Analysis of heat-not-burn (HNB) smoking system technologies
A conceptual model was proposed to evaluate the time evolution of the air velocity field, as well as the temperature evolution, in a porous medium, such as the tobacco bed placed in a study volume, and the content of the various substances contained in the tobacco product such as water, glycerin and...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-07-01
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| Series: | International Journal of Thermofluids |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666202725002666 |
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| Summary: | A conceptual model was proposed to evaluate the time evolution of the air velocity field, as well as the temperature evolution, in a porous medium, such as the tobacco bed placed in a study volume, and the content of the various substances contained in the tobacco product such as water, glycerin and nicotine. It was found that the time step during which the momentum changes is at least two orders of magnitude smaller than the time step for temperature and mass changes, leading to the decision to decouple the resolution of the balances. The study volume is a cylinder with a diameter of 10 mm and a height of 17 mm, containing tobacco strands no longer than 5 mm and with a cross-section of 1.3 mm by 0.2 mm, to which heat is applied through the outer surface. Operating conditions were analyzed based on the compactness of the tobacco mass in the study volume (300 mg, 400 mg and 600 mg), the nominal temperature of the outer surface of the study volume (150 °C, 200 °C and 220 °C) and the time required to reach this temperature during the heating period (40 s or 50 s). The pressure difference applied to the porous bed was estimated using a model that was experimentally verified, with a flow rate of 17.5 ml/s applied during each puff in all cases. It was experimentally verified that the developed model satisfactorily reproduced the time evolution of the temperature during the heating process. In cases of high compactness, greater uniformity of the temperature field and higher temperatures in the tobacco mass were observed compared to cases of low compactness. In cases of low compactness, a central zone was identified where substances such as nicotine would not be consumed, while at the wall it would be consumed in a puff. In the case of higher compactness, a more uniform behavior was achieved, with durations ranging from 4 to 37 puffs. It was identified that energy consumption would reach a minimum depending on the load for a given nominal temperature. The consumption of water contained in the tobacco influences how the temperature changes over time. It was observed that the temperature distributions seem to scale with the diameter of the oven and that, as the diameter increases, a larger region appears where the temperature seems uniform and the temperature at the center becomes higher. |
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| ISSN: | 2666-2027 |