Effect Of Nozzle Parameters Research Articles

The Study of Assessment Parameters and Performance Measurement of Cold Spray Technique: A Futuristic Approach Towards Additive Manufacturing

In recent years, high-performance additive manufacturing (AM) is being extensively investigated by the virtue of its unique benefits over traditional manufacturing processes. Complex components of Ti, Fe, Ni alloys can be manufactured with ease; however, other nonferrous alloys such as Al alloys, Mg alloys, and Cu alloys have the melting tendency during processing by laser, electron beam, or arc, hence not appropriate to be manufactured using additive manufacturing. The most useful and powerful tool recognized in AM in the last decade is the cold spray process. This paper puts forth a review of recent research innovations and the concept to build new materials in the field of AM technology. The author has highlighted the important properties including retention of original feedstock particles and oxide-free surface deposits during the entire coating process. The present research work focuses on the basic principle, bonding mechanism and impact phenomenon, and effect of nozzle parameters on mechanical properties of deposits associated with cold spray additive manufacturing. Furthermore, the concept to develop well-bonded coated deposits and its metallurgical behavior have also been studied. Various aspects of repair and maintenance against corrosion and wear along with strength and geometry restoration have also been highlighted in this paper.

EFFECT OF NOZZLE PARAMETERS ON THE SPRAY CHARACTERISTICS FOR SMALL-SCALED AVIATION KEROSENE ROTARY ENGINE

EFFECT OF NOZZLE PARAMETERS ON THE SPRAY CHARACTERISTICS FOR SMALL-SCALED AVIATION KEROSENE ROTARY ENGINE

Failure Mechanism and Effect of Nozzle Parameters on Abrasive Water Jet Rock Breaking

Abrasive Water Jet (AWJ) technology has vast application prospects in the assisted drill-blasting of tunnel excavation, with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility. Nevertheless, AWJ technology has some limitations and shortcomings, such as the small effective fracturing range and parameter mismatch, which influence the fracturing effect of AWJ. To solve the abovementioned issues, it is necessary to study the failure mechanism of rock impacted by AWJ and nozzle parameter effects on rock fragmentation. Based on the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), in this research, the numerical model of AWJ impacting rock was established, and the result was verified with Computed Tomography (CT) scanning after the AWJ impacting rock experiment and image processing technology. Through the analysis of the stress characteristics of typical particles in the rock model at different stages and positions, the formation and expansion mechanisms of the crater and the cracks were revealed. Additionally, in this research, the comprehensive damage factor of rock (X) representing the fragmentation degree was defined. By comparatively analyzing X-values with certain technical parameters of AWJ, the importance ranking of the nozzle parameters, the effect of each nozzle parameter on the rock fragmentation, and the optimal parameter combination were also investigated.

The movement and forces of spinning solution in the nozzle during high-speed centrifugal spinning

High-speed centrifugal spinning is a novel method to fabricate nanofiber. It has the potential to fabricate nanofiber on a large scale because its production efficiency is much greater than traditional methods. Nozzle is an important part of high-speed centrifugal spinning equipment because its length, shape, and diameter all will affect the morphology and quality of nanofiber. It is useful to study the movement and forces of spinning solution in the nozzle. In this article, the principle and equipment structure of high-speed centrifugal spinning are briefly introduced at first. Then the movement and forces of spinning solution are analyzed by establishing parametric model at nozzle. It can be found that the spinning solution is ejected from nozzle when the rotating speed reaches a critical value. The critical rotating speed is inversely proportional to the radius of nozzle and directly proportional to the viscosity of spinning solution. There are several nozzle structures proposed and compared for nozzle optimization. Finally, the effects of nozzle parameters, concentration of spinning solution, and rotational speed on the morphology of nanofiber are verified by high-speed centrifugal spinning experiments. It lays the foundation for optimizing spinning equipment.

Predicting the Tensile Properties of Air-Jet Spun Yarns

Two modeling methods are used to predict the tensile properties of air-jet spun yarns. A numerical simulation provides a useful insight into the flow characteristics and wrap ping formation process of edge fibers in the nozzle of an air-jet spinning machine. By analyzing the results of the numerical simulation, the effects of nozzle parameters on yarn tensile properties can be predicted. A neural network model provides quantitative predic tions of yarn tenacity. The effects of parameters on yarn tenacity are also determined by the neural network model. Excellent agreement is obtained between these two methods.

Characteristics of impact driven supersonic liquid jets

In this paper, a technique for the generation of supersonic liquid (water and diesel fuel) jets is presented. The supersonic liquid jet is generated by the use of a purpose-developed vertical, single-stage powder gun. The characteristics and behavior of supersonic liquid jets were obtained by visualization using the shadowgraph technique. The visual evidence related to supersonic liquid jets (velocity around 2000 m/s) generated from a variety of nozzle types is presented and the effects of nozzle parameters on the jet behavior are described. The characteristics of the leading edge shock wave and jet shape were found to be significantly related to the nozzle geometry. A one-dimensional analysis of the multiple, reflected shock waves inside the liquid sac and nozzle during the process of supersonic jet generation is presented. The method allows impact pressure, particle velocity and effect of shock wave reflections inside the nozzle cavity on the liquid jet velocity to be obtained. Jet shock waves obtained from the shadowgraph image and CFD simulation are also compared. The jet outflow characteristics and its leading edge shock wave in air were assessed for their potential for auto-ignition using fuel with cetane numbers from 50–100. The contribution of the strong leading edge shock wave to the auto-ignition is discussed.

Water modelling study of the jet characteristics in a continuous casting mould

The jet characteristics and the fluid flow pattern in a continuous slab caster have been studied using a water model. The fluid jet is studied under free fall and submerged discharge conditions. In the latter case, the jet was followed by dye-injection technique and image analyser was used to find out the effect of nozzle parameters on jet-spread angle, jet-discharge angle and the volume entrainment by the jet. All free-fall jets with nozzle port angle zero and upward are found to be spinning. Some of the free-fall jets with downward nozzle-port angle are found to be spinning and rest are smooth. The spinning direction of the jets are found to change with time. The well depth, port diameter and the inner diameter of the nozzle have a clear effect on the free-fall jets with downward port angle. The jet-spread angle is found to be about 17° for smooth jets. The spread angle for spinning jet increases as the nozzle-port angle is increased from downward 25 to upward 15°. The jet-discharge angle is always downward even when the nozzle-discharge ports are angled upward. The extent of volume entrainment by the spinning jet is higher and it increases as the nozzle-port angle is increased from 25 downward to 15° upward. Strahleigenschaften und Strömungsbilder in der Stranggießkokille wurden anhand eines Wassermodells studiert. Dabei wird sowohl das Freistrahlverhalten als auch das verdeckte Gießen betrachtet. Beim verdeckten Gießen wurde der Strahl mit Hilfe von Farbeinspritzungen verfolgt. Die Bildanalyse diente zur Ermittlung des Einflusses der Düsenparameter auf den Strahlwinkel, Strahlaustrittswinkel wie auch auf die Menge des mitgenommenen Volumens. Es zeigte sich, daß beim Freistrahl mit einem Öffnungswinkel ≥ Null Verwirbelungen auftreten. Auch bei einigen Freistrahlen mit abwärts gerichtetem Düsenöffnungswinkel traten solche Verwirbelungen auf, die restlichen waren glatt. Die Richtung der Verwirbelungen änderte sich mit der Zeit. Eintauchtiefe, Öffnungsdurchmesser und der innere Düsendurchmesser beeinflussen deutlich das Freistrahlverhalten bei abwärts gerichtetem Öffnungswinkel. Der Strahldurchmesser beträgt bei glattem Strahl etwa 17°. Bei verwirbeltem Strahl steigt der Strahlwinkel mit zunehmendem Düsenöffnungswinkel von − 25 bis zu + 15° an. Das Ausmaß der Volumenmitnahme ist im Falle des verwirbelten Strahls größer und steigt mit zunehmendem Düsenauslaßwinkel.

Effects of nozzle parameters and shape on the gain in a gasdynamic laser using combustion products from liquid hydrocarbons

Effects of nozzle parameters and shape on the gain in a gasdynamic laser using combustion products from liquid hydrocarbons