an FTIR imaging study based on their aggregation behavior in supersonic expansions. The effect of shock waves on cluster formation and decomposition is probed by shifting them into the field of view of the focal plane array detector. A double slit nozzle is presented that merges two supersonic jets for a more localized study of such shock waves.

Influences of shield ratio on the infrared signature of serpentine nozzle

The criteria for designing the serpentine nozzle on the aspect of infrared suppression is undocumented currently. The aim of this paper is to investigate the influences of the shield ratio on the infrared signature of the serpentine nozzle. Firstly, a validation study was conducted to get the reliable computational method of the infrared signature. Then, the infrared signatures of the serpentine nozzles with variable shield ratios were investigated numerically, and the comparison between the serpentine nozzle and the circular nozzle was also conducted. Results show that 28.9% of the infrared radiation intensity, on average, can be reduced by the single serpentine nozzle, as compare with the circular nozzle. The shield ratio has little effect on the infrared signature of gas outside of the serpentine nozzle exit. And the completely shielded serpentine nozzle cannot bring the greatest benefit to the infrared stealth. The single serpentine nozzle with shield ratio of 0.75 and the double serpentine nozzle with shield ratio of 0.5 have better infrared stealth performance than the others. The visible area ratio can be used as an indicator to evaluate the infrared signature of the serpentine nozzle. In order to provide an effective infrared suppression, the visible area ratio of the single serpentine nozzle and the double serpentine nozzle should be restricted under 0.15 and 0.35, respectively.

Active flow control of bi-stable asymmetric vortices on a slender body by alternating synthetic jets

A synthetic jet actuator with double nozzles is developed to control the leeward vortices behind the slender body at a high angle of attack. Periodic alternating disturbance at the nose tip of the slender body is continuously provided by the alternating synthetic jets. A series of experiments is conducted in a low speed and low turbulence wind tunnel. The results show that the alternating synthetic jets at the nose tip can achieve a suitable control effect in which the lateral force is eliminated. For a very high angle of attack, the leeward vortices behind the slender body are in the inherently bi-stable state; in this state, the symmetric distribution formation by the leeward vortices is nearly impossible. However, the alternating disturbance of the nose tip can break the bi-stable state and transform it into other two states, which are the unsteady switched state of the leeward vortices and the quasi-steady symmetric state. Varying the control frequency significantly affects the state of the leeward vortex. In the range of the lower control frequency, the leeward vortices switch back and forth and follow the cycle of the alternating disturbance at the nose tip. In the range of the higher control frequency, the leeward vortices are in a stable symmetric distribution state. As the alternating disturbance frequency increases from lower to higher, the switched amplitude of the leeward vortices decreases and the unsteady switched state of the leeward vortices gradually changes to the quasi-steady symmetric state. This amplitude reduction occurs because the position of the leeward vortices is very sensitive to the alternating disturbance of the nose tip and is related to the inertia effect of the fluid.

Numerical investigation of gas-disperse jet flows created by coaxial nozzles during the laser direct material deposition

The paper presents the results of modelling of powder transport during the laser direct material deposition, involving standard coaxial nozzles made by Trumpf and Precitec and radiation of a СО2-laser with the power up to 4kW. The patterns of particle trajectories positions are shown in the space for various geometries of coaxial nozzles (the double and triple ones). It is shown that collisions of particles and walls of the transport channel impose the governing effect on the particle trajectories, geometry of the powder jet, and density of particle's distribution in the flow and on the substrate. Inelastic collisions with walls cause velocity decrease after the reflection, which has a positive effect on the powder flow profile and focusing. Heating of particles depends on the position of their trajectories and residence time in the high-intensity radiation area. It is also shown that the triple coaxial nozzle has wider options to control the gas-disperse flows than the double coaxial nozzle. The preferable position of the substrate, 20±5mm, is found by calculations; here, the focusing of the powder jet into the laser spot and heating of the super-alloy Ti-6Al-4V particles in the radiation field are optimal. The results can be used to improve the laser cladding and direct material deposition process.

Double-flow focused liquid injector for efficient serial femtosecond crystallography

Serial femtosecond crystallography requires reliable and efficient delivery of fresh crystals across the beam of an X-ray free-electron laser over the course of an experiment. We introduce a double-flow focusing nozzle to meet this challenge, with significantly reduced sample consumption, while improving jet stability over previous generations of nozzles. We demonstrate its use to determine the first room-temperature structure of RNA polymerase II at high resolution, revealing new structural details. Moreover, the double flow-focusing nozzles were successfully tested with three other protein samples and the first room temperature structure of an extradiol ring-cleaving dioxygenase was solved by utilizing the improved operation and characteristics of these devices.

Optimization of spray deposition and Tetranychus urticae control with air assisted and electrostatic sprayer

Improved spray deposition can be attained by electrostatically charging spray droplets, which increases the attraction of droplets to plants and decreases operator exposure to pesticide and losses to the environment. However, this technique alone is not sufficient to achieve desirable penetration of the spray solution into the crop canopy; thus, air assistance can be added to the electrostatic spraying to further improve spray deposition. This study was conducted to compare different spraying technologies on spray deposition and two-spotted spider mite control in cut chrysanthemum. Treatments included in the study were: conventional TJ 8003 double flat fan nozzles, conventional TXVK-3 hollow cone nozzles, semi-stationary motorized jet launched spray with electrostatic spray system (ESS) and air assistance (AA), and semi-stationary motorized jet launched spray with AA only (no ESS). To evaluate the effect of these spraying technologies on the control of two-spotted spider mite, a control treatment was included that did not receive an acaricide application. The AA spraying technology, with or without ESS, optimized spray deposition and provided satisfactory two-spotted spider mite control up to 4 days after application.

Three-Dimensional Numerical Analysis of LOX/Kerosene Engine Exhaust Plume Flow Field Characteristics

Aiming at calculating and studying the flow field characteristics of engine exhaust plume and comparative analyzing the effects of different chemical reaction mechanisms on the engine exhaust plume flow field characteristics, a method considering fully the combustion state influence is put forward, which is applied to exhaust plume flow field calculation of multinozzle engine. On this basis, a three-dimensional numerical analysis of the effects of different chemical reaction mechanisms on LOX/kerosene engine exhaust plume flow field characteristics was carried out. It is found that multistep chemical reaction can accurately describe the combustion process in the LOX/kerosene engine, the average chamber pressure from the calculation is 4.63% greater than that of the test, and the average chamber temperature from the calculation is 3.34% greater than that from the thermodynamic calculation. The exhaust plumes of single nozzle and double nozzle calculated using the global chemical reaction are longer than those using the multistep chemical reaction; the highest temperature and the highest velocity on the plume axis calculated using the former are greater than that using the latter. The important influence of chemical reaction mechanism must be considered in the study of the fixing structure of double nozzle engine on the rocket body.