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DC FieldValueLanguage
dc.contributorDepartment of Building Services Engineeringen_US
dc.contributor.advisorChow, W. K. (BSE)-
dc.creatorWang, Qi-
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleA numerical study on performance of smoke exhaust systems in large underground spaceen_US
dcterms.abstractFire accidents have caused serious damage in many places, especially in large-underground space. Performance of smoke exhaust systems installed at a space should be considered. Many experiments overlooked smoke exhaust systems of large underground halls. The project aims to compare two different smoke exhaust systems and find out which system is more appropriate for large-underground space. It was justified that static smoke extract system was better to smoke control in a large underground hall when the fire was large. In respect to a small fire, dynamic smoke extract system showed higher efficiency. The results were justified by Fire Dynamic Simulator version 6.7.0 (FDS) which is applied to design smoke exhaust system under different conditions, like fire size, over-ground wind effect, the height of underground space. A station in the underground with a large volume space was as a case example for the study on the performance of different smoke exhaust systems. The heat release rate of burning fire is constant, which called steady fire. As the buoyancy is the driving force in natural venting system and the buoyancy is related to the fire size, three groups with 5MW, 20MW, 50MW heat release rate respectively were used to analyse the differences in the smoke layer interface height, smoke temperature rise when the fire resisting shutters were closed. Each group has four scenarios with different smoke exhaust systems from no openings to two systems in combination were analysed. Besides the heat release rate, the activation time of opening vents and make-up air also have impacts on the function of smoke management systems. Some relevant fire safety standards and design codes about smoke management systems were studied. Recommendations of design and choose a smoke management system also discussed. By comparing the results of the theoretical analysis, experiments and fire dynamic simulations, the applicability of two smoke exhaust systems will be discussed in the project.en_US
dcterms.extentxii, 58, 14, 3 pages : color illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.educationalLevelAll Masteren_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.LCSHSmoke preventionen_US
dcterms.LCSHUnderground construction -- Fire and fire preventionen_US
dcterms.LCSHUnderground construction -- Safety measuresen_US
dcterms.accessRightsrestricted accessen_US

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