Heat transfer analysis in pulsed pressure mass transport.
| dc.contributor.author | Mohamed, Salma Hamdy Radwan | |
| dc.date.accessioned | 2024-05-29T02:03:43Z | |
| dc.date.available | 2024-05-29T02:03:43Z | |
| dc.date.issued | 2024 | |
| dc.description.abstract | PPMOCVD is a technique for depositing thin-film coatings on a heated substrate. It includes controlled pulses of precursor solution injected through an ultrasonic nozzle into an evacuated low-pressure reactor. Heat and mass transfer are crucial in PPMOCVD and significantly influence deposition. Temperature profiles govern heat transfer, impacting chemical reactions and material deposition. Mass transfer is driven by solvent injection, which determines the quality and composition of the deposited material. The primary aim of this research is to extensively explore various aspects related to the PPMOCVD process, aiming to enhance understanding and optimize system performance. Critical focus areas include adapting and validating a resistively heated wire technique for use as the heated substrate, analyzing the heat transfer implications of different solvent injections, and assessing the influence of introducing a physical barrier "shield," on the heat transfer process. The research was initiated by adapting halogen light bulb technology and filament to develop a precise temperature measurement method. This method was employed to assess wire temperature uniformity under resistive heating using a comprehensive COMSOL model. Additionally, experiments in heated liquid baths facilitated reliable temperature measurements and the determination of the temperature coefficient (α) for halogen light bulb filaments. Further investigation delved into heat transfer dynamics within the PPMOCVD system. Initial measurements were taken to determine the wire temperature range where radiation appeared as the dominant heat transfer mode, a crucial factor in determining wire temperature before pulsing and ensuring measurement consistency. The pulsed heat transfer coefficient (ℎ𝑝) was the focus point, with detailed calculations and analysis conducted in response to alterations in PPMOCVD parameters, including solvent volume, pulsing duration, and resistively heated wire temperature. Another experiment was conducted to assess the changes in the heat transfer coefficient by varying the injected solvent, focusing on toluene, butanol, and isopropanol due to their favorable vaporization properties. The experimental findings provided valuable insights into various aspects of the PPMOCVD process. Firstly, the investigation into wire temperature ranges elucidated the dominance of heat conduction as the primary mode of heat transfer below 250 °C, shifting to radiation as the dominant mode beyond this threshold. This understanding is crucial for optimizing heat transfer efficiency within the system. Additionally, the experiments assessing changes in the pulsed heat transfer coefficient unveiled significant impacts of altering PPMOCVD parameters. Longer pulsing times and increased solvent volume were associated with reduced heat transfer coefficients, highlighting the importance of parameter optimization for efficient heat transport. The statistical analyses confirmed the significance of pulsing time, injected volume, and mean reactor pressure on the pulsed heat transfer coefficient, providing a comprehensive understanding of the factors influencing heat transfer efficiency in the PPMOCVD system. Furthermore, the investigation into different solvents revealed isopropanol as the most effective in enhancing heat transfer efficiency, emphasizing the role of solvent choice in optimizing system performance. These findings collectively contribute to a deeper understanding of heat transfer dynamics in PPMOCVD and provide practical insights for enhancing deposition processes in materials science and advanced electronics manufacturing. Overall, this research contributes to a deeper understanding of heat and mass transfer in the PPMOCVD system and provides practical insights for optimizing this crucial technology in materials science, vacuum, and advanced electronics manufacturing. | |
| dc.identifier.uri | https://hdl.handle.net/10092/107120 | |
| dc.identifier.uri | https://doi.org/10.26021/15368 | |
| dc.language | English | |
| dc.language.iso | en | |
| dc.rights | All Right Reserved | |
| dc.rights.uri | https://canterbury.libguides.com/rights/theses | |
| dc.title | Heat transfer analysis in pulsed pressure mass transport. | |
| dc.type | Theses / Dissertations | |
| thesis.degree.discipline | Mechanical Engineering | |
| thesis.degree.grantor | University of Canterbury | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy | |
| uc.college | Faculty of Engineering |
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