Jiahao Hu , Zhan Wang , Zhi Tang , Hongzheng Li , Can Wang , Zheng Fang
{"title":"Study on the applicability of scaling laws in tunnel fires under natural ventilation conditions","authors":"Jiahao Hu , Zhan Wang , Zhi Tang , Hongzheng Li , Can Wang , Zheng Fang","doi":"10.1016/j.firesaf.2025.104349","DOIUrl":null,"url":null,"abstract":"<div><div>This article numerically investigates the impact of tunnel scale ratio and fire Heat Release Rate (HRR) on the scaling results of temperature distribution and smoke field in a tunnel under natural ventilation conditions, by preserving Froude (Fr) scaling. Computational fluid dynamics simulations were performed on a 1:8 scale physical tunnel model [1], showing satisfactory agreement between measured data and predicted results. On this basis, four additional numerical models with scales of 1:1, 1:2, 1:4, and 1:16 were built based on Froude scaling principles, considering the scaling of thermal properties of materials and wall thickness. Four HRRs ranging from 3 MW to 50 MW were adopted. The simulation results provide insights into the temperature and flow fields, revealing the influence of tunnel scale ratio, HRR, and wall scaling method on scaling errors. Significant discrepancies found in the smallest tunnel model with a scale ratio of 1:16 were well explained by transitional or laminar flow due to low Reynolds number (Re), which can primarily cause a significant reduction in ceiling jet temperature as well as an increase in smoke arrival time and smoke thickness. Finally, after analyzing scaling errors for practical tunnel fire design scenarios, recommendations are provided for engineering application of selecting appropriate physical scale models for tunnel fire tests.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":"152 ","pages":"Article 104349"},"PeriodicalIF":3.4000,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fire Safety Journal","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S037971122500013X","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
引用次数: 0
Abstract
This article numerically investigates the impact of tunnel scale ratio and fire Heat Release Rate (HRR) on the scaling results of temperature distribution and smoke field in a tunnel under natural ventilation conditions, by preserving Froude (Fr) scaling. Computational fluid dynamics simulations were performed on a 1:8 scale physical tunnel model [1], showing satisfactory agreement between measured data and predicted results. On this basis, four additional numerical models with scales of 1:1, 1:2, 1:4, and 1:16 were built based on Froude scaling principles, considering the scaling of thermal properties of materials and wall thickness. Four HRRs ranging from 3 MW to 50 MW were adopted. The simulation results provide insights into the temperature and flow fields, revealing the influence of tunnel scale ratio, HRR, and wall scaling method on scaling errors. Significant discrepancies found in the smallest tunnel model with a scale ratio of 1:16 were well explained by transitional or laminar flow due to low Reynolds number (Re), which can primarily cause a significant reduction in ceiling jet temperature as well as an increase in smoke arrival time and smoke thickness. Finally, after analyzing scaling errors for practical tunnel fire design scenarios, recommendations are provided for engineering application of selecting appropriate physical scale models for tunnel fire tests.
期刊介绍:
Fire Safety Journal is the leading publication dealing with all aspects of fire safety engineering. Its scope is purposefully wide, as it is deemed important to encourage papers from all sources within this multidisciplinary subject, thus providing a forum for its further development as a distinct engineering discipline. This is an essential step towards gaining a status equal to that enjoyed by the other engineering disciplines.