CFD results are discussed for jet flows through a straight square duct, which is an interesting configuration in the context of air curtain flows for smoke and heat control in buildings in case of fire. The CFD package Fire Dynamics Simulator, Version 6.0.1, is used. Special focus is given to the impact of the inlet boundary condition on the flow field in the near-field region. Investigation of different orifice configurations (W = 2 cm width, variable span-wise length), including calculations inside a straight square duct (2 cm × 2 cm, with variable length) ahead of the air orifice, reveals a small vena contracta effect when the orifice is flush with a solid boundary, leading to an acceleration of the flow in the symmetry plane in the near-field region. The vena contracta effect disappears if the co-flow at the nozzle exit is aligned with the jet. More important is the effect of the duct length (precursor domain length, serving as method to generate inflow turbulent conditions for the main computation): imposing a top hat velocity profile, a sufficiently long duct (i.e., L = 20W) is required for the flow to become fully developed at the orifice. The CFD results confirm an analytical correlation for the ratio of the entrance length to the hydraulic diameter of the duct as function of the Reynolds number, provided the duct width is used as characteristic length scale. Using a sufficiently fine mesh, i.e., 10 cells across the characteristic dimension of the nozzle, the evolution of the mean and RMS stream-wise velocity along the centerline, as well as their profiles across the nozzle width, are shown to be captured accurately in the CFD results.
Fire Technology – Springer Journals
Published: Dec 14, 2017
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera