Diagnostic Methods and Parameters to Characterize Droplets and Particles in Suspension Plasma Spray

Suspension plasma spray (SPS) is an emerging coating process for making surfaces with superior properties. In the SPS process, ceramic particles are mixed with water or ethanol to form a suspension. A plasma torch provides the heat and momentum to evaporate liquid phase of the injected suspension, melt the coating particles, propel the in-flight particles toward a substrate, and eventually form a coating layer. However, the SPS process relies strongly on the coupon test and trials to find optimum spray conditions for plasma, suspension injection, and substrate location. At the end, an optimum spray condition set in a spray booth may not reproduce the same coating result in other booths. An effective control over the spray process improves the reproducibility of the spray conditions and consequently coating structures. Therefore, monitoring systems are employed to better understand and control the required spray condition. The monitoring included accessing state of droplets after the atomization of suspension and state of in-flight particles near the substrate. For further development of the SPS process, the suspension can be injected by an effervescent atomizer. This research aims to contribute in further improving the process and developing the diagnostic tools in SPS. For a further improvement of the SPS process, an effervescent atomizer was investigated as an alternative way instead of the current methods of injection of the suspension in the plasma jet. Performance of the effervescent atomizer was investigated at room temperature by phase Doppler particle anemometry (PDPA). Size of droplets and shape of the atomized spray in a crossflow configuration was almost independent of the suspension concentration. Size of droplets depends on the atomization at the exit of the orifice and the breakup in the crossflow. Velocity of droplets at downstream is the velocity of the crossflow. It was found that the shape of spray was conserved in the crossflow and relatively smaller droplets were enveloped by the larger droplets. As a contribution to adapt a diagnostic system for SPS, a two-color pyrometer was modified and investigated to measure temperature of in-flight particles. The in-flight particles are released after evaporation of the liquid phase of suspension droplets. A high cooling rate of the in-flight particles in terms of distance from the torch and radiation of plasma are main challenges for temperature measurement. To remove these limitations, the temperature was measured by a single-point measurement system based on thermal emission which equipped by readjusted bandpass filtering. The result of online temperature and velocity measurement was in a good agreement with the offline validation by collecting the splats and analyzing the samples. Moreover, the measurement condition has an impact on temperature, and the impact can be minimized by elimination of the stray radiation. As a fundamental research work to develop a diagnostic system for SPS, a light diffraction (LD) system was adapted and investigated to measure size of in-flight particles. Refraction of the laser in the measurement volume and radiation from plasma were two main challenges of the size measurement. A shield of an optimized aperture was employed to control the condition of measurement volume. By applying a narrow bandpass filter at a right wavelength and selecting a right angle to collect the scattered signal from the in-flight particles, the size of particles was measured. A good agreement between the result of online measurements under the plasma condition and studying the feedstock particles in the wet cell unit in the room condition validated the size measurement

Aeronautical engineering: A continuing bibliography with indexes (supplement 257)

This bibliography lists 560 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1990. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Environmental Impact of Aviation and Sustainable Solutions

Environmental Impact of Aviation and Sustainable Solutions is a compilation of review and research articles in the broad field of aviation and the environment. Over three sections and thirteen chapters, this book covers topics such as aircraft design and materials, combustor modeling, atomization, airport pollution, sonic boom and street noise pollution, emission mitigation strategies, and environmentally friendly contributions from a Russian aviation pioneer. This volume is a useful reference for both researchers and students interested in learning about various aspects of aviation and the environmen

Aeronautical engineering: A continuing bibliography with indexes (supplement 272)

This bibliography lists 719 reports, articles, and other documents introduced into the NASA scientific and technical information system in November, 1991. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Fifth International Microgravity Combustion Workshop

This conference proceedings document is a compilation of 120 papers presented orally or as poster displays to the Fifth International Microgravity Combustion Workshop held in Cleveland, Ohio on May 18-20, 1999. The purpose of the workshop is to present and exchange research results from theoretical and experimental work in combustion science using the reduced-gravity environment as a research tool. The results are contributed by researchers funded by NASA throughout the United States at universities, industry and government research agencies, and by researchers from at least eight international partner countries that are also participating in the microgravity combustion science research discipline. These research results are intended for use by public and private sector organizations for academic purposes, for the development of technologies needed for the Human Exploration and Development of Space, and to improve Earth-bound combustion and fire-safety related technologies

Aeronautical engineering: A cumulative index to a continuing bibliography (supplement 274)

This publication is a cumulative index to the abstracts contained in supplements 262 through 273 of Aeronautical Engineering: A Continuing Bibliography. The bibliographic series is compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). Seven indexes are included: subject, personal author, corporate source, foreign technology, contract number, report number, and accession number

Aeronautical engineering: A continuing bibliography with indexes (supplement 231)

This bibliography lists 469 reports, articles, and other documents introduced into the NASA scientific and technical information system in September, 1988

Bibliography of Lewis Research Center technical publications announced in 1993

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1993. All the publications were announced in the 1993 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Aeronautical Engineering: A continuing bibliography with indexes (supplement 182)

This bibliography lists 475 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1984

Argonne National Laboratory Reports

This sixth symposium covers process control processes and issues involved in the conversion of fossil fuels into synthetic fuels