Multiphysics simulation of stone-wool fire resistance

Our publicly funded project on the multiphysics simulation of stone-wool fire resistance is now ending. In this project, we studied the thermal behaviour of stone wool and developed simulation models to extend the standard test results. The project was made in collaboration with Owens Corning Paroc who provided experimental test data from 30 different stone wool samples.

The work was published in Fire Technology.

The work was funded by Palosuojelurahasto.

The main conclusions were

  • Stone wool, as other non-combustible, A1 class insulation materias contain varying amounts of organic materials that react with oxygen during fire, and produce heat that increases wool temperature even tens of degrees.
  • Temperature increase is highest in stone wools with high organic content, but the amount of organic content alone does not explain the whole phenomenon. It is necessary to consider the transport of oxygen too.
  • The processes can be best simulated with models that include both heat conduciton, mass transfer, and heterogenous reactions.
  • Closing the stone wool between non-permeable linings, like steel sheets in sandwich elements, will prevent oxygen diffusion into the wool, and reduce the cold-side temperatures.

 

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Effect of ventilation and behaviours on aerosol-spreading and Covid-19 infections

Simo posted at LinkedIn about the calculation of infection risk and aerosol concentrations in closed spaces with ventilation. This was a result of consultation with public transport -related actors in Finland. In the end of the post, there will be links to a GitHub space with matlab-functions.

 

 

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The new cone calorimeter of Aalto FSE research group

 

The new cone calorimeter of our research group, manufactured by Concept Equipment Ltd. in UK, has been freshly commissioned and is now entering its research use. Cone calorimeter is a widely used tool in fire performance testing of materials. In principle, the sample is ignited and burned below a truncated cone -shaped heater element, imposing a radiant heat flux in order of tens of kilowatts per square meter. The released smoke gases are collected and analyzed to give heat release rate and other data, while also recording the sample mass. In the figures, the burning sample is of black PMMA plastic.

In addition to the standard testing in atmospheric conditions as in the figures, our new cone calorimeter has also a tailor-made capability to materials testing in reduced oxygen concentrations. This is achieved by closing the doors and vents on the sides of the sample chamber, inserting roof panels on its top, and flushing the chamber with a nitrogen flow from below the sample.

Posted by Aleksi Rinta-Paavola

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Simo’s installation talk on Fire computing

To celebrate the tenured position of Associate professor, Simo gave his Installation talk in the Aalto-level event, January 30, 2019.

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Thermal Radiation Seminars and Workshop in The University of Tehran and Sharif University of Technology

In Dec 2018, Hadi Bordbar gave a keynote speech at the 9th National Conference on CFD Applications in Chemical and Petroleum Industries hosted by the University of Tehran. The title of the speech was High Fidelity Modeling of Spectral Thermal Radiation in Combustion Systems. He also ran a half day workshop of numerical modeling of thermal radiation in combustion systems in the University of Tehran.

 

The same seminar was also given in Sharif University of Technology. The event was hosted by the research group of Prof. Masood Darbandi in Dep. of Aerospace Engineering and Center for Development of Modern Energy Systems.

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Infradex Thermal Imaging Seminar in Aalto

Hadi Bordbar hosted “BRING THE HEAT” seminar in Aalto presented by FLIR in partnership with Infradex. Representatives of these two companies exhibited their up-to-date thermal imaging technologies and cameras during a 2 hours seminar. The event was free and open to all the Aalto’s employees and students. The participants received the certificate of attendance.

         Thermal bridge around a window

   Thermal portrait of some members of Aalto Fire Safety Eng. Group

from left: Rahul Janardhan, Aleksi Rinta-Paavola, Hadi Bordbar, Deepak Paudel, Simo Hostikka

 

The companies awarded a thermal imaging camera to Aalto Fire Safety Eng. group in compensations of Hadi Bordbar’s efforts in organizing the event. Here is a video of its unboxing ceremony 🙂

 

 

 

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Spring 2019 visitors and new members in Aalto FSE team

We had a pleasure to welcome new members and short-term visitors to the FSE team:

Ada Malagnino (right) from the University of Salento, Italy, is visiting our group for six months. Her PhD topic deals with the management of safety design and fire safety assessment during building renovations. The focus is on the utilization of Building Information Modelling on fire safety management.

Guilherme Fraga (left) is a PhD student at Universidade Federal Do Rio Grande Do Sul,  Brazil. His research topic is turbulence-radiation interaction, and he has already implemented different spectral models of radiation medium into FDS. The purpose os Guilherme’s short visit is to make some of these models available for all FDS users, and to investigate if we can improve the accuracy of radiation predictions with WSGG models.

Eetu Veikkanen (middle) started his MSc thesis on the effectiveness of fire sprinklers in protecting the life safety of patients in hospital fires. He will analyze the data that we collected with VTT in fall 2018 in Sysmä.

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Two doctoral positions open in the FSE group

New things are coming! We are hiring two new doctoral students to the team:

First is about the numerical simulation of spectral thermal radiation in condenced phase materials. Hadi will be the advisor for this thesis – the best possible person you can imagine!
https://www.aalto.fi/careers/doctoral-candidate-in-numerical-modelling-of-thermal-radiation-in-fires

The second one will contribute to the international OECD PRISME3 fire test project by performing CFD simulations of the cable tunnel fires.
https://www.aalto.fi/careers/doctoral-candidate-in-numerical-simulation-of-fire-spreading-on-electrical-cables

 

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Aalto FSE group in NFSD 2018

The Nordic Fire and Safety Days was held in Trondheim, Norway on 7.-8. June this time. From the Aalto fire safety engineering group, Prof. Simo Hostikka and doctoral students Aleksi Rinta-Paavola, Deepak Paudel and Teemu Isojärvi attended the conference. Prof. Hostikka had the honor of giving the first keynote lecture, with title “Handling overpressure and ventilation in modern building fires”, and discussing the risk of dangerous overpressure development when accidental fires occur in modern airtight buildings.

Aleksi Rinta-Paavola was awarded the prize for this year’s best fire science master’s thesis (congratulations!), and gave a presentation “Numerical simulation of passive fire protection systems”.

Aleksi Rinta-Paavola receiving his Master’s thesis award at NFSD 2018.

Deepak Paudel presented his work in a talk titled “Modeling uncertainty in the prediction of wall temperature in compartment fires”. In his presentation, Deepak showed that we can take into account the model uncertainty when we use deterministic models for probabilistic fire risk assessments.

Teemu Isojärvi had a presentation titled “Radiation transmittance through the liquid phase in an n-heptane pool fire“. The work is, to our knowledge, the first time when k-distribution method is used for liquid material radiation calculations.

Some of the presentations will be shared publicly in ResearchGate.

The event was a great opportunity to connect with other people working on either the practical or scientific aspects of fire safety. Now looking forward to the ESFSS 2018 symposium, to be held in Nancy, France in September.

Posted by rahul

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Aalto FSE group: Summer trip to Suomenlinna

The fire safety engineering group visited the historic Suomenlinna fortress (UNESCO World heritage site) on 11th June. It was fun, exploring the tunnels and basking in the evening sun by the coast, as we watched the cruise set sail towards Stockholm.

 

 

PC: Hadi Bordbar, Deepak Paudel & Tito Adibaskoro

 

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