Initial Jet Velocity Research Articles

Research and application on modeling and landing point prediction technology for water jet trajectory of fire trucks under large-scale scenarios

To let water jets land at the fire, pitch angle of the fire monitor has to be adjusted manually with successive rounds, which seriously affects the efficiency of fire extinguishing. To improve the efficiency, this paper proposes a technology for water jet trajectory modeling and landing point prediction to help with extinguishing automatically. Considering fragmentation and atomization of water jets, trajectories are analyzed and the predicted trajectory is closer to the real situation. Secondly, a compensation method for the prediction is proposed to further reduce the deviation between the predicted and the actual landing point, taking into account the combined effects of high altitude, initial jet velocity, and wind. On this basis, considering the difficulty of directly solving the analytical solution to the target initial pitch angle of the jets, a searching method is also proposed, which greatly improves the solving efficiency. Finally, through practical experiments and verification, the proposed model takes an average time of 0.00292 s, which is far less compared with other methods. The prediction error is improved by at least 45.3%, and the average deviation is less than 2 m.

Simulation of flow field based on constrained fluid for electrolyte jet control

In previous studies, jets were controlled by adjusting parameters such as velocity, pressure, size and shape of nozzle, and temperature. In this study, a new method of controlling electrolyte jets was proposed by introducing a constrained fluid. To analyze the effects of the constrained fluid on the jet flow field, the initial jet velocity and velocity ratio of the flow field were examined. Simulation results showed that the proposed method can avoid stray deposition caused when the electrolyte is spread on the substrate surface. The electrolyte jet could be controlled by the constrained fluid, indicating the characteristic of cyclical fluctuation. The initial jet velocity and velocity ratio had different impacts on the flow field; the former mainly affected the velocity and pressure distribution. The relationship between the velocity of flow field and initial jet velocity was observed to be linear. However, the relationship between pressure of the flow field and initial jet velocity was quadratic. The velocity ratio had a significant impact on the state of electrolyte jet. At low initial jet velocities, the electrolyte jet was not continuous at different velocity ratios. When the initial jet velocity increased, cyclical fluctuations in the electrolyte jet weakened under high velocity ratios. The electrolyte jet diameter also decreased linearly as the velocity ratio increased. The velocity and pressure of the flow field were quadratically related to the velocity ratio. This indicates that the constrained fluid had a considerable impact on the flow field and state of the electrolyte jet. Moreover, the electrolyte jet could be controlled effectively by adjusting the initial jet velocity and velocity ratio to obtain a stable and small electrolyte jet diameter.

Jet-assisted membrane filtration and design application: A model for fouling removal area estimation

Membrane fouling remains a significant challenge in desalination and other membrane-based filtration processes. This study presents a novel force-balance model to accurately estimate the de-fouling area in jet-assisted filtration for in-situ fouling control. The model includes various design parameters, such as initial jet velocity, nozzle diameter, impinging angle, membrane pore size, membrane resistance, and permeate flux. The validation showed a strong correlation between theoretical predictions and experimental observations, with an R2 value of 0.97, indicating high predictive accuracy. Additionally, an empirical formula and design automation tools were developed to facilitate the configuration of jet filtration modules, enabling practical application of the findings. As a demonstration, the arrangement of multiple jets in a hollow fiber membrane module was optimized using the model, significantly improving microalgae filtration performance. The optimized jet configuration enhanced permeate flux by 236 % and reduced the specific energy consumption by 67 % compared to conventional setups. This research offers a framework for extending the application of jet-based fouling mitigation and cleaning in various membrane filtration systems, providing substantial improvements in efficiency and operational sustainability.

Experimental study on forced ventilation in dead-end mine working with various setbacks of the ventilation pipeline from the working face

The study of airflow patterns at the ends of dead-end mine workings is crucial for optimizing underground mining ventilation systems. Understanding these patterns forms the basis for designing and implementing effective ventilation strategies.Previous studies have shed light on the behavior of the main vortex and the formation of stagnant zones in such environments, but these insights remain fragmented and call for a more systematic exploration to integrate them into a comprehensive theory.This paper presents the results of a thorough field investigation into the forced ventilation behavior in a dead-end mine working with a significant cross-sectional area (29.2 m2). We evaluated the impact of varying the setback distance of the ventilation duct’s end from the working face at intervals of 10, 15, 17, 19, and 21 m. The experimental design included precise measurements of turbulent airflow velocities at 25 carefully chosen points (in a 5x5 grid) for each setback distance, covering the area from the working face to beyond the end of the ventilation duct. This included additional measurements taken 1 meter and 10 meters past the termination of the ventilation duct, moving towards the entrance of the working area.The fieldwork was carried out in a typical dead-end stope at the Kupol gold-silver mine in the Chukotka Autonomous District, created by drilling and blasting.The volume of fresh air delivered to the working was maintained at a consistent rate of 17.4 m3/s across all scenarios, aligning with the mine’s standard air flow rate derived from the ventilation requirement for exhaust gases emitted by internal combustion engines of Load-Haul-Dump (LHD) machinery. With the duct’s terminal cross-sectional area at 0.8 m², this resulted in an inflow velocity averaging 21.75 m/s.Additionally, we included insights from three-dimensional numerical simulations performed in ANSYS Fluent, focusing on steady-state air movement and developed turbulence within the dead-end space. A comparative review of both empirical and modeled data shows that the ventilation jet, for all tested setback distances up to 21 m, successfully delivered air to the working face, where it then dispersed and initiated reverse flow patterns.These experiments led to the formulation of a linear relationship between the maximum relative velocity (compared to the initial jet velocity) at a distance of 1 m from the working face and a key geometric factor of the ventilation setup. This factor is the ratio of the duct’s setback distance to a characteristic dimension of the cross-sectional area, calculated as the square root of the cross-sectional area.

Primary breakup model development for trajectory prediction of liquid jets in subsonic crossflow

A comprehensive theoretical model for the primary breakup of liquid jets in subsonic crossflow was developed. The model theoretically analyzed the jet deformation process, mass stripping process, and the influence of several critical forces and consequently provided highly accurate predictions of the jet trajectory. Deformation of the liquid jet cross section was considered as a two-stage process based on the physical characteristics, including the spring-mass analogy deformation and the mass stripping induced deformation. The mass stripping process was modeled as an exponential function of time based on experimental findings for liquid jets and droplets. Balance of critical forces acting on the jet were analyzed, both along the gas and jet flow directions, which included aerodynamic drag, viscous force, surface tension, and gravitation. The model provided precise prediction to the jet trajectory against experimental data without any initial jet velocity assumption across a wide range of gaseous Weber numbers and gas to liquid momentum ratios. In addition, quantitative effects of viscous force, surface tension force, and aerodynamic drag on jet trajectory were fully investigated based on the new model, which provided more insight into jet breakup characteristics and the effects of fuel properties on jet trajectory and deformation. Furthermore, the three-dimensional structure of the jet was reconstructed through the present model, which matched well against numerical results. Importantly, the current mathematical primary breakup model could be integrated with Lagrangian methods, obtaining more detailed vortex structures and accurate droplet dispersion with reduced computational time.

Fugitive Emission Characteristics of Fume and Dust from Short-Process Electric Furnace Tap Hole and Optimization of Dust Hood

Due to the advantages of a short cycle, low investment and low energy consumption per ton of steel, short-process electric furnace steelmaking is about to welcome a golden period of rapid development in China. During the operation of the electric furnace, a large amount of smoke and dust is generated. Most studies focus on organized emissions, and the impact of unorganized emissions in workshops on the environment cannot be ignored. This paper evaluates the thermal environment in the electric furnace steelmaking workshop based on the analytic hierarchy process and obtains the influence weight of the fugitive emission location. The mass concentration of dust at each measuring point increased by 1.17 mg/m3 on average, and the concentration of unorganized emission dust near the outlet was 23.572 mg/m3. The numerical simulation calculation model is established by the CFD method, a fixed initial jet velocity is set, the initial velocity of the ladle soot plume is changed, and the inclination angle, arrangement height and dust removal air volume of the dust hood are respectively adjusted in different tapping periods. The impact of simulation on the efficiency of dust collection for different dust removal hood configurations was investigated, considering variations in inclination angle, arrangement height and dust removal airflow. The optimal structural parameters for the dust removal hood were determined to be an inclination angle of 60° and an arrangement height of 2.4 m, and an optimal dust removal airflow was determined to be 110,000 m3/h. This study provides a theoretical foundation for engineering practice.

Optimisation of initial velocity distribution of jets for entrainment and diffusion control using deep reinforcement learning

The control of the entrainment and diffusion of the heat and mass ejected along the jet flow requires the control of fluid motion. In the present study, optimal initial velocity distributions for suppressing and promoting jet entrainment and diffusion were identified using deep reinforcement learning under constant initial jet flow rate conditions. Two-dimensional jet flow simulations using OpenFOAM were combined with a deep Q-network as the learning algorithm. The spatial distribution of the initial jet (velocity and ejection angle) changed. The results show that to suppress the entrainment of the jet, an optimal initial velocity distribution shape in which the velocity in the centre is almost 0, with an inward velocity just outside of it, and a large outward velocity at the outer edge, is desirable. However, to promote entrainment, a shape with a large velocity in the centre portion and small velocity at the outer edge, with an overall inward angle, is desirable. To suppress the diffusion of the jet, an optimal initial velocity distribution shape with a large velocity in the centre portion, a small velocity at the outer edge, and an overall inward angle is desirable. Conversely, to promote diffusion, a shape with a large outward velocity at both the centre and outer edges is desirable. It is also indicated that, when the initial velocity distribution of the jet has a special shape, and the relationship between flow rate, centre velocity, and centre temperature that is normally observed in a jet flow may not hold. In other words, by changing the initial velocity distribution, the entrainment and diffusion of the jet can be separated and controlled, which is usually difficult to achieve using conventional engineering methods.

Theoretical analysis on electrohydrodynamic instability of a low viscous electrified jet

In present work, a dispersion equation describing electrohydrodynamic (EHD) instability of a low viscous electrified jet was derived, where the Naiver-Stokes equations combined with the electrodynamic and hydrodynamic boundary conditions are utilized. The effect of operating parameters containing electric potential, initial jet velocity and electrode spacing on stability of the electrified jet was systematically examined and extensively analyzed, as well as liquid properties including liquid viscosity and surface tension. The analysis indicate that the axisymmetric surface waves dominate the breakup instability of the electrified jet at low electric potential or low flowrate. As flowrate or electric potential increases, the influence of the non-axisymmetric surface waves is gradually enhanced. The electrode spacing and initial diameter of the jet also have extremely slight effect on the surface wave growth rate. The viscosity could stabilize the electrified jet and almost has no influence on the maximum wave number. With the surface tension increasing, the stability of the jet is usually enhanced. The analytical results agree well with the experimental observation in the varicose instability. Meanwhile, the discrepancy between the predicted and experimental data in the whipping instability indicates the influence of non-linear perturbations is indispensable.

Experimental investigation of various energy-absorbing layer materials and sodium alginate viscosities on the jet formation in laser-induced-forward-transfer (LIFT) bioprinting

Laser-induced-forward-transfer (LIFT) bioprinting technology has been viewed as a regenerative medicine technology because of its high printing quality and good cell viability. To stabilize the jet to achieve high-quality printing, an energy-absorbing layer (EAL) can be introduced. In this study, three materials (graphene, gelatin, and gold) were utilized as the EAL. The effect of each EAL on the jet generation process was investigated. Besides, the effect of graphene EAL thickness was addressed for various experimental conditions. The jet generation process using sodium alginate solutions with different concentrations (1 and 2 wt. %) was also discussed to investigate the effect of viscosity. The time sequence images of the formed jets utilizing three EALs showed that both graphene EAL and gelatin EAL can promote the formation of jet flow. For the gold EAL, no jet flow was observed. This study provides experimental verifications that the interaction between laser and EAL materials can result in different jets due to various dominant interaction mechanisms. For example, strong absorption in the infrared range for the graphene EAL, strong scattering loss for the gelatin EAL, and strong absorption in the ultraviolet range but weak absorption in the infrared for the gold EAL. We also observed the holes left on the EAL after the printing was completed. The thermal effect is dominant to create regular and round shape holes for the graphene EAL, but it changes to the mechanical effect for the gold EAL because of the existence of irregular and unorganized holes. In addition, we identified the existence of an input laser energy threshold value for a certain thickness graphene EAL. More laser energy is required to break down thicker graphene EALs, which will result in a higher initial jet velocity. Furthermore, we explored the effect of sodium alginate (SA) solution's viscosity on the generated jet. We found that a high-viscosity SA solution can result in a low initial jet velocity, a short jet, and small droplets on the receiving substrate. The findings from this study help determine the mechanisms of EAL–laser interaction with different EAL materials in the LIFT process. This work aims to facilitate the development of new EAL and bioink to achieve stable jet formation and high printing quality in future LIFT bioprinting.

Effect of fluidic obstacles on flame acceleration and DDT process in a hydrogen-air mixture

Using solid obstacles to accelerate the deflagration to detonation transition (DDT) process induces additional thrust loss, and fluidic obstacles can alleviate this problem to a certain extent. A detailed simulation is conducted to investigate the effects of multiple groups of fluidic obstacles on the flame acceleration and DDT process under different initial velocities and gas types. The results show that, initially, the propagation of reflected shock wave formed by jet impingement is opposite to the flame acceleration direction, thus increasing the initial jet velocity will hinder the flame acceleration. Later, the vortex structure and enhanced turbulence can promote flame acceleration. As the flame accelerates, the virtual blockage ratio of the fluidic obstacles decreases, and increasing initial jet velocity or using reactive jet gases both affect the virtual blockage ratio. Further, increasing initial jet velocity or using reactive jet gases can shorten the detonation initiation time and distance. Compared with solid obstacles, it is concluded that fluidic obstacles can achieve faster detonation initiation with a smaller blockage ratio. Overall, the detonation phenomena in this study are all triggered by hot spots formed by the interaction between reflected waves and distorted flame, but the formation of reflected waves varies.

Numerical investigation of the effect of reactive gas jets on the flame acceleration and DDT process

Jet obstacles can quickly induce the deflagration to detonation transition (DDT) process and reduce the thrust loss of an engine. However, there are few studies on the use of combustible premixed gases as the reactive jet obstacle. Based on the OpenFOAM platform, a detailed numerical investigation of the flame acceleration and DDT process is carried out with different initial jet velocities and the number of jet obstacles. The results show that, although the stronger flame generated by the reactive jet obstacles will reduce the virtual blockage ratio to a greater extent, the turbulence and combustion heat release effect generated by them still significantly promote the flame acceleration. In terms of flame acceleration, initially, increasing the initial jet velocity has no obvious effect on the flame acceleration. Later, turbulence and combustion heat release begin to dominate the flame acceleration and significantly promote the flame acceleration. Since the jets in this study adopt the same combustible premixed gases, increasing the number of reactive jet obstacles downstream does not improve the upstream flame acceleration. In DDT, increasing the initial velocity of the reactive jet can improve the detonation initiation, but the effect of the obstacle number on DDT is greatly affected by the initial jet velocity. Specifically, at a low initial jet velocity, more jet obstacles can significantly promote the detonation initiation, while at a high initial jet velocity, the enhanced turbulence caused by the jet is the dominant factor for the flame acceleration. Therefore, compared with the number of jet obstacles, the detonation initiation process of the premixed gases is more sensitive to the change in the initial jet velocity.

Study on Dynamic Performance and Induced Breakdown of the Plasma-Triggered-Based Protective Gas Gap Switch

The plasma-triggered-based protective gas switch (PTGS) has obvious advantages in the control switch application of fast energy dissipation device used in the hybrid dc transmission projects. However, the high-pressure environment critically limits the plasma jet ability, easily leading to the trigger failure. Therefore, this article establishes a plasma-jet-triggered experimental platform to study the dynamic performance and induced breakdown laws of PTGS. It is shown that the evolution of plasma jet is divided into three stages: plasma jet of high-pressure, saturated stability, and dissipation. The induced breakdown mainly occurs in the high-pressure jet and saturated stability stage. The initial plasma jet velocity increases, as the energy storage capacitance and the charging voltage increase, making it faster to reach the jet length for induced breakdown, resulting in a significant reduction in switch-on time and improving the PTGS trigger stability. The increase in trigger gas pressure inhibits the plasma jet ability, but improves the electrical strength of PTGS. In order to achieve induce breakdown of PTGS, the plasma jet must reach the critical jet length. SF6 gas improves the insulation strength of PTGS and prevents the formation of plasma jet. To achieve stable trigger conduction, the trigger energy of PTGS must be increased. The findings can be used to develop theoretical guidance for improving the working performance of the high-voltage and large-capacity protective gas gap switches (GGSs).

Study on Triggering Characteristics and Induced Breakdown Rules of SF₆ Gap Switch Plasma Jets at Extremely Low Working Voltage

The SF₆ gap switch has obvious advantages in the flexible control very fast switch of the controllable arrester used in hybrid UHVDC system. However, the plasma jet ability in SF₆ atmosphere at high pressure is greatly restricted, which is easy to cause trigger failure. The triggering characteristics and induced breakdown mechanism are still unclear during the plasma jet-triggered process of the SF₆ gap switch at extremely low working voltage. In this study, a plasma jet-induced breakdown research platform based on two-stage continuous surface-triggered gas gap switch (GGS) was established to investigate time-space distribution evolution characteristics, the critical triggering conditions parameters, and working voltage functioning rules of the SF₆ gap. The jet plasma has a high-brightness-like conical shape, and its initial jet velocity can reach more than 2 km/s. Increasing capacitance value and charging voltage of the secondary chamber in SF₆ gap switch trigger cavity, its creeping arc current is increased, and the time delay and dispersion will be reduced. Moreover, the geometric characteristics (including jet area, jet radial and axial length, and jet velocity) and electrical parameters of the jet plasma increase gradually. Increasing the working voltage of main gap in SF₆ gap switch, the plasma jet velocity lift phenomenon appears at induced breakdown end of SF₆ gap switch. With the continuous increase of the working voltage, the lift effect is more significant. The purpose of this study is to solve the key problem of plasma-induced breakdown failure of the SF₆ gap switch, which will guide the design of fast self-recovery energy discharge protection switches for hybrid UHVDC transmission systems.

Numerical study of hydraulic fragmentation of melt jet in coolant: Breakup length and melt-coolant contact area

Hydraulic fragmentation of melt jet is an important phenomenon during fuel-coolant interaction (FCI) of nuclear reactor severe accident. If the melt jet has not broken up completely before contacting the lower head, it may ablate the vessel wall and a compact debris bed may form. The jet breakup length and melt-coolant contact area are important parameters describing melt fragmentation. In this study, therefore, a numerical model for analyzing melt jet hydraulic fragmentation was developed and validated against the experiment. Through the analysis of UO2 melt jet fragmentation in coolant under various conditions, the relationship between the morphological structures and axial velocities of melt jet was clarified, and an accurate criterion for judging jet breakup length was proposed. The effects of initial melt jet velocity and diameter on the dimensionless breakup length were investigated, and an empirical equation for calculating breakup length was established with a maximum deviation about 10%. The dimensionless contact area of melt and coolant increased as the melt was injected into the coolant, but it finally reached a stable value for each case. It increased as the increase of initial injecting velocity, but was not affected by the initial melt jet diameter. The empirical equation for calculating the dimensionless contact area was established as well, and the prediction deviation was less than 10%.

Computational study on effects of jet fans to traffic force in highway tunnel

Traffic force induced by the piston effect of moving vehicles is a major driving force to the airflow in road tunnels. To ensure an adequate flow rate in the tunnel, an accurate estimation to the traffic force is necessary. This work investigates the influence of jet fans to the traffic force of a large vehicle in a long highway tunnel. A numerical model of airflow in the tunnel is established based on RANS (Reynolds Averaged Narvier-Stokes) equations, and dynamic mesh method is utilized to simulate the moving vehicle. Results show that, traffic force is significantly amplified when the vehicle passes the jet fans, which can be explained by the non-uniform velocity profile under the entrainment of high-speed jets. A parametric analysis is conducted to the effects of initial jet velocity, vehicle speed and ventilating velocity of tunnel. Finally, an improved correlation is proposed to evaluate the drag coefficient and traffic force of the vehicle within the affecting range of air jets.

Physical and numerical assessments of the penetration behavior of coplanar linear shape charges

In this study, we aimed to demolish irregular constructions that are usually composed of convex, concave, and straight structures based on the shaped charge jet. Accordingly, the penetration behaviour of convergent, divergent, and straight linear shaped charges (LSCs) have been detected with numerical and physical methods. For comparison purposes, numerical models for all three types of LSCs with identical cross-sections have been established to investigate the impacts of structural features. It is found that the shaped charge structure not only determines the kinematic consumption during the penetration process but also influences the initial value of the jet velocity. Additionally, because of the interactions between the previous and subsequent jets, the jet velocity of the convergent LSC shows an obvious undulation during the penetration process. Furthermore, quantitative analyses of the kinematic consumption and initial velocity differences for three types of LSCs are conducted with physical models. A kinematic consumption difference is revealed, and the mass of the charge that determines the initial jet velocity as a function of the geometric parameters in three types of LSCs is deduced. Finally, we combined the numerical and physical models and conducted integral analyses to assess the penetration behaviours of the three LSC types.

Breakup characteristics of high speed liquid jets from a single-hole injector

In this study, spray characteristics from a single-hole gasoline direct injection injector with nozzle diameters of 0.14 mm and 0.2 mm were investigated. High-speed macroscopic and microscopic imaging techniques were applied to record the overall spray structure and the initial fuel spray behavior. The injection pressure ranged from 50 bar to 350 bar, and the ambient pressure was kept constant at 1 bar. Several semi-empirical models for predicting spray penetration at non-evaporating conditions were investigated, including models by Dent, Hiroyasu and Arai, and Naber and Siebers. Results showed that the Naber and Siebers equation demonstrated the best match with the experimental data. Both the initial and global spray penetration were well predicted. The spray penetration can be divided into two regions based on the relationship between spray penetration and injection time, namely the regions before and after breakup, and the transitional point was defined as the breakup point. Higher fuel pressures resulted in shorter breakup time and length for the injector with the smaller nozzle diameter, and the injector with larger nozzle diameter produced shorter breakup time and longer breakup length. A linear relationship was identified between the initial spray penetration and injection time at all fuel pressures, which indicates the initial spray tip velocity can be treated as constant at each fuel pressure. The ratio between the slope of experimental initial spray penetration and average flow velocity (based on static flow rate measurements) was around 0.9 at all fuel pressures for the injector with 0.14 mm nozzle diameter. Consequently, the average flow velocity obtained based on the static flow rate at each fuel pressure can be used to accurately predict the initial jet velocity.

Positive Phase Pressure Function and Pressure Attenuation Characteristic of a Liquid Carbon Dioxide Blasting System

As environmental requirements become more stringent, the liquid carbon dioxide blasting system is one of the non-explosive blasting technologies that, with low tensile stress energy, will replace the chemical explosive blasting technology, and the impact pressure characteristic of high-pressure fluid is a crucial factor in the process of rock breaking. To further investigate the impact and pressure attenuation characteristics of high-pressure fluid during the phase transition of liquid carbon dioxide blasting system, the pressure curves of high-pressure fluid in liquid carbon dioxide blasting systems at different distances were measured in the laboratory. Based on the mechanism analysis of phase transition kinetics, the initial jet velocity of the four experiments was calculated, and the rationality of results was verified by the Bernoulli equation. The general expression of the positive phase pressure–time function was proposed, and the idealized impact pressure curve can be divided into five stages. The impact pressure field of the liquid carbon dioxide blasting system can be divided into three areas at different distances: the explosive jet impact zone, the jet edge zone and the shock wave action zone, and the pressure–contrast distance fitting equation of the liquid carbon dioxide blasting system were obtained.

Turbulence Driven by Stellar Jets, the Possibility and the Efficiency

Abstract We investigate the feedback of the stellar jets on the surrounding interstellar gas based on 2D and 3D simulations applying HD and MHD modules of the PLUTO 4.2 code. The main question we address is whether the stellar jet can be considered as a turbulence driver into the interstellar gas. In addition, we investigate the most effective circumstances in which the driven turbulence is larger and can survive for a longer timescale in the ambient gas. We present a case study of different parameter runs including the jet Mach number, the initial jet velocity field, the background magnetic field geometries and the interacting jets. We also study the environmental effects on the jet-gas interaction by considering the non-homogeneous surrounding gas containing the clumps in the model setup. Among different setups, we find (1) a higher jet Mach number, (2) a rotating jet, (3) a jet propagating in a magnetized environment, (4) a jet propagating in a non-homogeneous environment, and (5) the interacting jets produce more fluctuations and random motions in the entrained gas, which can survive for a longer timescale. In addition, we perform the 3D simulations of jet-ambient gas interaction and we find that the amount of (subsonic–supersonic) fluctuation increases compared to the axisymmetric run, and the entrained gas gains higher velocities in a 3D run. In total, we confirm the previous finding that the stellar jets can transfer the turbulence on neighboring regions and are not sufficient drivers of the large-scale supersonic turbulence in molecular clouds.

ТЕОРИЯ РАСПЫЛИВАНИЯ ЖИДКОСТИ ФОРСУНКАМИ

The main characteristics are considered and calculations of the main indicators of nozzle devices are given. Laboratory tests of nozzles of various configurations were carried out to determine the working width of the spot at different distances to the irrigated surface and the angle of the spray pattern, and dependencies were established to determine their effective mode of operation. As a result of testing nozzles with different spray patterns when determining the impact force of the jet, it was found that as the spray angle increases, the value of the impact force of the jet F decreases. This is due to the fact, that with an increase in the initial jet velocity, the torch length reaches a maximum, not only does the kinetic energy increase, but the sizes (diameters) of the sprayed medium drops, which leads to a decrease in droplet mass and an increase in the aerodynamic resistance of the torch jet particles. A bench for determining the impact force of a jet of various nozzles was developed and test results were obtained. During operation, due to the erosive wear of the jet holes of the nozzles, its diameter increases, as a result, the working atomization pressure drops, and the number and size of large particles increase. Therefore, periodically it is necessary to check the diameter of the nozzle holes and not to use nozzles, that have a hole diameter greater than the initial one by 10 or more percent. In the study of nozzles, the dependences of nozzles’ characteristics on the initial parameters of the outflow of the liquid jet to the dispersity and shape of the torch were established. The values of irrigation spot width are established depending on the angle of the torch and the distance from the nozzle to the irrigated surface. The magnitude of the impact force of the jet, which occurs at the point of contact of the fluid jet with the irrigated surface, is determined.