Rahul Kallada Janardhan defended his doctoral thesis

Rahul has reach a point at his research path at Aalto University, when it is time to say Goodbye! He started in Aalso’s FSE group as a MSc thesis worker in PAHAHUPA -project. From that project, he received two journal articles:

  1. Kallada Janardhan, R., Hostikka, S. Experiments and numerical simulations of pressure effects in apartment fires. Fire Technology, 53(3):1353-1377. 2017. http://doi.org/10.1007/s10694-016-0641-z
  2. Hostikka, S., Kallada Janardhan, R., Riaz, U., Sikanen, T. Fire-induced pressure and smoke spreading in mechanically ventilated buildings with air-tight envelopes. Fire Safety Journal, 91:380-388. 2017. doi:10.1016/j.firesaf.2017.04.006

Rahul’s doctoral thesis is titled “Understanding fire spread, its influence on structures and fire intervention tactics through computational methods”. You can find the thesis from https://aaltodoc.aalto.fi/handle/123456789/114663

CFD simulation of the BST/FRS wood crib fire test #2. The thesis is built on the basis of four collaborative research papers. First two developed a computational affordable (coarse mesh) CFD method for modelling fire spread on wood. Third investigated the effect of spreading fire on structural response through CFD-FEA coupling, and the fourth one introduced the aspect of fire intervention by developing a CFD model for large fire brigade water sprays and a means to consider cooling in the CFD-FEA coupling.

  1. Kallada Janardhan, R., Hostikka, S. Predictive Computational Fluid Dynamics Simulation of Fire Spread on Wood Cribs. Fire Technology, 55:2245-2268. 2019.  http://doi.org/10.1007/s10694-019-00855-3
  2. Kallada Janardhan, R., Hostikka, S. When is the fire spreading and when it travels? – Numerical simulations of compartments with wood crib fire loads. Fire Safety Journal, 126: 103485. 2021. https://doi.org/10.1016/j.firesaf.2021.103485
  3. Kallada Janardhan, R., Shakil, S., Lu, W., Hostikka, S., Puttonen, J., Coupled CFD-FE analysis of a long-span truss beam exposed to spreading fires. Engineering Structures, 259, 114150, 2022. https://doi.org/10.1016/j.engstruct.2022.114150
  4. Kallada Janardhan, R., Shakil, S., Hassinen, M., Lu, W., Puttonen, J., Hostikka, S. Impact of Firefighting Sprays on the Fire Performance of Structural Steel Members. Fire Technology, 2022. https://doi.org/10.1007/s10694-022-01257-8

Rahul’s defense was organized in June 15th, 2022. Opponent was Prof Wojciech Węgrzyński of Institute Techniki Budowlanej, Poland. The examination lasted for about two hours and covered the entire thesis work. Here is a group photo after the defense, with opponent, candidate, and custos wearing black.Group photo after Rahul's defense.

As the last project, while waiting for the reviews of his latest journal, Rahul participated in the measurements of LIESIPALO-project.

Rahul behind liesipalo chamber window

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Nordic Fire and Safety Network on Energy

We are part of the Nordic Fire and Safety Network!

The Nordic Fire and Safety Network is a consortium consisting of the Nordic universities and research institutes dealing with risk and fire safety. The network is organized by the Technical University of Denmark in collaboration with RISE (Research Institutes of Sweden), Norwegian University of Science and Technology, Lund University, Aalto University, Luleå University, University of Stavanger, Western Norway University of Applied Sciences and Iceland University as well as VTT Technical Research Centre of Finland Ltd and Danish Institute of Fire and Security Technology.

Main activities:

  • Seminars on research and education
  • Nordic Fire and Safety Days
  • PhD student workshops and summer schools
  • Researcher exchange

In fall 2021, Aalto hosted a (online) PhD student workshop on the theme of sustainability of research. Next workshop is planned for August 2022.

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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.

[embedyt] https://www.youtube.com/watch?v=RWJZI9bp868[/embedyt]

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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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