The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection
In this study, experiments and numeric studies were conducted to analyze the causes of abnormal behavior in temperature, heat flux, and combustion efficiency that occurred before a compartment fire was converted to the under-ventilated condition. The fire experiments were performed using a 1/4 reduc...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-11-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/12/23/12278 |
| _version_ | 1797463617290895360 |
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| author | Hong-Seok Yun Sun-Yeo Mun Cheol-Hong Hwang |
| author_facet | Hong-Seok Yun Sun-Yeo Mun Cheol-Hong Hwang |
| author_sort | Hong-Seok Yun |
| collection | DOAJ |
| description | In this study, experiments and numeric studies were conducted to analyze the causes of abnormal behavior in temperature, heat flux, and combustion efficiency that occurred before a compartment fire was converted to the under-ventilated condition. The fire experiments were performed using a 1/4 reduced-scale ISO 9705 compartment and propane fuel. Considering that the occurrence and termination of abnormal behavior are related to ventilation conditions, vertical openings of various shapes designed to have the identical ventilation factor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.52</mn><mi mathvariant="normal">A</mi><msqrt><mi mathvariant="normal">h</mi></msqrt></mrow></semantics></math></inline-formula>) were used. As a result, an abnormal phenomenon was observed in which the measured heat release rate did not increase despite the increase in the fuel flow rate under the over-ventilation condition in all opening shapes. Due to this phenomenon, the combustion efficiency was reduced to 70% regardless of the opening shape. In order to understand these abnormal behaviors and to analyze the causes of their occurrence, the temperature and chemical species concentrations of the opening discharge flow were measured. The results indicated that the abnormal behavior of thermal physical quantities, HRR, and combustion efficiency occurred because fuel that was not burned inside the compartment did not reach the lower combustion limit even outside the compartment and was discharged. |
| first_indexed | 2024-03-09T17:53:18Z |
| format | Article |
| id | doaj.art-6c6fe983543a4e1dbe6e33427b1b62fc |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-09T17:53:18Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
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| series | Applied Sciences |
| spelling | doaj.art-6c6fe983543a4e1dbe6e33427b1b62fc2023-11-24T10:33:54ZengMDPI AGApplied Sciences2076-34172022-11-0112231227810.3390/app122312278The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame EjectionHong-Seok Yun0Sun-Yeo Mun1Cheol-Hong Hwang2Department of Fire and Disaster Prevention, Daejeon University, Daehak-ro 62, Daejeon 34520, Republic of KoreaDepartment of Disaster Prevention, Graduate School, Daejeon University, Daehak-ro 62, Daejeon 34520, Republic of KoreaDepartment of Fire and Disaster Prevention, Daejeon University, Daehak-ro 62, Daejeon 34520, Republic of KoreaIn this study, experiments and numeric studies were conducted to analyze the causes of abnormal behavior in temperature, heat flux, and combustion efficiency that occurred before a compartment fire was converted to the under-ventilated condition. The fire experiments were performed using a 1/4 reduced-scale ISO 9705 compartment and propane fuel. Considering that the occurrence and termination of abnormal behavior are related to ventilation conditions, vertical openings of various shapes designed to have the identical ventilation factor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.52</mn><mi mathvariant="normal">A</mi><msqrt><mi mathvariant="normal">h</mi></msqrt></mrow></semantics></math></inline-formula>) were used. As a result, an abnormal phenomenon was observed in which the measured heat release rate did not increase despite the increase in the fuel flow rate under the over-ventilation condition in all opening shapes. Due to this phenomenon, the combustion efficiency was reduced to 70% regardless of the opening shape. In order to understand these abnormal behaviors and to analyze the causes of their occurrence, the temperature and chemical species concentrations of the opening discharge flow were measured. The results indicated that the abnormal behavior of thermal physical quantities, HRR, and combustion efficiency occurred because fuel that was not burned inside the compartment did not reach the lower combustion limit even outside the compartment and was discharged.https://www.mdpi.com/2076-3417/12/23/12278compartment fireventilation conditioncombustion efficiencyglobal equivalence ratiofire behavior |
| spellingShingle | Hong-Seok Yun Sun-Yeo Mun Cheol-Hong Hwang The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection Applied Sciences compartment fire ventilation condition combustion efficiency global equivalence ratio fire behavior |
| title | The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection |
| title_full | The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection |
| title_fullStr | The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection |
| title_full_unstemmed | The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection |
| title_short | The Sinkhole Phenomenon—Changes in Compartment Fire Characteristics Due to Incomplete Combustion before Flame Ejection |
| title_sort | sinkhole phenomenon changes in compartment fire characteristics due to incomplete combustion before flame ejection |
| topic | compartment fire ventilation condition combustion efficiency global equivalence ratio fire behavior |
| url | https://www.mdpi.com/2076-3417/12/23/12278 |
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