Opportunities

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: Charred residues formed during solid thermal decomposition strongly influence the course of fire spread. For wood-based materials, the char layer serves as an effective thermal barrier that substantially reduces heat transfer to the underlying material, thereby significantly slowing the progression of further thermal degradation and combustion. To account for the influence od char residue in advanced mathematical models of fire, its thermal properties are required. However, these residues are typically porous and fragile materials, making the determination of their properties particularly challenging.

The aim of this thesis is to apply photogrammetry to determine the bulk density of residues produced by the combustion of various wood-based panel materials. Photogrammetry is a technique that enables three-dimensional reconstruction of object geometry using photographs or video recordings captured from multiple angles.

As part of the project, the student will become familiar with photogrammetric methods and software tools used for 3D object reconstruction. The work will also include an assessment of measurement accuracy.

Experimental investigations will be carried out on samples differing in material type, different charring histories and environments, and sampling location within the tested specimens.

Related video: A short introduction to photogrammetry presented by our students at the Night of Scientists (Noc vědců): https://www.nocvedy.cz/archiv/udalost/2745-mereni-objemu-pomoci-fotografie-a-jeho-vyuziti-v-pozarnich-prumyslu.

Supervisor: Vojtěch Šálek
Advisor: Milan Jahoda

Annotation: Wood-based materials are widely used in construction and building interiors due to their favourable mechanical properties, availability, and renewability. However, their combustible nature may significantly contribute to fire development. Modern fire models are capable of predicting fire growth as well as the thermal response of materials and structures, but their accuracy depends on the availability of reliable material properties. One of the key input parameters is thermal conductivity, which may vary considerably with temperature.

This thesis focuses on reviewing the available data on the thermal conductivity of wood-based materials and the methods used for its determination. The thermal conductivity of selected materials will be experimentally measured over the widest possible temperature range using the Transient Hot Bridge (THB) method. The measured values will be compared with data reported in the literature and evaluated with respect to their use as input parameters for fire modelling.

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: The thermal decomposition of wood-based materials during fire exposure is accompanied by the formation of a char layer. The rate of char formation, commonly referred to as the charring rate, describes the speed at which the boundary between charred and uncharred material progresses into the material. It is a practical engineering parameter widely used in structural fire design to estimate the reduction of the load-bearing cross-section without the need for detailed modelling of heat transfer and pyrolysis.

In practice, the position of the char front is difficult to determine directly during fire exposure. Instead, it is commonly approximated by the penetration of a characteristic temperature, typically around 300 °C, into the material. The thesis will first provide a literature review of existing approaches for determining charring rate, including experimental techniques, commonly adopted evaluation criteria, and published data for wood and wood-based materials under different thermal exposure conditions. Building on this review, temperature profiles within wood-based panels will be experimentally determined during controlled heating. Based on the measured data, the charring rate will be evaluated and compared under different thermal decomposition conditions.

Particular attention will be paid to the influence of oxygen availability by comparing oxidative conditions (representative of flaming combustion) with inert conditions (corresponding to oxygen-limited environments encountered in ventilation-controlled fires). The study will investigate selected wood-based panel products, such as particleboard, MDF, and OSB, and evaluate the applicability of the commonly adopted 300 °C criterion under different conditions. The experimentally determined charring rates will be compared with values reported in the literature and those adopted in engineering design standards, providing new insights into the influence of oxidation on charring behaviour. The experiments will be carried out in cooperation with the Technical Institute of Fire Protection in Prague–Modřany.

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: Accurate determination of heat flux is one of the key challenges in experimental fire research. Heat flux governs ignition, flame spread, and thermal degradation of materials and therefore represents one of the most important quantities for the validation of computational fire models. In recent years, considerable attention has been devoted to separating the total heat flux into its radiative and convective components, as this distinction is essential for understanding fire dynamics and improving the predictive capability of numerical models. Beyond model validation, knowledge of the dominant heat transfer mechanism is also relevant for practical fire safety applications, including firefighter exposure assessment and the evaluation of thermal environments inside burning compartments.

The thesis will briefly review heat flux measurement techniques used in fire research, including water-cooled and uncooled heat flux gauges, methods for separating radiative and convective heat transfer, and current approaches adopted in experimental and numerical studies. Depending on the student's interests, the thesis may focus primarily on experimental measurements, numerical modelling, or a combination of both.

The experimental part of the thesis will focus on fire experiments conducted in a reduced-scale compartment based on the ISO 9705 room configuration developed by NIST for fire model validation. Various fire scenarios and ventilation conditions will be investigated to evaluate the applicability of heat flux separation using water-cooled heat flux gauges and plate thermocouples. The experimental work will be carried out in collaboration with the Technical Institute of Fire Protection within the KVAN_SAL research project (see Projects).

For the numerical part, a computational fire model of the experimental configuration will be developed and validated against the measured data. The resulting dataset will contribute to the validation of computational fire models and to a better understanding of radiative and convective heat transfer in compartment fires.

Supervisor: Milan Jahoda
Advisor: Lucie Hasalová

Annotation:  Knowledge of flame temperature is essential for assessing the impact of fire on its immediate surroundings, such as the design of fire protection systems, fire spread prediction, and the safety of firefighters during emergency response. However, determining flame temperature using commonly employed thermocouples is far from straightforward, as a thermocouple measures the temperature of its sensing junction rather than the actual gas temperature.

Supervisor: Milan Jahoda
Advisor: Lucie Hasalová

Annotation:  Knowledge of the radiant heat flux emitted by flames and acting on surrounding objects is of great importance in fire safety engineering. Measurements are typically performed using commercial heat flux sensors, which are relatively expensive and therefore often used only to a limited extent during fire testing.

Supervisor: Vojtěch Šálek
Advisor: Milan Jahoda

Annotation: Soot particles are an inevitable product of incomplete combustion and play a key role in fire dynamics. They strongly influence thermal radiation, reduce visibility, contribute to smoke toxicity, and affect the transport of combustion products throughout a fire compartment. Consequently, accurate prediction of soot production is essential for reliable numerical simulations of fire development and smoke movement.

Despite their importance, soot formation remains one of the most challenging processes to model because it involves complex chemical and physical mechanisms occurring over a wide range of spatial and temporal scales. For this reason, most engineering fire models, including the Fire Dynamics Simulator (FDS), employ simplified approaches in which soot production is represented by prescribed soot yields rather than being predicted from detailed soot formation kinetics. The applicability of these simplified models therefore relies heavily on validation against high-quality experimental data. However, quantitative measurements of soot concentration during compartment fire experiments remain relatively scarce.

The thesis will begin with a literature review on experimental methods for soot concentration measurements with particular attention to gravimetric sampling techniques, and optical measurement methods. The experimental part of the thesis will focus on the development and optimization of a soot sampling methodology using filter-based gravimetric measurements. Different sampling conditions, including sampling location, flow rate, and sampling duration, will be evaluated to establish a reliable procedure for determining soot concentration. The developed methodology will be applied during fire experiments conducted in a reduced-scale compartment specifically designed for fire model validation. The resulting dataset will provide valuable experimental data for the validation and improvement of numerical fire models. The experiments will be carried out in cooperation with the Technical Institute of Fire Protection in Prague–Modřany.

Supervisor: Milan Jahoda
Advisor: Lucie Hasalová, Vojtěch Šálek

Annotation: Fluid flow is one of the fundamental phenomena governing fire development. Together with heat conduction and thermal radiation, convective heat transfer determines the thermal environment within a fire compartment and strongly influences flame spread, smoke movement, oxygen transport, and the distribution of combustion products. Consequently, reliable measurements of gas velocity are essential for the validation of computational fire models.

The thesis will begin with a literature review of experimental techniques used for velocity measurements in fire conditions. The review will cover commonly employed methods such as Pitot tubes, hot-wire and particle image velocimetry (PIV). Their operating principles, advantages, limitations, achievable accuracy, cost, and applicability to high-temperature fire environments will be critically assessed. Particular attention will be paid to directional sensitivity, the measurement of velocity vectors versus velocity magnitude, spatial resolution, and the influence of near-wall flow conditions on measurement accuracy.

The experimental part of the thesis will investigate selected velocity measurement techniques using a reduced-scale compartment specifically developed as a fire model validation scenario. The resulting experimental data will contribute to the development of a reliable methodology for velocity measurements in compartment fire experiments and provide valuable validation data for computational fire models. The findings are expected to support future studies on fire dynamics by improving the experimental characterization of convective flow and its interaction with heat transfer processes. The experiments will be carried out in cooperation with the Technical Institute of Fire Protection in Prague–Modřany.

Supervisor: Milan Jahoda
Advisor: 

Annotation: The development of hydrogen mobility is not possible without a well-established understanding of fire safety. The fire safety aspects of hydrogen use in energy systems and transportation have been described relatively well in the scientific literature from a theoretical perspective. Nevertheless, several important questions remain unanswered. One of these concerns the characterization of the time-dependent discharge of hydrogen from a pressurized storage vessel through a pressure relief device when it is activated, for example due to elevated ambient temperatures caused by a vehicle fire. It is known that hydrogen, unlike compressed natural gas (CNG), does not cool significantly during expansion and release. Gas discharge can be modeled using approaches ranging from simple analytical outflow models to advanced three-dimensional Computational Fluid Dynamics (CFD) simulations.

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: Wood-based materials are widely used in building interiors, such as offices and laboratories, where they may significantly contribute to fire growth and fire spread. Numerical fire models can be used to predict the fire behaviour of office furniture assemblies; however, their accuracy depends on the quality of the input material data and the approach used to model the thermal decomposition of solid materials. The recently introduced Scaling Pyrolysis (SPyro) approach enables the use of experimental data obtained from bench-scale tests (cone calorimetry) to determine pyrolysis parameters for fire simulations.

This thesis focuses on the analysis of experimental dataset from large-scale fire tests of furniture assemblies conducted in a Room Corner Test apparatus. Based on experimental data obtained using a cone calorimeter, a fire model employing the Scaling Pyrolysis approach will be developed in the Fire Dynamics Simulator (FDS). The objective of the thesis is to evaluate the ability of this approach to predict fire spread and the heat release rate during a full-scale furniture assembly fire.

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: Accurate determination of heat flux is one of the key challenges in experimental fire research. Heat flux governs ignition, flame spread, and thermal degradation of materials and therefore represents one of the most important quantities for the validation of computational fire models. In recent years, considerable attention has been devoted to separating the total heat flux into its radiative and convective components, as this distinction is essential for understanding fire dynamics and improving the predictive capability of numerical models. Beyond model validation, knowledge of the dominant heat transfer mechanism is also relevant for practical fire safety applications, including firefighter exposure assessment and the evaluation of thermal environments inside burning compartments.

The thesis will briefly review heat flux measurement techniques used in fire research, including water-cooled and uncooled heat flux gauges, methods for separating radiative and convective heat transfer, and current approaches adopted in experimental and numerical studies. Depending on the student's interests, the thesis may focus primarily on experimental measurements, numerical modelling, or a combination of both.

The experimental part of the thesis will focus on fire experiments conducted in a reduced-scale compartment based on the ISO 9705 room configuration developed by NIST for fire model validation. Various fire scenarios and ventilation conditions will be investigated to evaluate the applicability of heat flux separation using water-cooled heat flux gauges and plate thermocouples. The experimental work will be carried out in collaboration with the Technical Institute of Fire Protection within the KVAN_SAL research project (see Projects).

For the numerical part, a computational fire model of the experimental configuration will be developed and validated against the measured data. The resulting dataset will contribute to the validation of computational fire models and to a better understanding of radiative and convective heat transfer in compartment fires.

Supervisor: Vojtěch Šálek
Advisor: Lucie Hasalová

Annotation: Cone calorimetry is one of the most widely used experimental methods for characterizing the fire behaviour of materials. The technique is based on exposing the upper surface of a flat specimen to a prescribed external heat flux and is commonly used to determine material fire properties such as the heat release rate (HRR), effective heat of combustion, ignition time, and mass loss rate. In addition to material characterization, cone calorimeter experiments are increasingly employed for the calibration and validation of advanced pyrolysis models used in computational fire simulations.

The thesis will begin with a brief literature review of numerical modelling approaches for cone calorimeter experiments, with particular emphasis on the assumptions commonly adopted regarding specimen geometry, thermal boundary conditions, and one-dimensional heat transfer. Special attention will be paid to methods used for representing the thermal insulation of specimen edges and the implications of these assumptions for the prediction of temperature fields and pyrolysis behaviour.

The practical part of the thesis will focus on developing a three-dimensional numerical model of the cone calorimeter to investigate the influence of thermal boundary conditions on heat conduction within wood-based panels. Different approaches for modelling the insulation of specimen edges will be evaluated and compared with the commonly adopted one-dimensional approximation. The resulting temperature distributions will be analysed to assess under which conditions the one-dimensional assumption remains valid and when three-dimensional effects become significant. The outcomes of the study will contribute to improving the reliability of pyrolysis model calibration and provide recommendations for the numerical simulation of cone calorimeter experiments.

Supervisor: Vojtěch Šálek
Advisor: Jiří Ira, Milan Jahoda

Annotation: The rate of thermal decomposition of solid materials is a governing process in predicting fire spread within advanced fire models. This rate is commonly described using Arrhenius-type kinetics; however, for chemically complex materials such as wood, it is impossible to explicitly represent the hundreds of decomposition reactions that occur simultaneously. Therefore, an engineering approach is required to identify an appropriate simplified decomposition scheme together with the corresponding optimal kinetic parameters. These parameters must be determined in such a way that the model accurately reproduces the mass-loss behavior observed in experimental measurements.

The aim of this project is to develop an open-source desktop application with a graphical user interface (GUI) for the Windows operating system. The application serves for processing experimental thermogravimetric data with the aim of calculating the kinetics parameters of thermal decomposition. The application will implement: reading and smoothing of experimental datasets; the K–K method for estimating the number of decomposition reactions; choice of various decomposition reaction schemes; and optimization routine to obtain kinetic parameters.