Nozzle Opening Research Articles

Computational and Investigational Proportional Flow Study on Cd Nozzle

As part of our study , we had to design, produce, and test a convergent-divergent type nozzle with a specific area ratio. The goal of this project is to replicate the operation of a converging-diverging nozzle, which is possibly the most significant and fundamental piece of engineering hardware involved with propulsion and high-speed gas flow.For this, we first examined a specific area ratio. Three distinct designs are constructed for the given area ratio (convergent, divergent, and convergent divergent).The flow through the nozzle is analysed under various back pressure situations. Then, using the values obtained from the analysis, we constructed the nozzle and evaluated its operation. We also tested the choke conditions under varied back pressures and the mass flow rate that corresponds to it. Finally, we plotted the curve of mass flow rates vs. pressure distribution with practical values. Thus, with the assistance of our department faculty, we successfully accomplished this assignment.

ANALYSIS OF THE AMMONIA ABSORPTION PROCESS FROM AIR FOR DISPERSED WATER CURRENTS GENERATED BY BETE TF 6NN AND TF 8NN SPIRAL NOZZLES

The work presents the absorption rate constant of ammonia into water using a station with spiralnozzles. In the research a station was employed with a chamber measuring 1 m x 1 m x 1 m withequipment enabling the regulation of ammonia concentration and nozzle operating parameters,as well as an ammonia concentration measurement system. In the first part of the research, thespraying characteristics of selected spiral nozzles were determined at pressures of 2 bar and 3 bar.For selected nozzle operating parameters, ammonia absorption tests were carried out at variousinitial concentration values: 250 ppm, 500 ppm, 1000 ppm. Based on the collected results, thenozzle characteristic p(Q), the distribution of the nozzle spray intensity in the SUFER program, theammonia concentration curve as a function of water supply time and the absorption rate constantwere determined.

Pelton turbine jet flow investigations using laser Doppler velocimetry

Hydropower is a sustainable and clean renewable energy source. The Pelton turbine is an impulse type of hydraulic turbine and operates under high head and low discharge. It comprises an injector, which converts high-pressure water into kinetic energy as a high-speed free surface water jet that impinges on the runner generating power coupled with an electric generator. The water is highly accelerated in the nozzle, which produces turbulent kinetic energy in the jet flow. Before impinging on the runner, the surrounding air is entrained into the jet, which causes the jet dispersion. The effective conversion of water energy into mechanical energy and the quality of a jet depend significantly on the uniformity of the jet. However, the jet encounters instabilities and non-uniformity caused by secondary flow and turbulence. Jet surface and velocity distribution do not remain symmetric. Investigation of the jet's velocity profile and turbulence intensities is important to understand the flow behavior and improvements in the design of injector. In this study, the experimental investigation of the jet has been performed using the laser Doppler velocimetry (LDV) system. The turbulent intensity and instantaneous velocity of the jet are analyzed at different locations along the jet flow. The velocity wake zone occurs around the center of the jet, which diminishes in the axial direction of the jet, with non-dimensional jet velocities values 0.91, 0.92, and 0.94 at x/Do of 0.5, 1, and 2 for ∼98% nozzle opening. The secondary flow velocity magnitude is larger for 90°–60° injector jet flow than for 90°–50°. The jet velocity profile obtained from the LDV has been compared with computational fluid dynamics analysis.

Improving spray performance of vehicle disinfection systems in livestock farms using computational fluid dynamics analysis

Effective vehicle disinfection systems (VDSs) are crucial in livestock-related industries to prevent the spread of diseases. This study aimed to improve the nozzle arrangement and operation of VDSs using computational fluid dynamics (CFD) simulations. The CFD simulations were conducted for two types of systems (simple and tunnel) which are commonly installed at farm entrances, and five vehicle types, including sedans, SUVs, cargo trucks, box trucks, and feed trucks. The results demonstrated significant improvements in the disinfection coverage and uniformity. For the simple-type VDS, the existing system exhibited low disinfection coverage on the wheels, top, and rear sections of vehicles; however, the modification of the nozzle positions and angles improved the coverage and uniformity. Additionally, increasing the number of nozzles and spray volume resulted in a 36–48 % increase in coverage across the vehicle entire surface. The tunnel-type VDS exhibited excessive disinfectant spray, leading to surface runoff and uneven coverage at the wheels and rear sections. This excessive disinfectant usage was reduced by 17 % by adjusting the nozzle arrangements and reducing spraying time by 5 s, while maintaining comparable coverage and uniformity. These findings highlight the importance of enhanced nozzle design and spray volume for effective vehicle disinfection. Livestock-related industries can enhance biosecurity measures and mitigate disease transmission risks by implementing the proposed improvements.

Simulating droplet distribution characteristics for sprinkler irrigation with a modified ballistic model

The ballistic model, with its high computational efficiency and small test workload, is an effective method to simulate the distribution of spray droplets. It can be employed to solve the problems of oversimplifying the droplet crushing process and motion shape and ignoring the droplet energy characteristics in the equivalent droplet indicator in the existing model assumptions. Based on the law of the motion of sprinkler irrigation water flow, the model assumption of continuous motion and segmental fragmentation of the jet is proposed in the current study. Ellipsoidal droplet shape parameters were introduced to construct the equations of the motion of sprinkler irrigation water flow in the jet and droplet stages, respectively. The critical conditions for large droplet separation and correction drag coefficient for small droplets are defined and solved, and the calculation formulas based on the energy-weighted equivalent droplet indicators were derived. The accuracy of the model was verified using 50PYC, ZY-2, and HY50 nozzles, and the modified model was compared with Fukui’s and Li’s models. The effects of working pressure, nozzle diameter, nozzle elevation angle, and installation height on the droplet landing distance, velocity, and angle at the end of the spray range were investigated. The results showed that: (1) The mean absolute error (MAE) and root-mean-square error (RMSE) of droplet landing distance, velocity, and angle under different working conditions simulated by the modified model were smaller than those obtained using Fukui’s and Li’s models, showing better simulation accuracy. Considering the simulated values of droplet landing distance, velocity, and angle of the 50 PYC nozzle (nozzle diameter of 22 mm and working pressure of 0.35 MPa) as an example, the accuracy of the modified model was improved by 72.86 % and 53.45 % (landing distance), 35.86 % and 70.57 % (landing velocity), 42.10 % and 67.66 % (landing angle) compared with the Fukui’s and the Li’s models, respectively. (2) Fukui’s and Li’s models demonstrate higher accuracy in simulating the droplet landing distance of the ZY-2 nozzle with a smaller nozzle diameter (7 mm) than in simulating the HY50 and 50PYC nozzles; (3) The changes in nozzle operating pressure, nozzle diameter, and nozzle elevation angle exert the greatest effect on the droplet landing distance, landing velocity, and landing angle, respectively. This study provides a novel idea for using the ballistic model to simulate the spray droplet distribution.

Design and Test of a Tree-Whitening Machine Based on a Multi-Nozzle Holder

In this study, a tree-whitening machine was designed based on the collaborative operation of multiple spray nozzles. This research utilized infrared ranging, ultrasonic detection, and spraying devices in order to realize the accurate spraying of trees and improve the efficiency and quality of spraying. The test results show that the working efficiency of the machine is 300 trees/h, the spraying coverage is up to 96.5%, and the applicable trunk circumference range is 500–1250 mm, which is more advantageous than the American UltraMaxII695 high-pressure electric spraying machine, the domestic HT20 machine, etc. Furthermore, it improves the working efficiency by 7.1%, the spraying coverage by 6.7%, and the expansion of the adaptable trunk circumference range by 20%, as well as having further advantages.

Multipurpose optimization of fuel injection parameters for diesel engine using response surface methodology

The hike in fuel prices and rapid depletion of fuel reserves have compelled scientists to focus on energy conservation, environmental protection, engine performance improvement, and cost saving. The prime objective of the study is to compare the empirical results with response surface methodology (RSM) optimized results in order to check the accuracy of model designed by RSM. Therefore, the current study examines the effect of fuel injection parameters (nozzle opening pressure and protrusion) on diesel engine performance and exhaust emissions. RSM technique was applied to predict engine performance and exhaust emission parameters along with their optimization. The brake thermal efficiency (BTE) was incremented by 1.23 % for protrusion from 1.5 to 2.5 mm under 240 bar nozzle opening pressure (NOP). BTE was increased by 0.94 and 4.51 % for 1.5 and 2.5 mm protrusion respectively. CO emission was decremented by 4.47 and 11.31 % for 1.5 and 2.5 mm protrusion respectively when the NOP changed from 230 to 240 bar. RSM model optimized input conditions 240 bar pressure, 2.5 mm protrusion, and 1935.67 engine rpm. The engine was again tested on RSM-optimized conditions and the highest absolute percentage error (APE) of 4.42 % was obtained for NOx emission, while the lowest APE of 2.89 % was obtained for BSFC.

Numerical Simulation of Erosion in Pelton Spear Valve at Different Openings

The spear valve is one of the most eroded hydro-mechanical components of the Pelton turbine operating in sediment-laden conditions. The spear valve is used to regulate or control the flow. In a multi-nozzle system, though having the same design, the spear valves show varying erosion patterns and intensities. The only difference was found to be the openings of the nozzle/spear valve. This demonstrates that there is some sort of connection between the nozzle opening and the erosion of the spear valve. The difference in erosion intensity in different spear valves can be seen on the site but the underlying phenomenon behind the erosion needed to be studied numerically. In this research, erosion patterns were numerically investigated using an open-source CFD tool, OpenFOAM. For this simulation, the sediment particles and their properties were incorporated into the flow using the built-in Lagrangian library of the OpenFOAM. To investigate the erosion in real time, a transient simulation was undertaken for various nozzle openings. This study only focuses on the erosion at the tip of the spear valve neglecting other parts of the nozzle. This study demonstrates that the erosion in the tip of the spear valve increases with the restriction in flow.

Experimental Investigation on Effect of Hoop Thickness on Performance of Hooped Pelton Wheel

A recent improvement in Pelton runner design, the hooped runner, is based on a redistribution of behaviour among the buckets and hoops and which allows stresses to be minimized and efficiency is nearly equivalent to conventional Pelton Runner apart from low nozzle opening of 40% and 60%. This advanced design having a couple of superiority from the mechanical orientation as well as from the assembly point of view without any different difficulty from the hydraulic orientation that establishes the significance of this unique concept. In the present work, an actual laboratory-scale hooped Pelton runner is developed. The thickness of its hoop is varied as 2 mm, 3 mm and 4 mm and to prove the competence of this advanced design and the influence of hoop thickness on the hydraulic performance of the Pelton wheel, detailed experimental studies have been performed. From the results it has been concluded that the power output and efficiency of hooped Pelton runner are nearly the same as the conventional Pelton runner at all nozzle opening.

Propulsion Aerodynamics for a Novel High-Speed Exhaust System

Abstract A key requirement to achieve sustainable high-speed flight and efficiency improvements in space access lies in the advanced performance of future propulsive architectures. Such concepts often feature high-speed nozzles, similar to rocket engines, but employ different configurations tailored to their mission. Additionally, they exhibit complex interaction phenomena between high-speed and separated flow regions at the base, which are not yet well understood. This paper presents a numerical investigation on the aerodynamic performance of a representative, novel exhaust system, which employs a high-speed nozzle and a complex-shaped cavity region at the base. Reynolds-Averaged Navier–Stokes computations are performed for a number of nozzle pressure ratios (NPRs) and freestream Mach numbers in the range of 2.7 < NPR < 24 and 0.7 < M∞ < 1.2, respectively. The corresponding Reynolds number lies within the range of 1.06 × 106 < Red < 1.28 × 106 based on the maximum diameter of the configuration. The impact of the cavity is revealed by direct comparison to an identical noncavity configuration. Results show a consistent trend of increasing base drag with increasing NPR for both configurations, owing to the jet entrainment effect. Cavity is found to have no impact on the incipient separation location of the nozzle flow. At conditions of M∞ = 1.2 and high NPRs, the cavity has a significant effect on the aerodynamic performance, transitioning nozzle operation to underexpanded conditions. This results in approximately 12% higher drag coefficient compared to the noncavity case and shifts the minimum NPR required for positive gross propulsive force to higher values.

Numerical investigation of the non-equilibrium condensation inside a fuel cell turbine with variable geometry

A turbine with variable geometry can fully recover energy from the fuel cell exhaust gas and effectively reduce parasitic power consumption of the compressor. In this study, an electric turbocharger is developed for a 100 kW fuel cell system. To investigate condensation occurring inside the turbine, a wet air condensation model based on a classical nucleation theory and the Hertz-Knudsen droplet model is proposed. Validation of the model is made by testing aerodynamic performances of the turbine. In order to do this, an air humidification bench is built and exhaust gas from the fuel cell cathode outlet is replaced by humidified high-pressure air. Numerical simulation and experiment results are in good agreement. Influences of nozzle vane angle and wall temperature of the turbine on its aerodynamic performances are examined. Results show that when the nozzle opening turns small, flow capacity of the turbine decreases, pressure at the nozzle outlet declines, and condensation is more likely to occur in the rotor area. As the wall temperature drops, area in which water vapor condenses rapidly moves forward from the rotor to the nozzle. Liquid water mass fraction at different locations increases approximately 5 % as the wall temperature decreases from 310 K to 290 K.

INFLUENCE OF GEOMETRIC PARAMETERS OF SUPPORT-DISTRIBUTION GRIDES
 ON HYDRODYNAMICSIN A MASS EXCHANGER WITH A MOVABLE BALL NOZZLE

In the chemical industry, as well as in the petrochemical, construction, metallurgical, mining and chemical and
 other industries, packed and tray columns are used for the mass transfer process. This paper provides a brief introduction
 to packed columns and their applications. The principle of operation of movable nozzles is outlined, as well as
 their main disadvantages. An experimental absorption column is described and a technique for conducting experimental
 studies is described. Based on the results of the experiments, graphs of the dependence of the hydraulic resistance
 of the support-distribution grids on the gas velocity, as well as movable ball nozzles using these grids, both
 with and without irrigation, were plotted.

Effect of Y-jet nozzle geometry and operating conditions on spray characteristics and atomizer efficiency

The investigation and optimization of the atomizer nozzle design are paramount for an efficient atomization performance. Motivated by internal mixing atomizers used in FCC-reactors in the oil industry, the present work aims to improve the gas-liquid mixing process promoted by a specific design of the Y-jet nozzle by investigating the impact of key geometric parameters. The performance assessment is conducted by investigating the internal mixing chamber pressure, high-speed images of the spray, and the analysis of droplet size and velocity spatial distributions. The investigation considers industrially representative operating conditions as opposed to the lower mass flow rates typically employed in lab-scale investigations. The geometry variation considers the length and opening angle of the internal mixing chamber, as well as the impingement angle between the gas and the liquid jets inside the atomizer nozzle. A particular geometric characteristic of the utilized nozzles is the mixing-chamber conical geometry, distinguishing them from conventional cylindrical geometries. The impact of the nozzle geometry and operation parameters on atomization efficiency and spray homogeneity are the main outcomes of this approach. Overall, nozzles with shorter mixing chambers promote more efficient atomization combined with small droplet sizes and a more homogeneous spray.

Numerical simulation of gas dynamics during operation of a wide-range rocket nozzle with a porous insert

Numerical simulation of gas dynamics during operation of a wide-range rocket nozzle with a porous insert

Numerical investigation on expansion–deflection nozzle flow during an ascending–descending trajectory

The flow characteristics of an annular expansion–deflection (ED) nozzle are investigated numerically during an ascending–descending trajectory over a large nozzle pressure ratio span. The shock pattern evolution, nozzle operation mode transition, nozzle flow hysteresis, and thrust variation during this trajectory are examined, and the interactions between them are discussed. A new criterion for distinguishing the open and closed wake modes of the ED nozzle is proposed based on a perturbation front in combination with sonic lines. Using this criterion, an exact boundary between the open and closed wake modes can be readily drawn. The present study shows that the interaction between the shock pattern transition and nozzle operation mode transition is indirect. During the ascent, the open-to-closed wake mode transition lays the foundation of the downstream shock pattern variation. During the descent, however, the stretching of the dominating Mach stem delays the nozzle closed-to-open wake mode transition. The different flow mechanisms during the ascent and descent result in an overall hysteresis of nozzle operation mode transition. The nozzle thrust undergoes dropping-rising developments (the thrust troughs) in the ascent and descent. These thrust troughs are also found to be the results of two very different flow mechanisms, namely, the forward–backward movement of shock separation point on nozzle shroud and the pressure rise on pintle base after closed-to-open mode transition.

Study on the Cooling Effect of Double-Layer Spray Greenhouse

Greenhouses provide suitable environmental conditions for plant growth. Double-layer plastic greenhouses are often used in many regions to ensure normal crop growth during winter since single-layer plastic greenhouses have poor insulation. However, during summer, the high insulation of double-layer plastic greenhouses, combined with excessive external solar radiation, can cause high temperatures inside the greenhouse that are not suitable for plant growth and require cooling. In this study, we propose a double-layer spray greenhouse using a high-pressure spraying system that is placed inside the double film that allows for additional cooling capacity during the summer in order to sustain plant growth. A greenhouse platform test was set up to investigate the optimum operating conditions for the nozzles and to explore changes in greenhouse microclimate under different nozzle operating conditions. The results show that (1) the cooling rate increases with increasing water supply pressure, nozzle diameter and spraying time, and the humidification rate is consistent with the change in the rate of cooling. (2) The optimal condition for cooling in this experiment is achieved with a 120° double nozzle with a nozzle diameter of 0.30 mm, a water supply pressure of 6 MPa, and a spraying time of 15 min, which can reduce the temperature by up to 5.36 °C and serve as a reference for the summer cooling of the double-layer greenhouse.

Modeling and experimental studies on chemical absorption of ammonia emitted from poultry manure during the drying process by a wet spray scrubber: Optimization by Box-Behnken design

One of the most important environmental worries related to poultry production is ammonia gas emission which is affected by poultry manure moisture. This research was aimed at investigating poultry manure drying in a hot air dryer and its influence on ammonium nitrogen losses to provide an overview of ammonia gas emissions and absorption of emitted ammonia by a spray scrubber. The effect of air temperature (60–80 °C), air relative humidity (8–18 %), manure depth (2–4 cm), and air velocity (2–3 m s−1) were analyzed to optimize the drying process. The optimization of ammonia absorption involved analyzing the effects of absorbent solution temperature (30–50 °C), solution pH (2−4), and nozzle operating pressure (0.2–0.6 Mpa). The Box–Behnken design was applied to optimize these processes. Manure depth was the factor that had the most significant effect on both drying duration and ammonia emission (ammonium nitrogen losses). during the drying process, the ammonium nitrogen losses increased with increasing the manure depth and decreasing the air velocity and air temperature. The optimum ammonium nitrogen was 570,330 mg h lit−1 at an air temperature of 60 °C, air relative humidity of 8.11 %, manure depth of 3.95 cm, and air velocity of 2 m s−1. Both the temperature of the absorbent solution and the solution pH had opposite effects on the ammonia absorption. Increasing nozzle operating pressure increased ammonia absorption. The maximum ammonia absorption was obtained at a solution temperature of 49.2 °C, solution pH of 2, and nozzle operating pressure of 0.58 Mpa. At these conditions, the amount of ammonium sulfate in the absorbent solution was 9.09 g lit−1 and the efficiency of the spray scrubber was 66.79 %. So, we can be sure that ammonia emission from poultry manure and the absorption of emitted ammonia can be controlled by varying the investigated variables.

Redesigning TBM-1.7 Combustion Unit to Expand the Temperature Range

It is shown that the transition to a new low-temperature method of convective drying leads to a reduction in grain drying costs.The implementation of this method is confirmed to require expanded temperatures generated by the TBM-1.7 furnace unit that the SZSh-16A shaft dryer is equipped with. It is noted that a plant-manufactured burner nozzle works smoothly only when the fuel consumption is 40-100 kilograms per hour, and the air heating temperatures are 50-130 degrees Celsius. (Research purpose) To determine the jet optimal parameters for smooth operation of the nozzle in the TBM-1.7 combustion unit working on the liquid fuel at the extended air heating temperatures of 15-130 degrees Celsius. (Materials and methods) The designs of four types of jets were studied on the burner nozzle of the TBM-1.7 combustion unit. In total, the operation of 160 jets was examined. The jets were made of steel. They differed in the number of holes, their length, diameter, the availability of threads. (Results and discussion) It is determined that the nozzle smooth operation is provided only by jets with threaded holes, whose optimal length is 4 millimeters. The air heating temperature of 15-25 degrees Celsius is provided by M3 four-hole jet, and the temperature of 25-40 degrees Celsius is provided by M4 three-hole jet. (Conclusions) It is found that jets with smooth holes, regardless of their types, do not provide fuel combustion. It is found that the transition to a new low-temperature convective method led to a reduction in fuel consumption during the drying process, which, in turn, made it possible to save 300 thousand rubles during the harvesting period on the experimental farm in 2022.

Study on Internal Flow Characteristics and Abrasive Wear of Pelton Turbine in Sand Laden Water

When a Pelton turbine operates in sand laden water, the abrasive wear of its overflow components by high-speed jets is serious. Based on the VOF (volume of fluid) multiphase flow model, the SST (shear stress transfer) k-ω turbulence model, the particle motion Lagrangian model, the generic wear model, and the SIMPLEC (Semi-Implicit Method for Pressure Linked Equations Consistent) algorithm, the liquid–air–solid three-phase flow in the key overflow components of a Pelton turbine were simulated, the abrasive wear was predicted, and the internal sand-water flow characteristics and the abrasive wear of the overflow components were analyzed. The results show that the trailing edge at the root of the runner bucket, the leading face of the bucket near the root, the notch, and the splitter are severely worn. The abrasive wear of the splitter and the notch is more severe than that of the leading face of the bucket. The wear rate from the splitter to the trailing edge increases first and then decreases. The wear pattern of the needle tip is mainly “dotted”, while that of the nozzle opening is “flaky”, and the abrasive wear of the nozzle opening is more severe than that of the needle. The predicted results are consistent with the actual conditions at the site of the power station. This study provides a technical method for the prediction of abrasive wear of the Pelton turbine and a technical basis for the operation and maintenance of the power station.

Influences of a variable nozzle turbocharger on the combustion and emissions of a light-duty diesel engine at different altitudes

With social and economic developments, more light-duty vehicles are operating at high altitudes, but the reduced intake air flow in plateau areas, leads to poorer engine combustion and greater emissions. An effective means of improving plateau adaptability are light-duty diesel engines employing variable nozzle turbochargers (VNTs), but the research to date on how VNTs influence the combustion and emissions of diesel engines at high altitudes has lacked both depth and a systematic approach. Therefore, in the present research, experiments were conducted to investigate the influences of a VNT on the combustion and emissions of a light-duty diesel engine at different altitudes (0 m, 1000 m, and 2000 m) by using a plateau-environment simulation device. Also, the influences of altitude and VNT nozzle opening on the in-cylinder working process and pollutant generation were studied by means of three-dimensional numerical simulations. The results show that the VNT had almost the same ability to enhance the intake air flow at different altitudes within the same range of VNT nozzle opening, and the effect of increasing altitude on diesel engine performance was similar to that of increasing VNT nozzle opening. With increasing altitude or VNT nozzle opening, the spray penetration length increased, the in-cylinder equivalence-ratio distribution became less even, the start of combustion was delayed slightly, the combustion duration was extended, and the in-cylinder mean temperature increased. With increasing altitude or VNT nozzle opening, the emission of NOx decreased gradually, while those of CO, HC, and soot increased. Compared with the case at sea level, the influence of VNT nozzle opening on CO, HC, and soot emissions was more significant in plateau areas.