Academic literature on the topic 'Cold spray nozzles'
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Journal articles on the topic "Cold spray nozzles"
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Vadla, Sai Rajkumar, and Jeffrey Doom. "Analysis of Jet Characteristics Among Various Cold Spray Nozzles." Journal of Thermal Spray and Engineering 1, no. 1 (2018): 24–31. http://dx.doi.org/10.52687/2582-1474/115.
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This research is conducted mainly to analyze the jet characteristics of various cold spray nozzles. This study presents the theoretical and practical aspects of Cold Spray process modeling, discusses multiple numerical analysis research areas, and determines the significant parameters to be considered while developing a custom cold spray setup and exhibits analysis-based correlations. The simulations were performed on some meshes of different density using the SST turbulent model in Star CCM+ solver. For the first time, in this work, the jet characteristics inside a step drilled nozzle was presented; Furthermore, shock diamond formation was found inside the divergent section of step drilled nozzle which strongly influence the flow regime with sharp fluctuations. The comprehensive comparison between step drilled nozzle, conical nozzle and curved nozzle indicates that curved nozzle results in slightly higher nozzle exit velocity. However, results have suggested that the curved nozzle can achieve much higher velocities by optimizing the nozzle length.
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Lupoi, R., and W. O'Neill. "Powder stream characteristics in cold spray nozzles." Surface and Coatings Technology 206, no. 6 (December 2011): 1069–76. http://dx.doi.org/10.1016/j.surfcoat.2011.07.061.
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Hu, W. J., K. Tan, S. Markovych, and X. L. Liu. "Study of a Cold Spray Nozzle Throat on Acceleration Characteristics via CFD." Journal of Engineering Sciences 8, no. 1 (2021): F19—F24. http://dx.doi.org/10.21272/jes.2021.8(1).f3.
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Cold spray technology can obtain coatings in a solid state, suitable for deposition protection, repair, and additive manufacturing. In order to further expand the application areas of cold spraying nozzles, especially the inner surface of the components or areas where a Straight-line conical nozzle cannot be applied, because the study of the throat of the nozzle with the angle will directly reduce the total length of the nozzle (the horizontal direction), hence, the spray with the angle will show its advantage. This study discusses the influence of the throat structure of the conical cold spray nozzle on the acceleration characteristics, including the throat’s size, length, and angle. The results show the following. Firstly, under the premise of keeping the shrinkage ratio and divergence ratio unchanged at normal temperature, the throat diameter is between 2–6 mm in size, and the maximum growth rate exceeds 20 m/s. When the throat exceeds 6mm, the growth rate of the outlet slows down, and the growth rate is only 8 m/s. Secondly, the length of the throat has little effect on the acceleration characteristics, the total range fluctuated from 533 to 550 m/s, and 11 mm length of the throat is the closest to 0mm. Additionally, the 90° throat angle has the least effect on the acceleration characteristics. Finally, the particle trajectory is affected by inlet pressure, injection pressure, particle size, and other factors.
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Meyer, M., and R. Lupoi. "An analysis of the particulate flow in cold spray nozzles." Mechanical Sciences 6, no. 2 (August 11, 2015): 127–36. http://dx.doi.org/10.5194/ms-6-127-2015.
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Abstract. Cold Spray is a novel technology for the application of coatings onto a variety of substrate materials. In this method, melting temperatures are not crossed and the bonding is realized by the acceleration of powder particles through a carrier gas in a converging-diverging nozzle and their high energy impact over a substrate material. The critical aspect of this technology is the acceleration process and the multiphase nature of it. Three different nozzle designs were experimented under constant conditions and their performance simulated using Computational Fluid Dynamics tools. The Deposition Efficiency was measured using titanium as feedstock material and it was shown that it decreases with the cross-sectional throat area of the nozzle. Computational results based on a one-way coupled multiphase approach did not agree with this observation, while more sophisticated modelling techniques with two-way couplings can partially provide high-quality outcomes, in agreement with experimental data.
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Liu, Ruoxin, Rui Zhao, Yongle Nian, and Wenglong Cheng. "Experimental study on the effect of additives on the heat transfer performance of spray cold plate." Journal of University of Science and Technology of China 52, no. 1 (2022): 4. http://dx.doi.org/10.52396/justc-2021-0152.
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<p>The spray cold plate has a compact structure and high-efficiency heat exchange, which can meet the requirements of high heat flux dissipation of multiple heat sources, and is a reliable means to solve the heat dissipation of the next generation of chips. This paper proposes to use surfactants to enhance the heat transfer of the spray cold plate, and conduct a systematic experimental study on the heat transfer performance of the spray cold plate under different types and concentrations of additives. It was found that among the three surfactants, sodium dodecyl sulfate (SDS) can improve the heat transfer performance of the spray cold plate, and at the optimal concentration of 200ppm, the heat transfer coefficient of the spray cold plate was increased significantly by 19.8%. Both the n-octanol-distilled water and Tween 20-distilled water can reduce the heat transfer performance of the cold plate using multi nozzles. In addition, based on the experimental data, the dimensionless heat transfers correlations for the spray cold plate using additives were conducted, and the maximum errors of dimensionless correlations for using additives were 2.1%, 2.8%, and 5.4% respectively. This discovery provides a theoretical analysis and basis for the improvement of spray cold plates.</p>
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Cao, Congcong, Wenya Li, Zhengmao Zhang, Xiawei Yang, and Yaxin Xu. "Cold Spray Additive Manufacturing of Ti6Al4V: Special Nozzle Design Using Numerical Simulation and Experimental Validation." Coatings 12, no. 2 (February 6, 2022): 210. http://dx.doi.org/10.3390/coatings12020210.
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Cold spray additive manufacturing (CSAM) shows great potential in titanium-alloy production as it is a solid-state process. However, data published so far have demonstrated the difficulty of producing dense and high-strength Ti alloy parts. Our previous studies have shown that nozzle design together with high-cost helium propulsive gas plays a crucial role in particle acceleration. In this work, special nozzles for Ti alloy were designed and validated experimentally with commercially available Ti6Al4V powder. Simulation results show that particle impact temperature increases remarkably for a long convergent length, while particle kinetic energy slightly increases, which is validated by experiments. The relationship between the particle impact temperature and practice diameter shows the first increase and then decrease. The experimental results show that as the nozzle convergent section becomes longer, the edges of the single-pass deposits become smoother, and the width, density, deposition efficiency, and microhardness of the single-pass deposits increase.
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Lupoi, Rocco, Morten Meyer, Wessel W. Wits, and Shuo Yin. "The role of particles flow characteristics in the performance of cold spray nozzles." CIRP Annals 69, no. 1 (2020): 189–92. http://dx.doi.org/10.1016/j.cirp.2020.04.061.
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Liebersbach, Piotr, Alden Foelsche, Victor K. Champagne, Matt Siopis, Aaron Nardi, and David P. Schmidt. "CFD Simulations of Feeder Tube Pressure Oscillations and Prediction of Clogging in Cold Spray Nozzles." Journal of Thermal Spray Technology 29, no. 3 (February 2020): 400–412. http://dx.doi.org/10.1007/s11666-020-00992-0.
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Tanigoshi, L. K., and Hugo Aguilar. "Control of Twospotted Spider Mite on Azuki Bean, 1992." Insecticide and Acaricide Tests 18, no. 1 (January 1, 1993): 191. http://dx.doi.org/10.1093/iat/18.1.191.
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Abstract Seven chemicals and 1 combination were evaluated for control of TSSM at the Irrigated Agriculture Research and Extension Center, Prosser, Benton County, WA. Spray treatments were applied with a CO2-powered backpack sprayer calibrated to delivery 25 gal/acre at 60 psi from a 7.5 ft boom with 8 TXVS-8 conejet nozzles. A completely randomized design was used with 0.01 acre plots replicated 5 times. Treatments were applied on 19 Aug. TSSM females were sampled by randomly selecting 20 leaflets/plot. Leaflets were placed in paper bags and kept in a cold box until processed with a mite brushing machine. Plots were visually examined for evidence of phytotoxicity.
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Özdemir, Ozan Çağatay, Joseph Mitchell Conahan, and Sinan Müftü. "Particle Velocimetry, CFD, and the Role of Particle Sphericity in Cold Spray." Coatings 10, no. 12 (December 18, 2020): 1254. http://dx.doi.org/10.3390/coatings10121254.
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Implementation of the cold spray (CS) technology in manufacturing and repair creates a demand for reliable quality control and process monitoring measures. In this regard, particle size and impact velocity are undoubtedly the most important control parameters in CS. Several in-flight measurement systems for particle velocimetry are now available commercially for CS. These systems provide great potential to be used as a diagnostic tool for validating CS system performance in industrial applications. However, post processing the velocimetry data is required in many instances for achieving a complete understanding of the particle flow field. In this study, particle velocimetry is used in conjunction with computational fluid dynamics (CFD) simulations to: (i) identify the physical factors that dictate the particle velocity and its variability; (ii) develop high fidelity CFD models to accurately predict particle flight parameters that cannot be measured by available experimental tools; and (iii) present the capabilities of state-of-the-art velocimeters as a reliable diagnostic tool for measuring the consistency and repeatability of CS systems in manufacturing settings. In-flight particle size, location, and velocity are measured using a commercially available velocimeter for aluminum and copper particles sprayed with supersonic nozzles using helium, nitrogen, and air by two high pressure CS systems. As a result of this work, particle sphericity was clearly identified to have strong effects on particle velocity and to be one of the main factors of the variability of particle velocity. Furthermore, methods for building a high-fidelity 3D-CFD model was presented. CFD models were validated using particle velocimetry and schlieren imaging. Finally, particle velocimetry is shown to be a valid diagnostics tool for CS with systems capable of measuring in-flight particle velocities along with particle sizes. This article also outlines steps necessary for conducting cold spray process diagnostics repeatably and reliably.
Dissertations / Theses on the topic "Cold spray nozzles"
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Leblanc, Robert Samuel. "Influence of Nozzle Material and Spray Parameters on Pure Aluminum and Aluminum 7075 coatings using Cold Gas Dynamic Spray." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34202.
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Commercial airplanes are still using aluminum alloys as their primary structural material. Even if the used carbon fiber reinforced polymers is becoming more popular due to their extremely high strength to weight ratio, the majority of the existing flying fleet is still made out of aluminum alloys. This material was primarily used due to its high strength to weight ratio, ease to machine, excellent corrosion resistance properties and its high crash energy absorption. Aircraft components made of aluminum alloys are subjected to high stresses and harsh environments during flight, potentially leading them to crack and/or corrode. Presently, there is no industrial approved method to repair these components. Recycling damaged aircraft parts by repairing them would result in large cost savings for the industry. The present study was motivated by the potential use of the cold gas dynamic spray (CGDS) process to repair damaged aluminum 7075-T6 aircraft components. Two feedstock materials were used to repair this alloy in this research: pure aluminum and aluminum 7075. Pure aluminum is used in the aircraft industry on non-bearing components due to its extremely high corrosion resistance properties. Aluminum 7075 is the material of choice for structural applications due to its high strength. The results of this study show that CGDS could be potentially used to repair aluminum components on aircrafts. However, this research demonstrated that new commercially available equipments need to be further developed to successfully produce repaired components that meet the industry standards.
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Nastic, Aleksandra. "Repair of Aluminum Alloy Aerospace Components and Cold Gas Dynamic Spray Flow Distribution Study." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32998.
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Aluminum alloys have been used for decades in aircraft as they offer a wide range of properties explicitly developed to provide a set of characteristics adapted to structural and non-structural components. However, aircraft components inevitably undergo degradation during service due to their extensive use and exposure to harsh environments. Typical repair methods are either not efficient for large scale repairs due to their low material growth rate, not suitable for field repair or involve the use of high process temperatures. The present research aims at evaluating the cold gas dynamic spray (CGDS) as a potential repair technology to restore Al7075-T6 nose landing gear steering actuator threads found on the Boeing 757 aircraft. Moreover, it studies the suitability of using cold spray to deposit Al2024 material. The influence of process parameters and substrate surface preparation on the material deposition efficiency and resulting microstructural and mechanical repair properties is also evaluated.
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Roy, Jean-Michel L. "Development of Cold Gas Dynamic Spray Nozzle and Comparison of Oxidation Performance of Bond Coats for Aerospace Thermal Barrier Coatings at Temperatures of 1000°C and 1100°C." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20681.
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The purpose of this research work was to develop a nozzle capable of depositing dense CoNiCrAlY coatings via cold gas dynamic spray (CGDS) as well as compare the oxidation performance of bond coats manufactured by CGDS, high-velocity oxy-fuel (HVOF) and air plasma spray (APS) at temperatures of 1000°C and 1100°C. The work was divided in two sections, the design and manufacturing of a CGDS nozzle with an optimal profile for the deposition of CoNiCrAlY powders and the comparison of the oxidation performance of CoNiCrAlY bond coats. Throughout this work, it was shown that the quality of coatings deposited via CGDS can be increased by the use of a nozzle of optimal profile and that early formation of protective α-Al2O3 due to an oxidation temperature of 1100°C as opposed to 1000°C is beneficial to the overall oxidation performance of CoNiCrAlY coatings.
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Foelsche, Alden. "Nozzle Clogging Prevention and Analysis in Cold Spray." 2020. https://scholarworks.umass.edu/masters_theses_2/963.
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Cold spray is an additive manufacturing method in which powder particles are accelerated through a supersonic nozzle and impinged upon a nearby substrate, provided they reach their so-called critical velocity. True to its name, the cold spray process employs lower particle temperatures than other thermal spray processes while the particle velocities are comparably high. Because bonding occurs mostly in the solid state and at high speeds, cold spray deposits are distinguished for having low porosity and low residual stresses which nearly match those of the bulk material.
One complication with the cold spray process is the tendency for nozzles to clog when spraying (in general) low-melting-point or dense metal powders. Clogging occurs when particles collide with the inner nozzle wall and bond to it rather than bouncing off and continuing downstream towards the substrate. The particles accumulate and eventually plug the nozzle passage. Clogging is inconvenient because it interrupts the spraying process, making it impossible to complete a task. Furthermore, when particle buildup occurs inside the nozzle, the working cross-sectional area decreases, which decreases the flow velocity and therefore the particle velocity, ultimately jeopardizing the particles’ ability to reach critical velocity at the substrate.
In this work, computational fluid dynamics (CFD) is used to study various aspects of nozzle clogging. Nozzle cooling with supercritical CO2 as the refrigerant is investigated as a means to prevent clogging. The effects of nozzle cooling on both the driving gas and the particles are addressed. Simplified pressure oscillations at the nozzle inlet are imposed to determine whether such oscillations, if present, can cause clogging. Subsequently, more realistic and complicated flow oscillations are introduced to isolate a potential root cause of clogging. Finally, several novel nozzle internal geometries are evaluated for their effectiveness at preventing clogging. A recommendation is provided for a nozzle to be tested experimentally because it might completely prevent clogging.
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Bush, Trenton. "Cold Gas Dynamic Spray – Characterization of Polymeric Deposition." 2016. https://scholarworks.umass.edu/masters_theses_2/413.
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When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure, and plastic deformation can produce bonding at the interface. The use of a supersonic gas flow to accelerate such particles is known as Cold Spray deposition. The Cold Spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting material properties possible with polymeric compounds. In this work, a combined computational and experimental study a) simulated and optimized the nozzle flow conditions necessary to produce bonding in a polyethylene particle, b) developed and fabricated an experimental device, and c) explored temperature-pressure space across a range of substrate materials, resolving a material dependent ‘window of deposition’ where successful coatings form. Insights into bonding mechanisms are discussed, and paths forward proposed.
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Rom, Craig J. "Flow field and near nozzel fuel spray characterizations for a cold flowing vortex engine." 2006. http://catalog.hathitrust.org/api/volumes/oclc/70251820.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 2006.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 75-76).
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"Nozzle Design for Vacuum Aerosol Deposition of Nanostructured Coatings." Master's thesis, 2017. http://hdl.handle.net/2286/R.I.45486.
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abstract: Nanomaterials exhibit unique properties that are substantially different from their bulk counterparts. These unique properties have gained recognition and application for various fields and products including sensors, displays, photovoltaics, and energy storage devices. Aerosol Deposition (AD) is a relatively new method for depositing nanomaterials. AD utilizes a nozzle to accelerate the nanomaterial into a deposition chamber under near-vacuum conditions towards a substrate with which the nanomaterial collides and adheres. Traditional methods for designing nozzles at atmospheric conditions are not well suited for nozzle design for AD methods.
Computational Fluid Dynamics (CFD) software, ANSYS Fluent, is utilized to simulate two-phase flows consisting of a carrier gas (Helium) and silicon nanoparticles. The Cunningham Correction Factor is used to account for non-continuous effects at the relatively low pressures utilized in AD.
The nozzle, referred to herein as a boundary layer compensation (BLC) nozzle, comprises an area-ratio which is larger than traditionally designed nozzles to compensate for the thick boundary layer which forms within the viscosity-affected carrier gas flow. As a result, nanoparticles impact the substrate at velocities up to 300 times faster than the baseline nozzle.Dissertation/Thesis
Masters Thesis Electrical Engineering 2017
Book chapters on the topic "Cold spray nozzles"
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Jang, Sung Hwan, Sung Han Park, J. W. Han, Chang Hee Lee, and Hyung Jun Kim. "Factors of Nozzle Design Affecting on Supersonic Flow in Cold Spray Process." In Materials Science Forum, 1046–49. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-995-4.1046.
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Belbaki, Abderrahmane, and Yamina Mebdoua-Lahmar. "Influence of Diverging Section Length on the Supersonic Jet Delivered from Micro-nozzle: Application to Cold Spray Coating Process." In Lecture Notes in Mechanical Engineering, 465–73. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41468-3_39.
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Sakaki, K. "The influence of nozzle design in the cold spray process." In The Cold Spray Materials Deposition Process. CRC Press, 2007. http://dx.doi.org/10.1201/9781439824122.ch7.
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SAKAKI, K. "The influence of nozzle design in the cold spray process." In The Cold Spray Materials Deposition Process, 117–26. Elsevier, 2007. http://dx.doi.org/10.1533/9781845693787.2.117.
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Tlotleng, Monnamme, Esther T. Akinlabi, Mukul Shukla, and Sisa Pityana. "Application of Laser Assisted Cold Spraying Process for Materials Deposition." In Surface Engineering Techniques and Applications, 177–221. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-5141-8.ch006.
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The Laser-Assisted Cold Spraying (LACS) process is a hybrid technique that uses laser and cold spray mechanism to deposit solid powders on metal substrates. For bonding to occur, the particle velocities must be supersonic. The supersonic effects can be achieved by passing a highly compressed Nitrogen gas (˜30 bars) through de Laval supersonic nozzle. LACS is a surface coating technique that is desirable in rapid prototyping and manufacturing, particularly for biomedical applications. Current world research reveals that the capability of the LACS regarding the enhancement of surface properties of coating titanium alloys with hydroxyapatite will be essential for fabricating scaffolds for bone implants using Laser Engineered Net Shaping (LENS) technique. In this chapter, coatings of composite powders made of titanium and hydroxyapatite deposited on Ti-6Al-4V substrate by LACS technology are presented. These coatings were successfully characterised by means of X-Ray Diffraction (XRD) and optical microscopy for their phases, composition, and microstructure, respectively. The results of the produced LACS coatings compare well with those obtained with traditional thermal spray and cold spray techniques, respectively. In addition, the XRD results were found to be similar to the precursor powders, which indicated that no phase transformation occurred to HAP. Coatings comprising of other crystalline phases of HAP are less bio-integrable and fail quicker within the human body fluids environments.
Conference papers on the topic "Cold spray nozzles"
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Sakaki, K., N. Huruhashi, K. Tamaki, and Y. Shimizu. "Effect of Nozzle Geometry on Cold Spray Process." In ITSC2002, edited by C. C. Berndt and E. Lugscheider. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2002. http://dx.doi.org/10.31399/asm.cp.itsc2002p0385.
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Abstract Cold spray nozzles can have a significant impact on particle behavior and coating quality depending on their shape and size. This study investigates the influence of nozzle geometry on the cold spray process. Simulations show that particle velocities are highest at the outlet of de Laval type nozzles and that convergence pipe nozzles achieve the highest particle temperatures. Paper includes a German-language abstract.
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Jodoin, B., F. Raletz, and M. Vardelle. "Cold Spray Flow Modeling and Validation." In ITSC2005, edited by E. Lugscheider. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2005. http://dx.doi.org/10.31399/asm.cp.itsc2005p0165.
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Abstract In Cold Gas Dynamic Spraying the nozzle is a key part that must be optimized to maximize the injected particle acceleration and improve the coating quality. In this study an axi-symmetric two-dimensional mathematical model is presented and used to predict the flow inside a commercial cold spray nozzle and the particle velocity at the nozzle exit. Comparisons between the model results and the measurements made show that the model allows predicting accurately the particle velocity in the cold spray jet even in the presence of shock waves. The study shows that the particle exit velocity depends on the type of propellant gas used and the stagnation temperature and pressure. Following this work, the design of nozzles for specific applications using this mathematical model can be considered.
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Sharma, A. K., A. Vashishtha, D. Callaghan, C. Nolan, S. Bakshi, M. Kamaraj, and R. Raghavendra. "Particle Acceleration Through Coaxial Co-Flow Nozzles for Cold Spray Applications." In ITSC2022. DVS Media GmbH, 2022. http://dx.doi.org/10.31399/asm.cp.itsc2022p0676.
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Abstract The present study numerically investigates the effectiveness of co-flowing nozzles for cold spray applications. A convergent-divergent axi-symmetric nozzle system was simulated with high-pressure nitrogen flow. The particle acceleration is modelled by a two-way Lagrangian approach and validated with reference to experimental values reported in the literature. An annular co-flowing nozzle with circular central nozzle was simulated for nitrogen gas flow. The momentum preservation for central nozzle flow was observed, which results in higher particle speed for longer axial distance after nozzle exit. It is envisioned from the outcome that utilization of co-flow can lead to reduction in the divergent section length of cold spray central nozzles, which may ultimately help to address clogging issues for continuous operation. Co-flow operating at 3 MPa, same as with a central nozzle, can increase supersonic core length up to 23.8%.
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Gabor, Ted, Semih Akin, Jung-Ting Tsai, Seunghwan Jo, Feraas Al-Najjar, and Martin Byung-Guk Jun. "Numerical Studies on Cold Spray Particle Deposition Using a Rectangular Nozzle." In ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-85673.
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Abstract Cold spray additive manufacturing (CSAM) is an emerging technique for scalable and rapid deposition of thick metallic coatings on various substrates. Despite great promises, CSAM with no upper limit of coating thickness remains challenging due to the stochastic nature of cold spray (CS) deposition. In particular, using axisymmetric nozzles (i.e., circular supersonic nozzles) lead to a quasi-Gaussian shaped particle distribution on the target surface, which limits the CSAM due to the formation of triangular-shaped (i.e., peak/valley-shaped) coating morphology. Recently, rectangular cold spray nozzles have been applied to CS particle deposition, and found to be promising for CSAM owing to its more uniform particle distribution and wider spray beam. In these studies, however, process-structure properties of cold spray deposition with a rectangular nozzle have not been sufficiently elucidated. Practical expansion of rectangular nozzles in CSAM strictly depends on uncovering process-structure properties of CS deposition phenomenon. To this end, we investigate cold spray deposition of microscale particles using a rectangular nozzle through three-dimensional discrete-phase turbulent flow modeling. The numerical modeling results are experimentally justified using a dual disc anemometer setup. The influence of operating gas conditions on critical particle deposition parameters is studied. An experimental case study of cold spray particle deposition on a polymer (ABS) substrate is also conducted to show the potential of rectangular nozzle in cold-spray based polymer metallization. The results suggest that cold spraying using a rectangular nozzle is beneficial for a more uniform, compact, and higher precision particle distribution on the target surface.
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Zavalan, Florentina-Luiza, and Aldo Rona. "Parametric Redesign of a Convergent-Divergent Cold Spray Nozzle." In ITSC2021, edited by F. Azarmi, X. Chen, J. Cizek, C. Cojocaru, B. Jodoin, H. Koivuluoto, Y. C. Lau, et al. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.itsc2021p0221.
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Abstract The generation of a high velocity carrier gas flow for cold metal particle applications is addressed; with specific focus on titanium cold spraying. The high hardness of this material makes cold spraying titanium difficult to achieve by industry standard nozzles. The redesign of a commercial conical convergent-divergent cold spray nozzle is achieved by the application of aerospace design codes; based on the Method of Characteristics; towards producing a more isentropic expansion by contouring the nozzle walls. Steady threedimensional RANS SST k-ω simulations of nitrogen are coupled two-way to particle parcel tracking in the Lagrangian frame of reference. The new contoured nozzle is found to produce higher particle velocities with greater radial spread; when operated at the same conditions/cost of operation as the commercial nozzle. These numerical results have shown the potential for extending cold spray to high density and low ductility particles by relatively minor rig modifications; through an effective synergy between gas dynamics and material science.
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Karthikeyan, J., and C. M. Kay. "Cold Spray Technology: An Industrial Perspective." In ITSC2003, edited by Basil R. Marple and Christian Moreau. ASM International, 2003. http://dx.doi.org/10.31399/asm.cp.itsc2003p0117.
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Abstract ASB Industries is involved in taking the cold spray technology from research lab into industrial applications. Cold spray programs include building a human engineered spray system, design and development of nozzles and guns capable of reliable and reproducible operation for long duration spray, process optimization for producing quality coatings at reasonable deposition efficiency and deposition rate values and preparation and characterization of coatings of industrially relevant materials. These research activities have resulted in the development of a patented ‘Advanced Cold Spray System’ with enhanced features and performance characteristics. ASB is involved in a number R&D programs to develop engineered coatings for specific customers, and a few of these applications are in various stages of commercial adaptation.
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Ho, Son H., and Muhammad M. Rahman. "Zero Boil-Off Cryogenic Liquid Hydrogen Storage Tank With Axial Cold-Spray System." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15341.
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This paper presents a steady-state analysis of fluid flow and heat transfer in a zero boil-off cryogenic storage tank for liquid hydrogen. The system includes a tank with cylindrical wall and oblate spheroidal top and bottom, and a cold-spray nozzle head whose face is set perpendicular to the axis of the tank. The nozzle head has many nozzles on its front face. The cold fluid cooled by an external cooling system enters the inlet opening at the top of the tank, follows an axial supply tube to the nozzle head and exits through the nozzles into the bulk fluid inside the tank heated by heat leak from the surroundings. The displaced fluid exits the tank through an annular outlet opening (also at the top of the tank and concentric with the inlet opening) then goes back to the external cooling system. This study considers the transport phenomena in the storage tank only with prescribed fluid flow velocity and temperature at the inlet to represent the external cooling system.
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Dykhuizen, R. C., and R. A. Neiser. "Optimizing the Cold Spray Process." In ITSC2003, edited by Basil R. Marple and Christian Moreau. ASM International, 2003. http://dx.doi.org/10.31399/asm.cp.itsc2003p0019.
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Abstract Cold spray is a new coating technique that does not involve significant heating of the sprayed material. Thus, it can be used to deposit thermally sensitive materials. Due to the fact that complex processes, such as combustion and ionization of the process gas are avoided, cold spray becomes very amenable to analytical modeling. To deposit with high efficiency, and to yield low porosity and high bond strength coatings, developers of the cold spray process have tried to maximize the impact velocity. Earlier studies have clearly shown that low molecular weight gases, long nozzles, high gas temperatures and pressures yield high impact velocities. Use of smaller particles of low-density materials also can increase the impact velocity. However, there is a limit to the gains that can be obtained with smaller particles due to the deceleration of the particles in the near stagnant region in front of the substrate. This study analytically estimates the optimum particle size in terms of other input values. To investigate the conventional wisdom that a higher impact velocity results in a better coating, a small experimental program was initiated. Experimental results clearly demonstrate the advantages of high impact velocities. These results confirm that the deposition efficiency, bond strength, porosity and surface roughness are all improved as the impact velocity increases. Limited experimental data also demonstrate that some coating properties depend not only on the particle impact velocity but also the particle impact temperature. The bond strength showed a dramatic increase when the particle impact temperature was increased. Small improvements were also observed for the deposition efficiency and the porosity.
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Blose, R. E., T. J. Roemer, R. T. Nichols, A. J. Mayer, and D. E. Beatty. "Automated Cold Spray System: Description of Equipment and Performance Data." In ITSC2005, edited by E. Lugscheider. Verlag für Schweißen und verwandte Verfahren DVS-Verlag GmbH, 2005. http://dx.doi.org/10.31399/asm.cp.itsc2005p0058.
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Abstract Cold spray is adding another dimension to thermal spray coating processes with numerous applications that have yet to be realized. Current activities in the field of Cold Spray are rapidly moving from R&D to commercial applications in industry. To successfully commercialize the technology, cost effective, low maintenance, highly reliable, easy to operate equipment must be available and supported that is designed so that the spray processes can be controlled and repeated. With the growth of this technology there will be a demand for laboratory systems to perform applications research and development as well as high volume production machines for specific industrial applications. The recent focus of Cold Spray equipment development has been to perfect nozzles and gun assemblies, gas heaters, gas flow, powder feed, and process control. This paper describes the automated equipment that is available in the market today and presents advances in nozzle and gas heater performance as well as development of a laboratory powder feeder. This equipment will serve as the baseline for equipment that will soon be installed in industry for commercial production applications.
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Farvardin, E., O. Stier, V. Luthen, and A. Dolatabadi. "Effect of Using Liquid Feedstock in a High Pressure Cold Spray Nozzle." In ITSC2010, edited by B. R. Marple, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and G. Montavon. DVS Media GmbH, 2010. http://dx.doi.org/10.31399/asm.cp.itsc2010p0625.
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Abstract This study investigates the effect of water injection in the high pressure chamber of a cold spray nozzle. A de Laval nozzle geometry with constant back pressure and temperature is modeled numerically using Reynolds Stress Model coupled equations. Water spray with a droplet size of 10 – 100 μm is modeled using both uniform and Rosin-Rammler size distributions. The two-phase flow of gas-liquid is modeled using an unsteady discrete phase mass source with two-way coupling with the main gas flow. Upon injection, the droplets in the water spray evaporate while travelling through the nozzle due to momentum and energy exchange with the gas flow. The evaporation behavior in presence of water content is modeled and a correlation between the initial diameter and the diameter just before the throat is obtained. As a result, the proper droplet size distribution with a fully evaporative spray can be used as a carrier of nano-particles in cold spray nozzles. Having the results, guide us to substitute the un-evaporated part of the droplet with an equal diameter agglomerate of nano particles and find a minimum fraction of nano particles suspended in the liquid which guarantees fully evaporative liquid spray injection.
Reports on the topic "Cold spray nozzles"
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Madrzykowski, Daniel, and Nicholas Dow. Residential Flashover Prevention with Reduced Water Flow: Phase 1. UL Firefighter Safety Research Institute, April 2020. http://dx.doi.org/10.54206/102376/jegf7178.
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This study was designed to be an initial step to investigate the potential of low flow nozzles as part of a retrofit flashover prevention system in residential homes with limited water supplies. Not all homes have water supplies that can meet the needs of a residential sprinkler system. Current alter- natives, such as including a supplemental tank and pump, increase the cost of the system. These homes could benefit from an effective fire safety system with lower water supply requirements. The experiments in this study were conducted in a steel test structure which consisted of a fire room attached to a hallway in an L-shaped configuration. Three types of experiments were conducted to evaluate nozzles at different flow rates and under different fire conditions. The performance of the nozzles was compared to the performance of a commercially available residential sprinkler. The first set of experiments measured the distribution of the water spray from each of the nozzles and the sprinkler. The water spray measurements were made without the presence of a fire. The other two sets of experiments were fire experiments. The first set of fire experiments were designed to measure the ability of a water spray to cool a hot gas layer generated by a gas burner fire. The fire source was a propane burner which provided a steady and repeatable flow of heat into the test structure. Two water spray locations were examined, in the fire room and in the middle of the hallway. In each position, the burner was shielded from the water spray. The results showed that for equivalent conditions, the nozzle provided greater gas cooling than the sprinkler. The tests were conducted with a fire size of approximately 110 kW, and water flow rates in the range of 11 lpm (3 gpm) and 19 lpm (5 gpm). The second set of fire experiments used an upholstered sofa as the initial source of the fire with the water spray located in the same room. As a result of the compartment size and water spray distribution, the nozzle flowing water at 23 lpm (6 gpm) provided more effective suppression of the fire than the sprinkler flowing 34 lpm (9 gpm) did. The nozzle was similarly effective with the ignition location moved 1.0 m (3.2 ft) further away. However, the nozzle failed to suppress the fire with a reduced water flow rate of 11 lpm (3 gpm). The results of this limited study demonstrate the potential of low flow nozzles, directly flowing water on to the fuel surface, with the goal of preventing flashover. Additional research is needed to examine larger room sizes, fully furnished rooms, and shielded fires to determine the feasibility of a reduced water flow flashover prevention system.
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Dow, Nick, and Daniel Madrzykowski. Residential Flashover Prevention with Reduced Water Flow: Phase 2. UL's Fire Safety Research Institute, November 2021. http://dx.doi.org/10.54206/102376/nuzj8120.
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The purpose of this study was to investigate the feasibility of a residential flashover prevention system with reduced water flow requirements relative to a residential sprinkler system designed to meet NFPA 13D requirements. The flashover prevention system would be designed for retrofit applications where water supplies are limited. In addition to examining the water spray’s impact on fire growth, this study utilized thermal tenability criteria as defined in UL 199, Standard for Automatic Sprinklers for Fire-Protection Service. The strategy investigated was to use full cone spray nozzles that would discharge water low in the fire room and directly onto burning surfaces of the contents in the room. Where as current sprinkler design discharges water in a manner that cools the hot gas layer, wets the walls and wets the surface of the contents in the fire room. A series of eight full-scale, compartment fire experiments with residential furnishings were conducted with low flow nozzles. While the 23 lpm (6 gpm) of water was the same between experiments, the discharge density or water flux around the area of ignition varied between 0.3 mm/min (0.008 gpm/ft2) and 1.8 mm/min (0.044 gpm/ft2). Three of the experiments prevented flashover. Five of the experiments resulted in the regrowth of the fire while the water was flowing. Regrowth of the fire led to untenable conditions, per UL 199 criteria, in the fire room. At approximately the same time as the untenability criteria were reached, the second sprinkler in the hallway activated. In a completed system, the activation of the second sprinkler would reduce the water flow to the fire room, which would potentially lead to flashover. The variations in the burning behavior of the sofa resulted in shielded fires which led to the loss of effectiveness of the reduced flow solid cone water sprays. As a result of these variations, a correlation between discharge density at the area of ignition and fire suppression performance could not be determined given the limited number of experiments. An additional experiment using an NFPA 13D sprinkler system, flowing 30 lpm (8 gpm), demonstrated more effective suppression than any of the experiments with a nozzle. The success of the sprinkler compared with the unreliable suppression performance of the lower flow nozzles supports the minimum discharge density requirements of 2 mm/min (0.05 gpm/ft2) from NFPA 13D. The low flow nozzle system tested in this study reliably delayed fire growth, but would not reliably prevent flashover.