Smoldering combustion and blow-off in incense sticks (Effect of wind directions)
The smoldering spread and extinction behavior are significantly impacted by both wind velocity and angle. However, this combined effect has not been extensively quantified. This study investigates the influence of the wind angle, ranging from θ0 = 0° (concurrent smoldering spread) to θ0 = 180° (oppo...
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| Language: | English |
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The Japan Society of Mechanical Engineers
2025-05-01
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| Series: | Journal of Thermal Science and Technology |
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| Online Access: | https://www.jstage.jst.go.jp/article/jtst/20/1/20_24-00387/_pdf/-char/en |
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| author | Pichayaporn VIRIYA-AMORNKIJ Kazunori KUWANA Yunzhu QIN Xinyan HUANG |
| author_facet | Pichayaporn VIRIYA-AMORNKIJ Kazunori KUWANA Yunzhu QIN Xinyan HUANG |
| author_sort | Pichayaporn VIRIYA-AMORNKIJ |
| collection | DOAJ |
| description | The smoldering spread and extinction behavior are significantly impacted by both wind velocity and angle. However, this combined effect has not been extensively quantified. This study investigates the influence of the wind angle, ranging from θ0 = 0° (concurrent smoldering spread) to θ0 = 180° (opposed smoldering spread), which is defined as the angle between the directions of the forced airflow and the reaction propagation, on blow-off limit and smoldering spread rate of 2.5 mm incense sticks using a rotating apparatus. The experimental results indicate an increase in smoldering rates and blow-off wind velocity as θ0 decreases. The maximum average smoldering rate is about 2.5 cm/min at θ0 = 0°, while it is less than 1 cm/min at θ0 = 180°. The blow-off wind velocity is 15 m/s at θ0 = 0° and 5 m/s at θ0 = 180°. The blow-off limit was discussed based on Damköhler number (Da). A simplified heat transfer analysis, coupled with computational fluid dynamics simulation, was used to calculate the smoldering rate. The simple model captures the experimental trend of the increasing smoldering rate at low wind velocity. A higher smoldering temperature results in a higher smoldering rate. Additionally, the higher smoldering rate observed at θ0 = 0° was reproduced, emphasizing the significant role of heat transfer. To maintain a steady smoldering rate, all the heat produced by the reactions must be removed, which occurs most efficiently at θ0 = 0°, leading to the highest smoldering rate. |
| format | Article |
| id | doaj-art-2057ec963f644c6ab78dcdcf1932c96e |
| institution | Kabale University |
| issn | 1880-5566 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Thermal Science and Technology |
| spelling | doaj-art-2057ec963f644c6ab78dcdcf1932c96e2025-08-20T03:29:35ZengThe Japan Society of Mechanical EngineersJournal of Thermal Science and Technology1880-55662025-05-0120124-0038724-0038710.1299/jtst.24-00387jtstSmoldering combustion and blow-off in incense sticks (Effect of wind directions)Pichayaporn VIRIYA-AMORNKIJ0Kazunori KUWANA1Yunzhu QIN2Xinyan HUANG3Department of Global Fire Science and Technology, Tokyo University of ScienceDepartment of Global Fire Science and Technology, Tokyo University of ScienceDepartment of Building Environment and Energy Engineering, The Hong Kong Polytechnic UniversityDepartment of Building Environment and Energy Engineering, The Hong Kong Polytechnic UniversityThe smoldering spread and extinction behavior are significantly impacted by both wind velocity and angle. However, this combined effect has not been extensively quantified. This study investigates the influence of the wind angle, ranging from θ0 = 0° (concurrent smoldering spread) to θ0 = 180° (opposed smoldering spread), which is defined as the angle between the directions of the forced airflow and the reaction propagation, on blow-off limit and smoldering spread rate of 2.5 mm incense sticks using a rotating apparatus. The experimental results indicate an increase in smoldering rates and blow-off wind velocity as θ0 decreases. The maximum average smoldering rate is about 2.5 cm/min at θ0 = 0°, while it is less than 1 cm/min at θ0 = 180°. The blow-off wind velocity is 15 m/s at θ0 = 0° and 5 m/s at θ0 = 180°. The blow-off limit was discussed based on Damköhler number (Da). A simplified heat transfer analysis, coupled with computational fluid dynamics simulation, was used to calculate the smoldering rate. The simple model captures the experimental trend of the increasing smoldering rate at low wind velocity. A higher smoldering temperature results in a higher smoldering rate. Additionally, the higher smoldering rate observed at θ0 = 0° was reproduced, emphasizing the significant role of heat transfer. To maintain a steady smoldering rate, all the heat produced by the reactions must be removed, which occurs most efficiently at θ0 = 0°, leading to the highest smoldering rate.https://www.jstage.jst.go.jp/article/jtst/20/1/20_24-00387/_pdf/-char/ensmoldering rateblow-off limitwind angleincense sticksheat transfer analysis |
| spellingShingle | Pichayaporn VIRIYA-AMORNKIJ Kazunori KUWANA Yunzhu QIN Xinyan HUANG Smoldering combustion and blow-off in incense sticks (Effect of wind directions) Journal of Thermal Science and Technology smoldering rate blow-off limit wind angle incense sticks heat transfer analysis |
| title | Smoldering combustion and blow-off in incense sticks (Effect of wind directions) |
| title_full | Smoldering combustion and blow-off in incense sticks (Effect of wind directions) |
| title_fullStr | Smoldering combustion and blow-off in incense sticks (Effect of wind directions) |
| title_full_unstemmed | Smoldering combustion and blow-off in incense sticks (Effect of wind directions) |
| title_short | Smoldering combustion and blow-off in incense sticks (Effect of wind directions) |
| title_sort | smoldering combustion and blow off in incense sticks effect of wind directions |
| topic | smoldering rate blow-off limit wind angle incense sticks heat transfer analysis |
| url | https://www.jstage.jst.go.jp/article/jtst/20/1/20_24-00387/_pdf/-char/en |
| work_keys_str_mv | AT pichayapornviriyaamornkij smolderingcombustionandblowoffinincensestickseffectofwinddirections AT kazunorikuwana smolderingcombustionandblowoffinincensestickseffectofwinddirections AT yunzhuqin smolderingcombustionandblowoffinincensestickseffectofwinddirections AT xinyanhuang smolderingcombustionandblowoffinincensestickseffectofwinddirections |