Simo Hostikka - Profile on Academia.edu (original) (raw)

Papers by Simo Hostikka

Proceeding of Proceedings of the 9th International Symposium on Radiative Transfer, RAD-19

The spectral characteristics of radiation coming from a pool fire flame are numerically obtained.... more The spectral characteristics of radiation coming from a pool fire flame are numerically obtained. The case study is a 2m n-heptane pool fire located in the bottom of a 4m×4m×5m rectangular domain. Transient heat and mass transfer of the system was solved using CFD code Fire Dynamic Simulator (FDS) with LES of turbulence and a two-step combustion reaction. The time averaged solution data of gas compositions, soot concentration and temperature along a line in the system were collected. Using the time averaged CFD data, two different onedimensional models assuming parallel plate conditions and a line of sight solution were built to study the spectral radiative intensity observed outside the flame. The high-resolution LBL spectral absorption profiles of combustion gases together with a spectral model for soot absorption coefficient were used in spectral solution of thermal radiation along the line for both assumptions of parallel plates (using DO method) and line of the sight conditions. The spectral radiation profile reaching an imaginary sensor is qualitatively compared with the recently published experimental data of Kerosene large pool fires. The modelling results revealed the strong absorption effect of cold atmospheric gases while the emission peak of hot CO2 at ~2200cm-1 in fire is still quite distinguishable from the spectral profile of hot blackbody even at 23 meters away from the center of the flame. This emission peak can be therefore used for detection of the fire. Using the scaled CFD data for smaller pools showed that the difference between the spectral profiles of the fire and those of hot blackbodies is larger for smaller pools. It means that the detection of smaller fires using the spectral radiation characteristics is easier than that of larger fires where strong effect of soot emission caused more blackbody-like behavior.

Wall response to soft impact (WARSI) and Impact loaded structures (IMPACT)

Palo-osastoinnin luotettavuuden laskennallinen arviointi

Pelastustilanteiden stokastinen operaatioaikamallinnus

Palosuojattujen polymeerien simulointi

Paineenhallinta huoneistopaloissa – tutkimushankkeen tuloksia ja suosituksia

Laivojen selviytymiskyky tulipalossa

Simulating the rescue service response in a railway tanker fire

A numerical and experimental methodology to investigate morphological changes in wood exposed to fire temperatures

International Journal of Heat and Mass Transfer, 2018

of Combustion Science and Engineering (CSE) implemented a smoke detector activation model within ... more of Combustion Science and Engineering (CSE) implemented a smoke detector activation model within FDS and also validated various parts of the model. Doug Carpenter and Erin Mack Ashley of CSE conducted the literature review that is now part of the FDS Technical Reference Guide. Jason Floyd and Javier Trelles, former NIST post-docs now working at Hughes Associates, continue to make vital contributions to the model because of their familiarity with the source code. Chris Wood of ArupFire, Dave Sheppard of the US Bureau of Alcohol, Tobacco and Firearms (ATF), and Doug Carpenter of Combustion Science and Engineering developed a training course on the use of FDS and Smokeview on behalf of the Society of Fire Protection Engineers (SFPE). Morgan Hurley of the SFPE supported this effort. Prof. David McGill of Seneca College, Ontario, Canada has also conducted a remotelearning course on the use of FDS. Prof. Ian Thomas of Victoria University has presented short courses on the use of FDS in Australia. His students have also performed some validation work on compartment fires. At the University of Maryland, Professors Fred Mowrer, Jim Quintiere, Jose Torero and Marino di Marzo have supervised students who have conducted validation work with FDS. In particular, Phil Friday and T. Ma have performed extensive validation work on the basic hydrodynamic solvers, and Paulo Ruffino has studied the activation of sprinklers that have been wetted by previously activated sprinklers. Profs. Arnaud Trouve and Andre Marshall are presently studying the application of FDS to under-ventilated fires. At Worcester Polytechnic Institute (WPI), Prof. Johnathan Barnett has supervised several students, in particular Jay Ierardi and Chris Lautenberger, who have experimented with more detailed combustion models for small-scale applications. At Northwestern University, Prof. Richard Lueptow has advised doctoral students Dave Sheppard and Jay Schwille whose research involved measurements of water sprays from sprinklers and mist nozzles. At the University of Illinois, Chicago, Prof. Ishwar Puri along with students Anurag Jhalani and Achintya Mukhopadhyay validated the model against slot burner measurements. The purpose of their study was to quantify the effects of flame stretch. At Virginia Tech, Prof. Uri Vandsburger hosted NIST Post-Doc Jason Floyd during his two-year tenure at NIST. Doctoral student Chris Wieczorek performed a series of compartment fire experiments used in part to validate FDS.

His research interests include subgrid-scale models and numerical methods for large-eddy simulati... more His research interests include subgrid-scale models and numerical methods for large-eddy simulation, adaptive mesh refinement, immersed boundary methods, and Lagrangian particle methods.

VTT Tiedotteita - Valtion Teknillinen Tutkimuskeskus

Survivability of ships in case of fire has been studied in the SURSHIP-FIRE research project as a... more Survivability of ships in case of fire has been studied in the SURSHIP-FIRE research project as a part of the SURSHIP cooperation, a coordinated European research program on Maritime safety. The work was performed in four subprojects related to materials used in shipbuilding, fire hazards on board, ship structures, and evacuation in ship conditions. Fire test data of products commonly used in shipbuilding were stored to a free-of-charge accessible database for the use of design engineers. Guidelines were defined for using fire test data in simulation and product development. Procedures for quantitative fire risk analyses of cabins and cabin areas were defined, applicable also to other cases with different features and details. A methodology for defining design fires for various ship spaces was formulated and applied to shops on board as a practical example. The sophisticated simulation and risk analysis tools utilized in the work were the FDS5 fire simulation program with its evacuation module FDS+Evac, the Probabilistic Fire Simulator, and the method of time-dependent event trees. The effects of engine room fires on car deck structures were analysed in detail since the situation was recognised critical for the structural integrity of the ship. Thermal and mechanical analyses of the structures with different dimensions and insulation extents were performed considering both the standard fire curve and the hydrocarbon curve. A survey of specific features of ship evacuation was carried out. Since the use of staircases and the movement of evacuees between decks is an essential part of ship evacuation, a new staircase submodel for the FDS+Evac program was created, verified and validated. The results of the SURSHIP-FIRE project can influence on IMO rules for alternative fire safety design of ships. The contributions of SURSHIP-FIRE are guidelines for using fire test data as input of simulations, a methodology for estimation of design fires, practices for quantitative risk analyses, a summary of critical fire situations for structures, and suggested improvements of the IMO guidelines for evacuation analyses.

Malli rakennettiin käyttäen neuroverkkojen itseorganisoituvia karttoja (SOM), jotka ovat yksi neu... more Malli rakennettiin käyttäen neuroverkkojen itseorganisoituvia karttoja (SOM), jotka ovat yksi neuroverkkojen tyyppi. Neuroverkot ovat epälineaarinen estimointimenetelmä, joiden perusajatus tulee luonnollisista neuroverkoista. Neuroverkkoa opetetaan esimerkkien avulla, ja se oppii muuttujien epälineaariset riip-5. Itseorganisoituvat kartat (SOM)

The reliability of the nuclear power plant safety systems relies strongly on the concept of redun... more The reliability of the nuclear power plant safety systems relies strongly on the concept of redundancy. In some plant designs, cables of two subsystems can exist in the same room. In this work, Monte Carlo fire simulations of this kind of cable tunnel are performed. The goal of these simulations is to estimate the time dependent probabilities of cable failures and other events in case of a cable fire starting from the power cables of one subsystem. The simulations compare consequences with and without an operating sprinkler system.

Electrical cables constitute the major part of the fire loads in nuclear power plants and may als... more Electrical cables constitute the major part of the fire loads in nuclear power plants and may also serve as ignition sources, contributing significantly to the overall risk. In this paper, the numerical methods for describing the thermal degradation of cable component materials are presented. Analytical techniques based on genetic algorithms for estimating the necessary model parameters from the small and bench scale experimental data have been used and the procedure for parameter estimation is reported. As a special topic, the modelling of the fire retardant cable materials is discussed.

Fire Safety Science, 2011

One of the most commonly used materials in electrical cables is flexible PVC. In this work, the e... more One of the most commonly used materials in electrical cables is flexible PVC. In this work, the effects of the modelling decisions and parameter estimation methods on the pyrolysis modelling of two PVC cables were studied. The kinetic and thermal parameters were estimated from TGA and cone calorimeter experiments. The role of the plasticizers was shown to be important for the early HRR. The effects of the reaction path and reaction order were only minor in the TGA results but significant effects were found in the cone calorimeter results, unless a specific set of thermal parameters was estimated. The results show that the thermal parameters estimated for one kinetic model should not be used for another, unless the kinetic models only differ in fuel yields or different pairs of kinetic coefficients with same reaction order.

Fires in nuclear power plants can be an important hazard for the overall safety of the facility. ... more Fires in nuclear power plants can be an important hazard for the overall safety of the facility. One of the typical fire sources is a pool fire. It is therefore important to have good knowledge on the fire behaviour of pool fire and be able to predict the heat release rate by prediction of the mass loss rate. This final report describes the state of the art within the area of pool fire modelling and the need for further development of pool fire models. As a result of the research in this project two new models are presented: one pyrolysis model and one engineering model. In the project the models were validated and pool fire experiments were included. Also a number of real case studies were incorporated to show the need for the development of pool fire models.