G0500-6-3 Numerical simulation on the influence of particle-diameter distributions on the deposition efficiency in cold spray

In this work, a study was carried out to compare the filtering and hydrodynamic properties of granular filters with solid spherical granules and spherical granules with modifications in the form of micropores. We used the discrete element method (DEM) to construct the geometry of the filters. Models of granular filters with spherical granules with diameters of 3, 4, and 5 mm, and with porosity values of 0.439, 0.466, and 0.477, respectively, were created. The results of the numerical simulation are in good agreement with the experimental data of other authors. We created models of granular filters containing micropores with different porosity values (0.158–0.366) in order to study the micropores’ effect on the aerosol motion. The study showed that micropores contribute to a decrease in hydrodynamic resistance and an increase in particle deposition efficiency. There is also a maximum limiting value of the granule microporosity for a given aerosol particle diameter when a further increase in microporosity leads to a decrease in the deposition efficiency.

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Numerical Simulation of Particles Deposition in a Human Upper Airway

Advances in Mechanical Engineering ◽

10.1155/2014/207938 ◽

2014 ◽

Vol 6 ◽

pp. 207938 ◽

Cited By ~ 1

Author(s):

Debo Li ◽

Qisheng Xu ◽

Yaming Liu ◽

Yin Libao ◽

Jin Jun

Keyword(s):

Numerical Simulation ◽

Nasal Cavity ◽

Particle Deposition ◽

Geometric Model ◽

Particle Diameter ◽

Upper Airway ◽

Deposition Efficiency ◽

Particle Movement ◽

Scanned Images ◽

Les Model

Based on the CT scanned images, a realistic geometric model from nasal cavity to upper six-generation bronchia is rebuilt. In order to effectively simulate the particle movement and deposition, LES model is used and the particles are tracked in the frame of Lagrange. Seven kinds of typical particles, including micron particles (1, 5, and 10 μm) and nanoparticles (1, 5, 20, and 100 nm), and three representative respiratory intensities are adopted as computational case, respectively. Deposition efficiency ( D E), deposition concentration ( D C), and capture efficiency ( C E) are introduced. Furthermore, the locations of particle deposition are visualized. The results indicate that the injecting particles from different nasal inlet present “transposition effect.”The D E values of micron particles are much higher than nanoparticles. The particle diameter plays a weaker role in nanoparticle depositions than micron particles. The highest values of D E and D C both occur in nasal cavity, while the highest C E up to 99.5% occurs in bronchus region.

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Effects of Gun Nozzle Geometry on High Velocity Oxygen-Fuel (HVOF) Thermal Spraying Process

Thermal Spray 1998: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc1998p0445 ◽

1998 ◽

Author(s):

K. Sakaki ◽

Y. Shimizu ◽

Y. Gouda ◽

A. Devasenapathi

Keyword(s):

Numerical Simulation ◽

Experimental Studies ◽

Thermal Spraying ◽

Deposition Efficiency ◽

Divergence Angle ◽

Nozzle Geometry ◽

Oxide Content ◽

Hvof Thermal Spraying ◽

Throat Diameter ◽

Spraying Process

Abstract Effect of nozzle geometry (such as throat diameter of a barrel nozzle, exit diameter and exit divergence angle of a divergent nozzle) on HVOF thermal spraying process (thermodynamical behavior of combustion gas and spray particles) was investigated by numerical simulation and experiments with Jet KoteTM II system. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A NiCrAIY alloy powder was used for the experimental studies. While the throat diameter of the barrel nozzle was found to have only a slight effect on the microstructure, hardness, oxygen content and deposition efficiency of the coatings, the change in divergent section length (rather than exit diameter and exit divergence angle) had a significant effect. With increase in divergent section length of the nozzle, the amount of oxide content of the NiCrAIY coatings decreased and the deposition efficiency increased significantly. Also, with increase in the exit diameter of the divergent nozzle, the gas temperature and the degree of melting of the particle decreased. On the other hand the calculated particle velocity showed a slight increase while the gas velocity increased significantly.

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Novel Powder Modification Method for the Cold Spray of Hard Steels

10.31399/asm.cp.itsc2021p0603 ◽

2021 ◽

Author(s):

D. Poirier ◽

Y. Thomas ◽

B. Guerreiro ◽

M. Martin ◽

M. Aghasibeig ◽

...

Keyword(s):

Heat Treatment ◽

Cold Spray ◽

Steel Powder ◽

Deposition Efficiency ◽

Maximum Temperature ◽

Powder Size ◽

H13 Tool Steel ◽

Treatment Conditions ◽

Dense Deposits ◽

Modification Method

Abstract A novel powder modification method based on the simultaneous softening and agglomeration of steel powders via heat treatment in a rotary tube furnace has been investigated as a means to improve the cold sprayability of H13 tool steel powder. By adjusting starting powder size and shape as well as heat treatment conditions (maximum temperature, cooling rate, and atmosphere), cold spray of H13 powder went from virtually no deposition to the production of thick dense deposits with a deposition efficiency of 70%. Powder agglomeration, surface state, microstructure evolution, and softening are identified as key factors determining powder deposition efficiency and resulting deposit microstructure.

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Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.5.2203 ◽

1996 ◽

Vol 81 (5) ◽

pp. 2203-2213 ◽

Cited By ~ 71

Author(s):

Chong S. Kim ◽

S. C. Hu ◽

P. Dewitt ◽

T. R. Gerrity

Keyword(s):

Particle Diameter ◽

Deposition Efficiency ◽

Dead Volume ◽

Delivery Method ◽

Constant Flow Rate ◽

Inhaled Particles ◽

Human Lungs ◽

Regional Deposition ◽

Delivery Technique ◽

Deposition Fraction

Kim, Chong S., S. C. Hu, P. DeWitt, and T. R. Gerrity.Assessment of regional deposition of inhaled particles in human lungs by serial bolus delivery method. J. Appl. Physiol. 81(5): 2203–2213, 1996.—Detailed regional deposition of inhaled particles was investigated in young adults ( n = 11) by use of a serial bolus aerosol delivery technique. A small bolus (45 ml half-width) of monodisperse aerosols [1-, 3-, and 5-μm particle diameter ( D p)] was delivered sequentially to a specific volumetric depth of the lung (100–500 ml in 50-ml increments), while the subject inhaled clean air via a laser aerosol photometer (25-ml dead volume) with a constant flow rate (Q˙ = 150, 250, and 500 ml/s) and exhaled with the same Q˙ without a pause to the residual volume. Deposition efficiency (LDE) and deposition fraction in 10 local volumetric regions and total deposition fraction of the lung were obtained. LDE increased monotonically with increasing lung depth for all three D p. LDE was greater with smaller Q˙ values in all lung regions. Deposition was distributed fairly evenly throughout the lung regions with a tendency for an enhancement in the distal lung regions for D p = 1 μm. Deposition distribution was highly uneven for D p = 3 and 5 μm, and the region of the peak deposition shifted toward the proximal regions with increasing D p. Surface dose was 1–5 times greater in the small airway regions and 2–17 times greater in the large airway regions than in the alveolar regions. The results suggest that local or regional enhancement of deposition occurs in healthy subjects and that the local enhancement can be an important factor in health risk assessment of inhaled particles.

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Particle Deposition Characteristics and Efficiency in Duct Air Flow over a Backward-Facing Step: Analysis of Influencing Factors

Sustainability ◽

10.3390/su11030751 ◽

2019 ◽

Vol 11 (3) ◽

pp. 751

Author(s):

Hao Lu ◽

Li-zhi Zhang

Keyword(s):

Particle Deposition ◽

Air Flow ◽

Deposition Velocity ◽

Particle Diameter ◽

Deposition Efficiency ◽

Reynolds Stress Model ◽

Expansion Ratio ◽

Particle Model ◽

Duct Flow ◽

Backward Facing Step

Dry deposition of airborne particles in duct air flow over a backward-facing step (BFS) is commonly encountered in built environments and energy engineering. However, the understanding of particle deposition characteristics in BFS flow remains insufficient. Thus, this study investigated particle deposition behaviors and efficiency in BFS flow by using the Reynolds stress model and the discrete particle model. The influences of flow velocities, particle diameters, and duct expansion ratios on particle deposition characteristics were examined and analyzed. After numerical validation, particle deposition velocities, deposition efficiency, and deposition mechanisms in BFS duct flow were investigated in detail. The results showed that deposition velocity in BFS duct flow monotonically increases when particle diameter increases. Moreover, deposition velocity falls with increasing expansion ratio but rises with increasing air velocity. Deposition efficiency, the ratio of deposition velocity, and flow drag in a BFS duct is higher for small particles but lower for large particles as compared with a uniform duct. A higher particle deposition efficiency can be achieved by BFS with a smaller expansion ratio. The peak deposition efficiency can reach 33.6 times higher for 1-μm particles when the BFS expansion ratio is 4:3. Moreover, the “particle free zone” occurs for 50-μm particles in the BFS duct and is enlarged when the duct expansion ratio increases.

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Influence of a shape of single track on deposition efficiency of 316L stainless steel powder in cold spray

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2016.10.052 ◽

2017 ◽

Vol 309 ◽

pp. 951-958 ◽

Cited By ~ 17

Author(s):

D. Kotoban ◽

S. Grigoriev ◽

A. Okunkova ◽

A. Sova

Keyword(s):

Stainless Steel ◽

Cold Spray ◽

316L Stainless Steel ◽

Steel Powder ◽

Deposition Efficiency ◽

Stainless Steel Powder ◽

Single Track

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The Influence of Major Diameter Solid Particle on the Double-Channel Pump Performance

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D ◽

10.1115/ajk2011-22033 ◽

2011 ◽

Author(s):

Yi Li ◽

Qiaoling Cui ◽

Zuchao Zhu ◽

Zhaohui He ◽

Baoling Cui

Keyword(s):

Numerical Simulation ◽

Flow Rate ◽

Sliding Wear ◽

Volume Fraction ◽

Particle Volume Fraction ◽

Particle Diameter ◽

Wall Region ◽

Impeller Outlet ◽

Anticlockwise Direction ◽

Double Channel

Based on mixture model, the numerical simulation of solid-liquid two-phase flow in a double channel pump (Specific speed ns = 81) was carried out. The effects of particle diameter, particle volume fraction and flow rate on solid volume concentration distribution, relative velocity distribution and abrasion characteristics were studied. The results reveal that in the impeller, more particles concentrate at the nut of the shaft end and the edge of the impeller outlet. So those regions are worn seriously. The abrasive types are sliding wear on the impeller outlet edge and impact wear on the nut respectively. In the wall of the volute, the concentrated areas of particles move round the anticlockwise direction when the mixture flow rate is larger. The reason is the mixture velocity is larger as the flow rate increases, and meanwhile the centrifugal force and gravity force are invariable. So the particles move round the impeller rotational direction consequently. In the volute, particles concentrate on the tongue and wall region, especially on the sections I, II, V and VII. So the areas are easily worn out. The abrasive type is the heavy sliding wear in the volute wall. Numerical simulation results are consistent with the actual situation. It follows that the calculating method is feasible.

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