A new model for puffing and micro-explosion of single titanium(IV) isopropoxide/p-xylene precursor solution droplets
In flame spray pyrolysis, the precursor solution droplet undergoes heating and evaporation, followed by gas phase combustion and generation of nanoparticles. Depending on the precursor solution, the precursor/solvent droplet may experience puffing and micro-explosion. A new one-dimensional model is...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
March 2023
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| In: |
International journal of heat and mass transfer
Year: 2023, Volume: 202, Pages: 1-11 |
| ISSN: | 1879-2189 |
| DOI: | 10.1016/j.ijheatmasstransfer.2022.123647 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.ijheatmasstransfer.2022.123647 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0017931022011164 
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| Author Notes: | Praveen Narasu, Eva Gutheil |
| Summary: | In flame spray pyrolysis, the precursor solution droplet undergoes heating and evaporation, followed by gas phase combustion and generation of nanoparticles. Depending on the precursor solution, the precursor/solvent droplet may experience puffing and micro-explosion. A new one-dimensional model is developed to describe these processes in the spherically symmetric droplet interior with emphasis on the puffing and the micro-explosion. After the initial droplet heating, the preferential evaporation of the higher volatile component causes the accumulation of the lower volatile precursor at the droplet surface and thus forms a liquid shell that hinders the evaporation process. In the droplet interior away from the liquid shell, the higher volatile component accumulates and when the temperature reaches the boiling point of that liquid, puffing occurs. If the pressure inside the droplet exceeds the ambient pressure, the droplet undergoes micro-explosion. The present study concerns single precursor/solvent droplets of titanium(IV) isopropoxide (TTIP) in p-xylene at room temperature in hot convective air at atmospheric pressure. A parameter study is performed to show the dependence of the puffing and the micro-explosion on the initial precursor loading, the initial droplet size, the ambient gas temperature, and the relative velocity between the droplet and the ambience. There are situations where micro-explosion follows the puffing or puffing repeats until the end of the droplet lifetime with no micro-explosion. This is the first model to successfully describe the puffing in precursor solution droplets and the micro-explosion which may follow the puffing. |
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| Item Description: | Online verfügbar am 26. November 2022 Gesehen am 13.03.2023 |
| Physical Description: | Online Resource |
| ISSN: | 1879-2189 |
| DOI: | 10.1016/j.ijheatmasstransfer.2022.123647 |