Spray Pattern of Aluminum Coatings with the Rectangular Cross-Section Nozzle Calculated by the Computational Fluid Dynamics (CFD) in High-Pressure Cold Spray

2021 ◽  
Author(s):  
Kazuhiko Sakaki ◽  
Tomiki Tsubata ◽  
Hikaru Isogami ◽  
Koki Matsuda
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Cold Spray ◽  
Aluminum Particles ◽  
Rectangular Section ◽  
Cross Sectional ◽  
Spray Pattern ◽  
Rectangular Nozzle ◽  
Computational Fluid Dynamics Cfd

Abstract In the cold spray process; cross-sectional shape of the nozzle has a significant effect on spray pattern of coatings. The circular exit nozzle is parabolic in shape. So; spray pattern with the rectangular nozzle is wider than that with the circular spray nozzle. The goal of this investigation is to establish a design for the cold spray gun nozzle to gain more uniform spray profile of coatings. We have investigated the influence of expansion ratio; nozzle total length and the ratio of nozzle length of divergent section and parallel section of rectangular nozzle on behaviors of gas and particle by the computational fluid dynamics (CFD) in high pressure cold spraying. We have studied copper particles so far. In this study; we will examine aluminum particles. First; we investigate the influence of the size and shape of the rectangular section nozzle on the velocity; temperature; and particle distribution of aluminum particles by CFD. After that; the rectangular section nozzles were fabricated and coating formation experiments were conducted; spray patterns and coating cross-sectional structures were observed; and coating adhesion was also evaluated. The nozzle material was polybenzimidazole resin; which is difficult for aluminum particles to attach to nozzle walls.

Effect of Bilge Radius and Bilge Keel Height on Roll Damping Performance of Floating Structures

2021 ◽  
Author(s):  
Chang Seop Kwon ◽  
Joo-Sung Kim ◽  
Hyun Joe Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Floating Body ◽  
Rectangular Section ◽  
Roll Damping ◽  
Floating Structures ◽  
Free Decay ◽  
Computational Fluid Dynamics Cfd ◽  
Bilge Keel

Abstract A round bilge with a bilge keel structure is a key element which can alleviate roll motions of ships and floating structures by transferring the roll momentum of a floating body into the kinetic energy of water. This study presents a practical guide to properly designing a bilge radius and bilge keel height of a barge-shaped and tanker-shaped FPSOs. A parametric study to figure out the effect of bilge radius and bilge keel height on the roll damping performance is conducted through a series of numerical roll free decay simulations based on Computational Fluid Dynamics (CFD). The bilge radius is normalized by the half breadth of ship, and the bilge keel height is normalized by the maximum bilge keel height which is limited by the molded lines of a side shell and bottom shell. In addition, it is investigated to identify how the roll damping performance of a rectangular section differs from the result of a typical round bilge section with maximum available bilge keel height.

scholarly journals Analysis of a Converging, Annular, Isothermal Melt Blowing Jet Using Computational Fluid Dynamics

2005 ◽  
Vol os-14 (3) ◽  
pp. 1558925005os-14
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Near Field ◽  
Flow Characteristics ◽  
Sectional Area ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Cfd

An unconventional melt blowing die was analyzed using computational fluid dynamics (CFD). This die has an annular configuration wherein the jet inlet is tapered (the cross-sectional area decreases) as the air approaches the die face. It was found that the flow characteristics of this die are different from conventional slot and annular dies. In particular, for the tapered die the near-field normalized turbulent kinetic energy was found to be lower at shallow die angles. Also, it was found that the peak mean velocity behavior was intermediate between that of conventional annular and slot dies. The centerline turbulence profiles were found to be qualitatively similar to those of annular dies; quantitatively, higher values were present for tapered dies.

Effects of Volute Cross-Sectional Area Distribution on Performance of Double-Suction Volute Pump

2019 ◽  
Author(s):  
Szu Yung Chen ◽  
Lu Zhang ◽  
Yumiko Sekino ◽  
Hiroyoshi Watanabe
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Computational Fluid Dynamics ◽  
Secondary Flow ◽  
Cross Sections ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Suction Pump ◽  
Computational Fluid Dynamics Cfd

Abstract The following study describes the optimization design procedure of a double-suction pump. BASELINE pump is designed as inlet nozzle diameter 800 mm and impeller outlet diameter 740 mm. Each component of a BASELINE pump, impeller configurations, discharge volute, and the suction casing were determined by DOE (Design of Experiments) and sensitivity analysis. However, finite selected design parameters for each component are mostly restricted to the free surface design of the pump casing. In this study, the optimization method approach along with steady Computational Fluid Dynamics (CFD) is introduced to achieve the high efficiency request of a double-suction pump. To investigate the matching optimization of the impeller and discharge volute at design point, the full parametric geometry of discharge volute was developed referred to the BASELINE shape and Multi-Objective Genetic Algorithm NSGA-II (Non-dominated Sorting Genetic Algorithm II) was used. Optimization result shows that by increasing the volute cross-sectional area from the volute tongue till the circumferential angle 180 deg. provides lower loss. This is due to the improvement achieved for the better distribution of the velocity gradient within the volute. A validated unsteady computational fluid dynamics (CFD) was also employed to investigate the performance difference between optimized volute design and the BASELINE which correlated to the pressure fluctuation and secondary flow behavior inside the cross-sections from 80% to 120% of nominal flow rate. The result shows that the flow distortion in the streamwise direction is stronger with the BASELINE and sensitively affects the operation stability. This is due to the different secondary flow pattern in the cross-sections, hence demonstrating a design direction of desired volute cross-sectional shape for high-performance can be used in a double-suction volute pump.

Influence Mechanisms of Manufacture Variations on Supersonic/Transonic Blade Aerodynamic Performances

2020 ◽  
Author(s):  
Baojie Liu ◽  
Jiaxin Liu ◽  
Xianjun Yu ◽  
Dejun Meng ◽  
Wenbin Shi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Statistical Analysis ◽  
Mach Number ◽  
Systematic Errors ◽  
Aerodynamic Performance ◽  
Aerodynamic Performances ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Abstract The results of previous studies have proved that manufacture variations can cause a noticeable influence on compressor aerodynamic performance. The main objective of this paper is to investigate the influence rules and mechanisms of manufacture variations on supersonic/transonic blades aerodynamic performance. The variations used in this study were measured from some newly manufactured high-pressure compressors. In the present study, several blade sections with different design Mach number conditions are selected for further statistical analysis of measured deviation data. Therefore, some systematic errors in the deviation data have been revealed. Based on these data, the computational fluid dynamics (CFD) method has been used to obtain the aerodynamic performances of a large number of the measured blade elements. And then, the analysis of the influence rules of manufacture variations on blade aerodynamic performance in different Mach number conditions has been carried out. The present results indicate that the effects of manufacture variations on blade aerodynamic performance in the lower Mach number (0.8) condition are much more significant comparing to that in the higher Mach number (0.9∼1.2) conditions. Based on this, influence mechanisms of manufacture variations on positive incidence range and negative incidence range have been analyzed. The differences of influence mechanisms in different Mach number conditions are the focus of research.

Computational Investigation of Gas- Solid Flow in PFBC Plant

2006 ◽  
Author(s):  
M. H. Al-Hajeri
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Filter Cake ◽  
Particle Distribution ◽  
Computational Investigation ◽  
Filter Surface ◽  
Ceramic Candle Filter ◽  
Computational Fluid Dynamics Cfd ◽  
High Temperature High Pressure

This paper reports a computational Fluid Dynamics (CFD) investigation for a high-temperature high-pressure filtration (ceramic candle filter). However parallel flow to the filter is considered in this study. Different face (filtration) velocities are examined using the CFD code, FLUENT. Particles ranging from 1 to 100 microns are tracked through the domain to find the height at which the particles will impinge on the filter surface. Furthermore, particle distribution around the filter (or filter cake) is studied to design efficient cleaning mechanisms. Gravity affect to the particles with various inlet velocities and pressure drop are both considered.

On Deriving High Pressure Empirical Multiphase Forcing Functions From CFD Analysis

2019 ◽  
Author(s):  
Olivier Macchion ◽  
Stefan Belfroid ◽  
Leszek Stachyra ◽  
Atle Jensen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Pipe Flow ◽  
Experimental Results ◽  
Internal Diameter ◽  
Cfd Analysis ◽  
Empirical Correlations ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd

Abstract Computational Fluid Dynamics (CFD) simulations are used to predict the flow-induced forcing in high-pressure multiphase pipe flow. Furthermore, empirical correlations from the literature is compared and validated against computational and experimental results. Based on the CFD results and in conjunction with the reference 6” (internal diameter (ID)) data, new scaling rules are proposed.

Semi-Empirical Approach to Predicting Temperatures of a Non-Opaque Surface

2002 ◽  
Author(s):  
Bob Bush ◽  
Shu Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Analytical Techniques ◽  
Harsh Environments ◽  
Total Power ◽  
Computational Fluid Dynamics Cfd ◽  
Energy Equations ◽  
Semi Empirical ◽  
Opaque Surface

The methods used in predicting the thermal profile of a high-pressure mercury arc lamp housed in an electronics enclosure are discussed. These types of enclosures are typically operated in harsh environments. High temperature and low pressure air is typically used to cool the electronics inside. A lamp, which dissipates roughly one half of the total power within the box, must be cooled sufficiently so as to not affect the performance of the circuit cards. Since the majority of the heat being transferred from the lamp’s center arc tube to its surrounding atmosphere (to the lamp housing and then to the circuit cards inside the electronics box) is via radiation, a Computational Fluid Dynamics (CFD) code with a radiation solver was essential to drive the design. Fluent Icepak was chosen as a capable code for electronic box type problems. However, lcepak does not account for radiative transfer through non-opaque surfaces. Since the lamp housing is very transmissive in the infrared at certain wavelengths, the energy equations could not be solved using only analytical techniques. Therefore, tests were conducted that first characterized the thermal performance of the lamp and then predicted the energy that was conducted and absorbed by the glass housing (made up of a reflector and front cover). The remaining power was then assumed to be transmissive in nature. In the computational model, powers were iteratively applied to various locations on the lamp housing until the model matched the empirical results. Once the lamp model was characterized, it could be used to drive the design of any type of enclosure in any type of environment.

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