Influence of tunnel slope on smoke control
2018 (English)Report (Other academic)
Abstract [en]
The critical velocity and backlayering length in sloped tunnels are investigated by numerical simulations using FDS. Simulation in two full-scale tunnels, with negative slopes ranging up to -18 % and heat release rates from 5 to 100 MW were carried out.
The results show that NFPA 502 equation significantly overestimates the effect of negative slopes.
The equation proposed by Atkinson and Wu is found to be in closer agreement with the results. A simplified correlation, i.e. Eq. (12), is proposed and recommended for practical use.
The previous correlation for dimensionless backlayering length, Eq. (3), is valid for tunnels of various slopes and aspect ratios, and can be used for prediction of backlayering length.
Place, publisher, year, edition, pages
2018. , p. 22
Series
RISE Rapport ; 2018:50
Keywords [en]
critical velocity, tunnels, sloped tunnel, FDS
National Category
Mechanical Engineering Fluid Mechanics and Acoustics Applied Mechanics
Identifiers
URN: urn:nbn:se:ri:diva-36626ISBN: 978-91-88695-92-5 (electronic)OAI: oai:DiVA.org:ri-36626DiVA, id: diva2:1270845
Note
In the previous version there were misprints that have been corrected in the present version. The report/full text has been updated 2019-04-23 according to following corrections:
Equation (8) was given for two equations. The equation number sequence after Equation (8) has been corrected as well as references in text and graphs (2,4 and 6) to the corresponding equations.
In the previous version, Equations (8) on page 9, Equation (9) on page 11, Equation (10) on page 12 and Equation (13) on page 15 there was a misprint in the exponents for the boundaries given; a negative sign has been changed to positive sign in these equations.
2018-12-142018-12-142023-06-08Bibliographically approved