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Articoli di riviste sul tema "Nozzle-exit conditions"

Autore: Grafiati

Pubblicato: 7 luglio 2024

Ultima modifica: 31 luglio 2025

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1

Kozlov, Viktor, Genrich Grek, Oleg Korobeinichev, Yuriy Litvinenko, and Andrey Shmakov. "Influence Of Initial Conditions At The Micro Nozzle Exit On Hydrogen Diffusion Combustion." Siberian Journal of Physics 11, no. 3 (2016): 34–45. http://dx.doi.org/10.54362/1818-7919-2016-11-3-34-45.

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The purpose of the given work will consist in an experimental study of influence of initial conditions at the micro nozzle exit on hydrogen diffusion combustion. It is shown, that the mean velocity profile and presence/absence of a heatcapacious material at the nozzle exit play an essential role on a flame structure and process of a round hydrogen microjet combustion. Velocity ranges of existence of a round hydrogen microjet diffusion combustion, flame separation and «bottleneck flame» region for a case of a top – hat mean velocity profile at the nozzle and two cases of a parabolic mean veloci

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2

Lepicovsky, J. "An Experimental Investigation of Nozzle-Exit Boundary Layers of Highly Heated Free Jets." Journal of Turbomachinery 114, no. 2 (1992): 469–75. http://dx.doi.org/10.1115/1.2929167.

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An experimental investigation of the effects of nozzle operating conditions on the development of nozzle-exit boundary layers of highly heated air free jets is reported in this paper. The total pressure measurements in the nozzle-exit boundary layer were obtained at a range of jet Mach numbers from 0.1 to 0.97 and jet total temperatures up to 900 K. The analysis of results shows that the nozzle-exit laminar boundary-layer development depends only on the nozzle-exit Reynolds number. For the nozzle-exit turbulent boundary layer, however, it appears that the effects of the jet total temperature o

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3

Chen, Hongjie, Bingxu Chen, Zhizhou Xu, Jing Ge, Honghua Chen, and Zhaoqi Zhong. "A Thermodynamic Model for Performance Prediction of an Ejector with an Adjustable Nozzle Exit Position." Processes 13, no. 3 (2025): 879. https://doi.org/10.3390/pr13030879.

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Improving the efficiency of ejectors during off-design operations can be effectively achieved through the automatic adjustment of the nozzle exit position (NXP). A thermodynamic model for predicting the performance of an ejector with an adjustable nozzle position is proposed and validated. The key factors influencing the optimal nozzle exit position under variable operating conditions are analyzed using the model. The dimensionless optimal nozzle exit position (DONXP) of the ejector is fitted as a function of these key factors, and a nozzle exit position adjustment scheme for variable operatin

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4

Fontaine, Ryan A., Gregory S. Elliott, Joanna M. Austin, and Jonathan B. Freund. "Very near-nozzle shear-layer turbulence and jet noise." Journal of Fluid Mechanics 770 (March 27, 2015): 27–51. http://dx.doi.org/10.1017/jfm.2015.119.

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One of the principal challenges in the prediction and design of low-noise nozzles is accounting for the near-nozzle turbulent mixing layers at the high Reynolds numbers of engineering conditions. Even large-eddy simulation is a challenge because the locally largest scales are so small relative to the nozzle diameter. Model-scale experiments likewise typically have relatively thick near-nozzle shear layers, which potentially hampers their applicability to high-Reynolds-number design. To quantify the sensitivity of the far-field sound to nozzle turbulent-shear-layer conditions, a family of diame

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5

Wang, P. C., and J. J. McGuirk. "Validation of a large eddy simulation methodology for accelerated nozzle flows." Aeronautical Journal 124, no. 1277 (2020): 1070–98. http://dx.doi.org/10.1017/aer.2020.12.

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ABSTRACTPrediction of aeroengine exhaust plume near-field development requires knowledge of velocity and turbulence distributions at nozzle exit. The high Reynolds number nozzle inlet boundary layers of engineering practice are fully turbulent, but acceleration can induce re-laminarisation. Thus, to reproduce nozzle exit conditions accurately, large eddy simulation (LES) for plume prediction must be capable of capturing re-laminarisation and any subsequent boundary layer recovery. Validation is essential to establish a credible LES methodology, but previous studies have suffered from lack of n

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6

Mokni, Amèni, Jamel Kechiche, Hatem Mhiri, Georges Le Palec, and Philippe Bournot. "Numerical Study of the Inlet Conditions Influence on Laminar Plane Wall Jets." Defect and Diffusion Forum 273-276 (February 2008): 406–12. http://dx.doi.org/10.4028/www.scientific.net/ddf.273-276.406.

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In this paper, we present a numerical investigation of a laminar isothermal plane two dimensional wall jets. Special attention has been paid to the effect of the inlet conditions at the nozzle exit on the flow thermal characteristics in forced convection regime. Two velocities profiles at the nozzle exit are used: uniform profile and parabolic profile. The system of equations governing the studied configuration is solved with a finite difference scheme and an implicit scheme, for numerical stability we use a staggered non uniform grid. The obtained results show, first, that the inlet condition

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7

Huh, Kang Y., Eunju Lee, and Jaye Koo. "DIESEL SPRAY ATOMIZATION MODEL CONSIDERING NOZZLE EXIT TURBULENCE CONDITIONS." Atomization and Sprays 8, no. 4 (1998): 453–69. http://dx.doi.org/10.1615/atomizspr.v8.i4.60.

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8

Liu, Fuhai, Songchao Lu, Sibao Zeng, Rong Zhu, Guangsheng Wei, and Kai Dong. "Flow Field of Supersonic Oxygen Jet Generated by Various Wear Lengths at the Laval Nozzle Exit." Coatings 14, no. 11 (2024): 1444. http://dx.doi.org/10.3390/coatings14111444.

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As a main apparatus, the oxygen lance is used to deliver the oxygen element and transfer kinetic energy into the molten bath in the steelmaking process. However, the Laval nozzle exit would be gradually worn out during the service life, which suppresses the performance of the oxygen lance. This paper investigated three different wear length (Lw) conditions at the exit of the Laval nozzle through numerical simulations and high-temperature experiments with various oxygen flow rates. The result showed that the entrainment of the ambient gas was the key factor of the wear phenomenon for the Laval

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9

Liu, Meng, and Yufeng Duan. "Predicting the Liquid Film Thickness and Droplet–Gas Flow in Effervescent Atomization: Influence of Operating Conditions and Fluid Viscosity." International Journal of Chemical Reactor Engineering 11, no. 1 (2013): 393–405. http://dx.doi.org/10.1515/ijcre-2013-0073.

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Abstract The droplet–gas flow in effervescent atomization was simulated using a comprehensive numerical model. Liquid film thicknesses in the nozzle exit orifice and droplet size distribution at the downstream of spray were calculated. The thickness of liquid film in the nozzle exit orifice increased and approached the droplet size in the primary atomization, as the air–liquid ratio increased. The primary breakup model can accurately predict the Sauter mean diameter in the primary atomization when gas–liquid two-phase flow belongs to the annular flow in the nozzle exit orifice. The viscosity o

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10

Kim1, H.-D., J.-H. Kim, K.-A. Park, T. Setoguchi, and S. Matsuo. "Study of the effects of unsteady downstream conditions on the gas flow through a critical nozzle." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 218, no. 10 (2004): 1163–73. http://dx.doi.org/10.1243/0954406042369053.

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The present study addresses a computational result of unsteady gas flow through a critical nozzle. The axisymmetric unsteady compressible Navier-Stokes equations are solved using a finite volume method that makes use of the second-order upwind scheme for spatial derivatives and the multi-stage Runge-Kutta integral scheme for time derivatives. The steady solutions of the governing equation system are validated with the previous experimental data to ensure that the present computational method is valid to predict the critical nozzle flows. In order to simulate the effects of back-pressure fluctu

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11

Menon, Pranav. "Investigation of Variation in the Performance of an Electro Thermal Thruster with Aerospike Nozzle." Advanced Engineering Forum 16 (April 2016): 91–103. http://dx.doi.org/10.4028/www.scientific.net/aef.16.91.

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One of the most recently developed modes of propulsion is electric propulsion. The commonly used chemical propulsion systems have the advantage of a high Specific Impulse as compared to that of ion propulsion systems. However, owing to the efficacy of ion propulsion systems, it is considered the future of space exploration.Electro thermal thrusters produce thrust by using electrical fields to force hot plasma out of the nozzle with certain exit velocity. The plasma’s exit velocity and the system’s thrust capacity, as of now, are insufficient for space travel to be conducted within a reasonable

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12

Laitón, Sergio Nicolas Pachón, João Felipe de Araujo Martos, Israel da Silveira Rego, George Santos Marinho, and Paulo Gilberto de Paula Toro. "Experimental Study of Single Expansion Ramp Nozzle Performance Using Pitot Pressure and Static Pressure Measurements." International Journal of Aerospace Engineering 2019 (February 27, 2019): 1–11. http://dx.doi.org/10.1155/2019/7478129.

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In order to overcome the drag at hypersonic speed, hypersonic flight vehicles require a high level of integration between the airframe and the propulsion system. Propulsion system based on scramjet engine needs a close interaction between its aerodynamics and stability. Hypersonic vehicle nozzles which are responsible for generating most of the thrust generally are fused with the vehicle afterbody influencing the thrust efficiency and vehicle stability. Single expansion ramp nozzles (SERN) produce enough thrust necessary to hypersonic flight and are the subject of analysis of this work. Flow e

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13

Mitruka, Jatin, Pranav Kumar Singh, and E. Rathakrishnan. "Exit Geometry Effect on Jet Mixing." Applied Mechanics and Materials 598 (July 2014): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.598.151.

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An elliptical nozzle of 3:1 aspect ratio (AR) issuing a Mach 1.5 jet has been used to investigate its mixing promoting efficiency under over-expanded and under-expanded conditions at the nozzle exit. Azimuthal asymmetry of the elliptical shape is interpreted as a benefit to the mixing process, which is significantly enhanced in comparison to an equivalent circular jet under identical conditions. The elliptical jet decays faster than its circular counterpart throughout the jet field. It is found that continuous variation in the size of the mixing promoting vortices shed from the nozzle exit, as

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14

Jeon, Yongseok, Hoon Kim, Jae Hwan Ahn, and Sanghoon Kim. "Effects of Nozzle Exit Position on Condenser Outlet Split Ejector-Based R600a Household Refrigeration Cycle." Energies 13, no. 19 (2020): 5160. http://dx.doi.org/10.3390/en13195160.

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The objective of this study is to investigate the performance characteristics of a small-sized R600a household refrigeration system that adopts a condenser outlet split (COS) ejector cycle under various operating and ejector geometry conditions. The coefficient of performance and pressure lifting ratio of the COS ejector cycle were analyzed and measured by varying the entrainment ratio, compressor speed, and nozzle exit position. The optimum nozzle exit position in the COS ejector cycle adopted to achieve the maximum cycle performance was proposed as a function of the compressor speed and entr

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15

Vinod, G., S. Renjith, and V. Thaddeus Basker. "Thermo Structural Analysis of Carbon-Carbon Nozzle Exit Cone for Rocket Cryo Engines." Applied Mechanics and Materials 877 (February 2018): 320–26. http://dx.doi.org/10.4028/www.scientific.net/amm.877.320.

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Launch and space vehicle structures are required to be extremely weight efficient. The need to achieve the performance required for the engine in the upper stage of a launch vehicle, increase the payload capacity drives rocket engine manufacturers to seek higher thrust level, specific impulse and thrust to weight ratio. The use of high temperature C-C composite materials is an efficient way to reach these objectives by allowing use of high expansion ratio. Nozzle extensions benefiting of the outstanding thermal, mechanical and fatigue resistance of these materials to decrease mass and featurin

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16

Choi, Myeung Hwan, Yoojin Oh, and Sungwoo Park. "Investigation of Spray Characteristics for Detonability: A Study on Liquid Fuel Injector and Nozzle Design." Aerospace 11, no. 6 (2024): 421. http://dx.doi.org/10.3390/aerospace11060421.

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Detonation engines are gaining prominence as next-generation propulsion systems that can significantly enhance the efficiency of existing engines. This study focuses on developing an injector utilizing liquid fuel and a gas oxidizer for application in detonation engines. In order to better understand the spray characteristics suitable for the pulse detonation engine (PDE) system, an injector was fabricated by varying the Venturi nozzle exit diameter ratio and the geometric features of the fuel injection hole. Analysis of high-speed camera images revealed that the Venturi nozzle exit diameter r

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17

V. Kozlov, Grigory, Genrich R. Grek, Aleksandr M. Sorokin, and Yuriy A. Litvinenko. "Influence of Initial Conditions at Nozzle Section on Flow Structure and Instability of Plane Jet." Siberian Journal of Physics 3, no. 3 (2008): 14–33. http://dx.doi.org/10.54362/1818-7919-2008-3-3-14-33.

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Experimental data concerning the influence of initial conditions at the nozzle exit on the structure and development characteristics of plane jet are reported. Features in the development of laminar and turbu-lent round jets emanating from variously elongated nozzles at identical Reynolds numbers are revealed. Smoke visualization pictures obtained for jets formed under different initial conditions (with different distributions of mean and pulsating flow velocities at the nozzle exit), influence of acoustic and interac-tion of streaky structures with vortex trail of laminar plane jet are discus

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18

Bruce Ralphin Rose, J., and J. Veni Grace. "Performance analysis of lobed nozzle ejectors for high altitude simulation of rocket engines." International Journal of Modeling, Simulation, and Scientific Computing 05, no. 04 (2014): 1450019. http://dx.doi.org/10.1142/s1793962314500196.

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Ejectors are used in high altitude testing of rocket engines to create vacuum for simulating the engine test in vacuum conditions. The performance of an ejector plays a vital role in creating vacuum at the exit of the engine nozzle and the nozzle design exit pressure at the time of ignition. Consequently, the performance of ejectors has to be improved to reduce the consumption of active fluid. In this investigation, the performance of an ejector has been improved by changing the exit shear plane of the nozzle. Conventionally, conical nozzles are used for creating the required momentum. Lobes o

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19

Anil Hemanth, Varada, and U. S. Jyothi. "CFD Analysis of a Solid Propellant Retro Rocket Motor using Ansys Fluent." E3S Web of Conferences 184 (2020): 01054. http://dx.doi.org/10.1051/e3sconf/202018401054.

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A Solid propellant Retro Rocket Motor with a C-D Nozzle is analyzed using Ansys Fluent 17.1 .Steady State analysis of a retro rocket motor has been done for Viscous models like Inviscid and k-ɛ (Realizable) with air and gas as working fluids. The dimensions and the boundary conditions of the nozzle are kept consistent for both the viscous models to compare the exit parameters to theoretical values obtained by using one dimensional equations. The results obtained shows that the exit temperature of the nozzle in Inviscid viscous model is higher than theoretical value by 2.2% and for k-ɛ viscous

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20

Wen, Kui, Min Liu, Kesong Zhou, et al. "The Influence of Anode Inner Contour on Atmospheric DC Plasma Spraying Process." Advances in Materials Science and Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/2084363.

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In thermal plasma spraying process, anode nozzle is one of the most important components of plasma torch. Its inner contour controls the characteristics of plasma arc/jet, determining the motion and heating behaviors of the in-flight particles and hence influencing the coating quality. In this study, the effects of anode inner contour, standard cylindrical nozzle, and cone-shaped Laval nozzle with conical shape diverging exit (CSL nozzle) on the arc voltage, net power, thermal efficiency, plasma jet characteristics, in-flight particle behaviors, and coating properties have been systematically

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21

Ghazwani, Hassan A., Afrasyab Khan, Pavel Alexanrovich Taranenko, et al. "Hydrodynamics of Direct Contact Condensation Process in Desuperheater." Fluids 7, no. 9 (2022): 313. http://dx.doi.org/10.3390/fluids7090313.

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Due to global environmental conditions, the focus of household heating has shifted from fossil fuels towards environmentally friendly and renewable energy sources. Desuperheaters have attracted attention as a domestic provision involving steam-induced direct contact condensation (DCC)to warm the water. The present study is an attempt to investigate the hydrodynamics in the desuperheater vessel experimentally, namely, when the pressurized pulsating steam is injected into the vessel, where the steam jet interacts co-currently with the slow-moving water. Flow visualization showed a circulation re

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22

Stevens, J., Y. Pan, and B. W. Webb. "Effect of Nozzle Configuration on Transport in the Stagnation Zone of Axisymmetric, Impinging Free-Surface Liquid Jets: Part 1—Turbulent Flow Structure." Journal of Heat Transfer 114, no. 4 (1992): 874–79. http://dx.doi.org/10.1115/1.2911895.

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This study characterized the mean and fluctuating parts of the radial component of the local velocity in the stagnation region of an impinging, free-surface liquid jet striking a smooth flat plate. Four different nozzle exit conditions were studied, including fully developed pipe flow, a contoured nozzle, and turbulence-damped and -undamped sharp-edged orifices. Liquid jet Reynolds numbers in the range 30,000 to 55,000 were investigated. Velocities were measured using laser-Doppler velocimetry. Mean velocities were found to vary nearly linearly with radial location, with the slope of the line

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23

Forster, M., and R. Steijl. "Design study of Coanda devices for transonic circulation control." Aeronautical Journal 121, no. 1243 (2017): 1368–91. http://dx.doi.org/10.1017/aer.2017.65.

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ABSTRACTCirculation control via blowing over Coanda surfaces at transonic freestream Mach numbers is investigated using numerical simulations. The performance and sensitivity of several circulation control devices applied to a supercritical aerofoil are assessed. Different Coanda devices were studied to assess the effect of Coanda radius-to-slot height ratio, nozzle shape and Coanda surfaces with a step. The range of operating conditions for which a supersonic Coanda jet remained attached at transonic freestream conditions were extended by increasing the radius of curvature at the slot exit fo

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24

BOGEY, C., and C. BAILLY. "Influence of nozzle-exit boundary-layer conditions on the flow and acoustic fields of initially laminar jets." Journal of Fluid Mechanics 663 (November 4, 2010): 507–38. http://dx.doi.org/10.1017/s0022112010003605.

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Round jets originating from a pipe nozzle are computed by large-eddy simulations (LES) to investigate the effects of the nozzle-exit conditions on the flow and sound fields of initially laminar jets. The jets are at Mach number 0.9 and Reynolds number 105, and exhibit exit boundary layers characterized by Blasius velocity profiles, maximum root-mean-square (r.m.s.) axial velocity fluctuations between 0.2 and 1.9% of the jet velocity, and momentum thicknesses varying from 0.003 to 0.023 times the jet radius. The far-field noise is determined from the LES data on a cylindrical surface by solving

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25

Li, Li, Zhi Hui Shi, and Tsutomu Saito. "A Survey of Fluidic Thrust Vectoring Nozzle by Numerical Analysis." Applied Mechanics and Materials 423-426 (September 2013): 1685–88. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1685.

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Numerical investigations are conducted to simulate the flow field of a 2D converging-diverging nozzle, for fluidic thrust vectoring. The numerical simulation of nozzle flow is carried out with Navier-Stokes equations model. Simulations are done with different primary and secondary jet conditions. The numerical results show that the smaller of the distance between secondary jet and exit, the larger is the thrust deflection angle. As the injection pressure ratio increases, the deflection angle increases followed on the premise of not far between secondary jet port and exit. The parameters play i

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26

Nanduri, Madhusarathi, David G. Taggart, and Thomas J. Kim. "A Study of Nozzle Wear in Abrasive Entrained Water Jetting Environment." Journal of Tribology 122, no. 2 (1999): 465–71. http://dx.doi.org/10.1115/1.555383.

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Parameters that influence nozzle wear in abrasive water jetting environment are identified and classified. Regular and accelerated wear test procedures are developed to study wear under actual and simulated conditions, respectively. In addition to exit diameter growth, nozzle weight loss and bore profiles are shown to better characterize and explain the wear phenomenon. The effect of nozzle geometry on wear is investigated by means of the developed test procedures and measures of wear. [S0742-4787(00)00202-2]

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27

Brès, Guillaume A., Peter Jordan, Vincent Jaunet, et al. "Importance of the nozzle-exit boundary-layer state in subsonic turbulent jets." Journal of Fluid Mechanics 851 (July 19, 2018): 83–124. http://dx.doi.org/10.1017/jfm.2018.476.

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To investigate the effects of the nozzle-exit conditions on jet flow and sound fields, large-eddy simulations of an isothermal Mach 0.9 jet issued from a convergent-straight nozzle are performed at a diameter-based Reynolds number of $1\times 10^{6}$. The simulations feature near-wall adaptive mesh refinement, synthetic turbulence and wall modelling inside the nozzle. This leads to fully turbulent nozzle-exit boundary layers and results in significant improvements for the flow field and sound predictions compared with those obtained from the typical approach based on laminar flow in the nozzle

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28

De Chant, L. J. "Subsonic Elector Nozzle Limiting Flow Conditions." Journal of Engineering for Gas Turbines and Power 125, no. 3 (2003): 851–54. http://dx.doi.org/10.1115/1.1581890.

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This paper describes an analytical method used to provide information concerning limiting flows for subsonic ejector nozzles. Three potential limiting flows have been identified and modeled using reduced control volume based analysis: (1) incipient reverse flow into the secondary inlet, (2) choked flow in the secondary inlet, and (3) choked flow in the exit mixing stream. Comparison of the methods developed here with the classical control volume portion of an ejector nozzle code have been performed and show good agreement. As such, it is concluded, that within the scope of one-dimensional cont

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29

Elangovan, S., and E. Rathakrishnan. "Studies on high speed jets from nozzles with internal grooves." Aeronautical Journal 108, no. 1079 (2004): 43–50. http://dx.doi.org/10.1017/s000192400000498x.

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Experiments were carried out on jets issuing from circular nozzles with grooved exits and the results compared with those of the plain nozzle. The plain nozzle had an exit diameter of 10mm. Because of the introduction of semi-circular grooves at the exit, the effective or equivalent diameter of the grooved nozzles was 10·44mm. The groove lengths were varied as 3, 5 and 8mm. The nozzles were operated at fully expanded sonic and underexpanded exit conditions. The corresponding fully expanded Mach numbers were 1·0 and 1·41. The shock cell structure of the underexpanded jets from grooved nozzles a

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30

Ternova, K. V. "Effect of the length of truncated nozzle with a tip on its thrust characteristics." Technical mechanics 2022, no. 4 (2022): 26–34. http://dx.doi.org/10.15407/itm2022.04.026.

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Nowadays, for solving new problems, rocket engine nozzle developers are increasingly turning to non- traditional nozzle configurations that differ from the classic Laval one. A relatively new line in the design of supersonic nozzles is the development of the so-called bell-shaped nozzle, which, unlike the classical Laval nozzle, has a larger angle of entry into the supersonic part of the nozzle. In this case, dual bell nozzles, which have two flow expansion sections in their supersonic part, are considered. However, the effect of the length ratio of the two flow expansion sections of a truncat

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31

Ihnatiev, O. D., N. S. Pryadko, G. O. Strelnikov, and K. V. Ternova. "Gas flow in a truncated Laval nozzle with a bell-shaped tip." Technical mechanics 2022, no. 2 (2022): 39–46. http://dx.doi.org/10.15407/itm2022.02.039.

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Flow in a truncated supersonic Laval nozzle with a bell-shaped tip (“bell”) is investigated. This nozzle configuration can be used in tight layouts of multistage rockets of short length with improved energy-mass characteristics. Similar types of nozzles were developed at the Institute of Technical Mechanics of the National Academy of Sciences and the State Space Agency of Ukraine in the 1990s. Using approximate methods, the parameters of variously configured truncated nozzles were calculated, and their models were made. Some of the models were blown with cold air, and their characteristics wer

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32

Stufflebeam, J. H., D. W. Kendrick, W. A. Sowa, and T. S. Snyder. "Quantifying Fuel/Air Unmixedness in Premixing Nozzles Using an Acetone Fluorescence Technique." Journal of Engineering for Gas Turbines and Power 124, no. 1 (1999): 39–45. http://dx.doi.org/10.1115/1.1396840.

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The ability of a lean-premixed combustion system to minimize emissions while maintaining combustion stability over the operating curve relies upon how well the fuel nozzle premixes the fuel and air. As the level of premixing increases, NOx emissions at a given flame temperature decrease until a perfectly premixed condition is achieved. The objective of this paper is to quantify the level of premixing achieved by a premixing nozzle using an acetone fluorescence technique and determine its relationship to NOx emissions and combustion stability. The technique of using acetone fluorescence has bee

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Riani, Novi Indah, Syamsuri Syamsuri, and Rungky Rianata Pratama. "Simulasi Numerik Aliran Melewati Nozzle Pada Ejector Converging – Diverging Dengan Variasi Diameter Exit Nozzle." R.E.M. (Rekayasa Energi Manufaktur) Jurnal 2, no. 1 (2017): 19. http://dx.doi.org/10.21070/r.e.m.v2i1.796.

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In the process of cooling or refrigeration, are required components where capable to flow the fluid to create a cycle of the cooling process. Among some of the vapor compression systems, the usage of ejector is the simplest system. Ejector has three main parts: primary nozzle, mixing chamber and diffuser. Various experiments of steam ejectors developed to increase the value of the COP. Entrainment ratio directly affects to the COP value generated by the system, where the geometric shapes and operating conditions in the steam ejector will affect to the value entrainment ratio. This research was

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34

Sukesan, Manu K., and Shine S. R. "Effect of back pressure and divergent section contours on aerodynamic mixture separation using convergent–divergent micronozzles." AIP Advances 12, no. 8 (2022): 085207. http://dx.doi.org/10.1063/5.0097772.

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A numerical investigation of the aerodynamic separation associated with converging–diverging two-dimensional planar micronozzles is reported. The impact of divergent section shapes such as linear, bell, and trumpet, the effect of different back pressure conditions, and the associated flow and separation features are studied. Simulations used the direct simulation Monte Carlo method and are validated with the available experimental data. The lateral separation effect is found to be influenced by the nozzle divergent section shape. The separation performance of micronozzles of different throat s

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35

Tuladhar, Upendra, Sang-Hyun Ahn, Dae-Won Cho, et al. "Analysis of Gas Flow Dynamics in Thermal Cut Kerf Using a Numerical and Experimental Approach for Nozzle Selection." Processes 10, no. 10 (2022): 1951. http://dx.doi.org/10.3390/pr10101951.

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Abstract (sommario):

Consistency in gas flow behavior under various operating conditions is expected for uniform cutting performance in the thermal cutting process. The slope of the cut front in the kerf slot of a sample cutting material varies with the operating condition which affects the gas flow pattern. Therefore, how the nozzle exit diameter and the slope of the cut front effects gas flow behavior has been studied using the Reynolds averaged Navier–Stokes (RANS) based k–ω turbulence model. Convergent–straight-type nozzles with exit diameters φexit of 1.5 mm, 2 mm and 2.5 mm were used to study the flow patter

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36

Seyed-Yagoobi, J., V. Narayanan, and R. H. Page. "Comparison of Heat Transfer Characteristics of Radial Jet Reattachment Nozzle to In-Line Impinging Jet Nozzle." Journal of Heat Transfer 120, no. 2 (1998): 335–41. http://dx.doi.org/10.1115/1.2824253.

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Abstract (sommario):

The heat transfer characteristics of three submerged radial jet reattachment (RJR) nozzles with exit angles of +45, 0, and −10 deg are compared to the heat transfer characteristics of a conventional submerged in-line jet (ILJ) nozzle. The nozzles are compared at their favorable spacing from the impingement surface. The comparisons are based on two criteria: (1) identical fluid flow power, and (2) identical peak pressure exerted on the impingement surface. The local and area-averaged Nusselt numbers are presented. Experiments were conducted for two different flow power conditions. Comparison un

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37

Weightman, Joel L., Omid Amili, Damon Honnery, Daniel Edgington-Mitchell, and Julio Soria. "Nozzle external geometry as a boundary condition for the azimuthal mode selection in an impinging underexpanded jet." Journal of Fluid Mechanics 862 (January 11, 2019): 421–48. http://dx.doi.org/10.1017/jfm.2018.957.

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Abstract (sommario):

The role of the external boundary conditions of the nozzle surface on the azimuthal mode selection of impinging supersonic jets is demonstrated for the first time. Jets emanating from thin- and infinite-lipped nozzles at a nozzle pressure ratio of $3.4$ and plate spacing of $5.0D$, where $D$ is the nozzle exit diameter, are investigated using high resolution particle image velocimetry (PIV) and acoustic measurements. Proper orthogonal decomposition is applied to the PIV fields and a difference in dominant instability mode is found. To investigate possible explanations for the change in instabi

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38

Nasire, Najim, Mehdi Jadidi, and Ali Dolatabadi. "Numerical Analysis of Cold Spray Process for Creation of Pin Fin Geometries." Applied Sciences 14, no. 23 (2024): 11147. http://dx.doi.org/10.3390/app142311147.

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A numerical study was performed to analyze the particle deposition of a cold spray process for the preparation of nickel electrocatalysts used in the Hydrogen Evolution Reaction (HER). The study focused on the creation of fin-shaped geometries with an optimal porosity on the electrode surface using a mask located between the nozzle exit and the substrate. Computational Fluid Dynamics (CFD) was performed on a three-dimensional high-pressure nozzle, with nickel powder used as the injection feedstock. The behavior of particles was effectively modeled through a two-way coupled Eulerian–Lagrangian

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39

Chen, W. L., W. H. Huang, and W. H. Lai. "Investigation of flow characteristics of various-aspect-ratio rectangular nozzles with an aft deck." Shock Waves 34, no. 6 (2024): 527–38. https://doi.org/10.1007/s00193-024-01188-z.

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Abstract (sommario):

AbstractThis study presents an experimental and numerical investigation to characterize the plume pattern of a high-aspect-ratio rectangular convergent/divergent nozzle with an aft deck in under-expanded conditions. The function of an aft deck is to shield the infrared signal of an exhaust plume at its strongest intensity located at the immediate downstream region of the nozzle exit. However, this practice may cause undesirable plume deflection, which needs to be reduced as much as possible. The nozzle pressure ratios ranged from 2 to 4, and the effect of the nozzle exit aspect ratio was exami

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40

Ihnatiev, O. D., N. S. Pryadko, G. O. Strelnikov, and K. V. Ternova. "Thrust characteristics of a truncated Laval nozzle with a bell-shaped tip." Technical mechanics 2022, no. 3 (2022): 35–46. http://dx.doi.org/10.15407/itm2022.03.035.

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Abstract (sommario):

This paper presents the results of a thrust performance study of an unconventionally shaped supersonic nozzle in the form of a truncated Laval nozzle with a bell-shaped tip. This nozzle shape may be used in the development of compact layouts of multistage rockets. The study was carried out using the ANSYS software package in a 3D formulation. The methodological approaches to the numerical calculation of a complex separated gas flow used in this study were verified in a previous study of the flow pattern in similar nozzle. Some results of exact calculations were compared with the results of exp

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41

Kozlov, V. V., A. V. Dovgal, M. V. Litvinenko, Yu A. Litvinenko, and A. G. Shmakov. "DIFFUSION COMBUSTION OF A HYDROGEN MICROJET, OUTFLOWING FROM A CURVLINEAR CHANNEL." Доклады Российской академии наук. Физика, технические науки 513, no. 1 (2023): 72–75. http://dx.doi.org/10.31857/s2686740023060123.

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Abstract (sommario):

The presented work examines the combustion of a hydrogen microjet flowing from a curved channel with a round micronozzle. Jet flows that are generated using rectilinear and curved channels differ in that in the second case, Dean vortices make a noticeable contribution to the formation of the jet and its combustion. The interaction of the latter with Kelvin–Helmholtz vortices, the formation of which is typical for flows with a velocity shift, causes changes in combustion characteristics. They include spatial distortions of the laminar flame zone near the nozzle exit, the area of turbulent combu

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42

Trabold, T. A., and N. T. Obot. "Evaporation of Water With Single and Multiple Impinging Air Jets." Journal of Heat Transfer 113, no. 3 (1991): 696–704. http://dx.doi.org/10.1115/1.2910620.

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Abstract (sommario):

An experimental investigation of impingement water evaporation under a single jet and arrays of circular jets was made. The parametric study included the effects of jet Reynolds number and standoff spacing for both single and multiple jets, as well as surface-to-nozzle diameter ratio and fractional nozzle open area for single and multiple jets, respectively. The nozzle exit temperature of the air jet, about the same as that of the laboratory, was 3–6° C higher than that of the evaporating water. Predictive equations are provided for mass transfer coefficient in terms of the flow and geometric

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43

Hutli, Ezddin, Salem Abouali, Ben Hucine, Mohamed Mansour, Milos Nedeljkovic, and Vojislav Ilic. "Influences of hydrodynamic conditions, nozzle geometry on appearance of high submerged cavitating jets." Thermal Science 17, no. 4 (2013): 1139–49. http://dx.doi.org/10.2298/tsci120925045h.

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Abstract (sommario):

Based on visualization results of highly-submerged cavitating water jet obtained with digital camera, the influences of related parameters such as: injection pressure, nozzle diameter and geometry, nozzle mounting (for convergent / divergent flow), cavitation number and exit jet velocity, were investigated. In addition, the influence of visualization system position was also studied. All the parameters have been found to be of strong influence on the jet appearance and performance. Both hydro-dynamical and geometrical parameters are playing the main role in behavior and intensity of cavitation

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44

Daubner, Tomas, Jens Kizhofer, and Mircea Dinulescu. "Experimental investigation of five parallel plane jets with variation of Reynolds number and outlet conditions." EPJ Web of Conferences 180 (2018): 02018. http://dx.doi.org/10.1051/epjconf/201818002018.

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Abstract (sommario):

This article describes an experimental investigation in the near field of five parallel plane jets. The study applies 2D Particle Image Velocimetry (PIV) for ventilated and unventilated jets, where ventilated means exiting into a duct with expansion ratio 3.5 and unventilated means exiting to the free atmosphere. Results are presented for Reynolds numbers 1408, 5857 and 10510. The Reynolds number is calculated for the middle channel and is based on the height of the nozzle (channel) equivalent diameter 2h. All characteristic regions of the methodology to describe multiple interacting jets are

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45

Knowles, K., and L. Kirkham. "Inverted-profile coaxial jet flows relevant to Astovl applications." Aeronautical Journal 102, no. 1017 (1998): 377–84. http://dx.doi.org/10.1017/s0001924000065155.

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Abstract (sommario):

AbstractAn experimental investigation has been performed into the free jet and wall jet characteristics of high pressure ratio coaxial jets operating with inverted velocity profiles and impinging onto a ground plane. Pitot-static probes have been used to record free jet properties at various distances from the jet exit plane, and wall jet properties of the impinging jets at various radial positions. Jet properties such as velocity decay and spreading rates were calculated and compared to published literature. Wall jet development was investigated and recorded. Inner and outer nozzle pressure r

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46

Ternova, K. V. "Effect of the tip geometry of a truncated supersonic nozzle on its characteristics." Technical mechanics 2023, no. 2 (2023): 32–40. http://dx.doi.org/10.15407/itm2023.02.032.

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Abstract (sommario):

Truncated nozzles are used for tight packing of the rocket engine. Such nozzles have a profiled tip to maximize the filling of space and reduce the overall weight. This paper is concerned with the study the effect of the tip geometry of a truncated supersonic nozzle on its characteristics. The features of the gas flow at different initial pressures and different environmental conditions in the supersonic area of a nozzle with a bell-shaped tip of different lengths are considered. The flow inside the nozzle followed by the jet outflow into the surrounding space was simulated. The flow simulatio

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47

Ranjan, Abhash, Mrinal Kaushik, Dipankar Deb, Vlad Muresan, and Mihaela Unguresan. "Assessment of Short Rectangular-Tab Actuation of Supersonic Jet Mixing." Actuators 9, no. 3 (2020): 72. http://dx.doi.org/10.3390/act9030072.

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Abstract (sommario):

This work explores the extent of jet mixing for a supersonic jet coming out of a Mach 1.8 convergent-divergent nozzle, controlled with two short rectangular vortex-generating actuators located diametrically opposite to each other with an emphasis on numerical methodology. The blockage ratio offered by the tabs is around 0.05. The numerical investigations were carried out by using a commercial computational fluid dynamics (CFD) package and all the simulations were performed by employing steady Reynolds-averaged Navier–Stokes equations and shear-stress transport k−ω turbulence model on a three-d

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48

Kang, Jun Seok, and Chi Young Lee. "Investigation on Effects of Water Mist Characteristics According to Axial Position on Thermal Radiation Attenuation Performance." Fire Science and Engineering 36, no. 3 (2022): 11–18. http://dx.doi.org/10.7731/kifse.32592e18.

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Abstract (sommario):

In this study, the effects of water mist characteristics according to the axial position on thermal radiation attenuation performance were experimentally investigated using the single-fluid nozzle. Under the water flow rate conditions of 200∼350 g/min, the thermal radiation attenuation performance was measured at the axial position (i.e., downstream direction of water mist from nozzle exit) of 200∼1000 mm. In addition, during the discharge of water mist, the water supply pressure and droplet size of water mist were measured and the water mist was visualized. As a result, with an increase in th

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49

Ghazwani, Hassan Ali, Khairuddin Sanaullah, and Afrasyab Khan. "Hydrodynamics of Supersonic Steam Jets Injected into Cross-Flowing Water." Fluids 8, no. 9 (2023): 250. http://dx.doi.org/10.3390/fluids8090250.

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Abstract (sommario):

High-speed gas/vapour jets injected into a cross-moving sonic liquid signifies a vital phenomenon which bears useful applications in environmental and energy processes. In the present experimental study, a pulsating jet of supersonic steam was injected into cross-flowing water. Circulation zones of opposite vorticity owing to the interaction between the steam jet and cross-water flow were found. However, a large circulation appeared in front of the nozzle exit. Also, most small circulation regions were observed at higher water-flow rates (>2 m3/s). Among the prime mixing variables (i.e., tu

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50

Chen, J. L., M. Wells, and J. Creehan. "Primary Atomization and Spray Analysis of Compound Nozzle Gasoline Injectors." Journal of Engineering for Gas Turbines and Power 120, no. 1 (1998): 237–43. http://dx.doi.org/10.1115/1.2818082.

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Abstract (sommario):

This work addresses primary atomization modeling, multidimensional spray prediction, and flow characteristics of compound nozzle gasoline injectors. Compound nozzles are designed to improve the gasoline spray quality by increasing turbulence at the injector exit. Under the typical operating conditions of 270-1015 kPa, spray atomization in the compound nozzle gasoline injectors is mainly due to primary atomization where the flow turbulence and the surface tension are the dominant factors. A primary atomization model has been developed to predict the mean droplet size far downstream by taking in

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