• I am interested in advancing numerical and experimental research of spectral radiation heat transfer and multiphase flow in energy conversion processes.
• I am interested in implementing modern machine learning techniques and artificial intelligence in modeling, analyzing, and designing engineering applications.
• I am committed to the ongoing research of Energy and Fire Protection Engineering.
• I am an experienced teacher trained with up-to-date knowledge and skills of modern pedagogy with enduring records of teaching BSc, MSc, and Ph.D. courses in Mechanical, Energy, and Civil Engineering.
• Having more than 20 years of experience in the research and development of energy and environmental technology, I have innovative and practical leadership skills to manage and lead research and development teams in relevant interdisciplinary fields such as fire protection engineering.
• With multicultural background and experience, equipped with remarkable soft skills, I am always looking for new collaboration and networking possibilities.
• I am a highly effective presenter of research results interested in interdisciplinary research using physical- and data-based approaches together with AI and other modern techniques.
Improving the efficiency, sustainability and reducing the environmental penalty in energy conversion systems have been the main motives of my research for the last 18 years. The main tool that I have been using to achieve these fascinating goals is numerical modeling. Numerical modeling, including CFD, statistical methods and modern machine learning methods, provides a flexible, economical and yet reliable way to analyze and understand the physics of different energy conversion processes, which is otherwise very complex, expensive and time-consuming to gain by experiments. Development of reliable modeling capabilities will help design engineers to optimize the process design in terms of energy efficiency and emission control of various energy conversion systems with sufficient information that can not be acquired experimentally. By energy conversion systems, I mean all parts of energy systems from generation to consumption systems. From boilers and powerplants to HVAC, engines and bulidings.
According to the European Commission, buildings account for 40% of the energy consumption and 36% of the CO2 emissions in the EU. It highlights the importance of improving energy efficiency of buildings in overall economy and environment. In addition, safety and air quality are two other main factors, which are directly affected by the thermal conditions of the airflow inside and outside of the buildings. Therefore, I'm using numerical modulation in order to analyze heat and mass transfer in buildings to provide Insights which help designers imporve the energy efficiency, air quality and safety of bulidings.
Numerical modeling of radiation heat transfer, multiphase flow hydrodynamics, spectral radiation and chemical combustion are of my main research interest.
I am a mechanical engineer with a passion for numerical and experimental study of complex multi-physics phenomena such as fires. Being fascinated by fast-growing computational resources, I conducted most of my research toward developing numerical models for complex physical phenomena that occur in various energy conversion processes. My work covers a wide range from the development of numerical models for thermal radiation, fire detection, fire dynamics, pyrolysis to modeling virus-laden two-phase respiratory flows, collisions of granular particles, continuum and discrete element models for dense gas-particle flows, and oxygen-fired combustion.
2. Previous research
2.1. Doctoral research
My doctoral research had an ambitious research goal of developing a numerical model for the physics of a highly complex system of dense granular materials subjected to vertical vibration. Performing experiments for the collision of binary multisize granular particles, I presented a contact-force model for viscoelastic particle collisions [1, 2]. I also developed a continuum model and a discrete element model for hydrodynamics of dense granular materials in different flow regimes [3,4] by accounting for the particle-particle collision and particle-wall collision details. As a result, they provided greater insight toward the explanation of poorly understood hydrodynamic phenomena in the field of granular flows and dense gas-particle mixtures such as bubbling , heaping , and oscillons . In addition, the models were generalized to investigate the granular material-container wall interactions, which would be highly interested in many industrial applications such as ideal processing conditions and powder transport in the chemical and power industry.
2.2. Postgraduate research
Within my postdoctoral research, I initiated a new research field at the Lappeenranta University of Technology, Finland. I focused on developing fast and accurate models to solve radiation heat transfer in modern combustion systems. The primary applications were the modern carbon capture and storage (CCS) techniques used in power generation systems such as oxygen-fired combustion and other turbulent reactive flow such as fire. I applied some innovative techniques to the classical zone method and developed two new versions of the model [7, 8], which were considerably faster and more accurate than the classical one. It is beneficial for the applications needing quick analysis of thermal radiation, for instance, in real-time modeling for controlling industrial processes or in simulations of large-scale fires such as wildfires with coarse computational grids. It has been used to solve the radiation heat transfer in several industrial large scale combustion systems such as furnace of recovery boilers , pulverized coal boilers , circulating fluidized bed (CFB) furnaces [7, 11], and a large back pass of a CFB boiler [8, 12].
The spectral thermal radiation of molecular gases in combustion systems was another subject that attracted my interest. Due to millions of absorbing and emitting lines existing in the thermal radiation spectrum of molecular gases and their dependency on temperature, gas concentration, and pressure, spectral thermal radiation is complicated and computationally expensive to model. In this regard, I visited the research group of Professor Michael Modest, one of the most well-known scientists in this field, at the University of California-Merced. There, I had the chance to work on implementing different spectral radiation models in OpenFOAM for CFD simulation of thermal radiation in multiphase combustion systems such as internal combustion engines.
I developed several simplified global models, including the weighted sum of gray gas models (WSGG) and the full-spectrum correlated-k method (FSCK), to affordably include spectral radiation of combustion gases in thermal radiation calculations. I proposed a new formulation for the WSGG model, which includes the molar fraction ratio of H2O to CO2 as a variable. It, therefore, solved gas spectral radiation in heterogeneous combustion environments much more accurately . In addition, the range of applicability of this model is recently extended; it is now the only WSGG model that supports the entire range of molar fraction ratio of H2O to CO2 from zero to infinity  and non-atmospheric pressures . It essentially makes the model capable of modeling pressurized and microgravity combustion in general CFD frameworks. Using this model, I simulated several industrial combustors, including the furnace of a large circulating fluidized bed boiler , and the back pass channel of an oxygen-fired CFB boiler . I also provided a simple, fast, and accurate band model to account for non-gray boundary wall conditions [16, 17], which may be the case in solar receivers, for instance, and in spectral-based fire detectors. I also obtained an artificial neural network for gray band absorption coefficients of combustion gases.
I have developed a comprehensive code for line-by-line (LBL) calculation of very high-resolution absorption spectra of combustion gases [15, 17].Using the high fidelity LBL data, we developed 3D large-scale benchmarks , which can validate other simpler models.
3. Current research
At the beginning of 2018, I joined the fire safety engineering research group at the school of Engineering of Aalto University, Finland. As a member of Professor Simo Hostikka’s research team, I am leading the research related to thermal radiation modeling and experiments in fires. I propose, conduct and supervise the related research, including three doctoral studies on thermal radiation in fires. Below are some of my current activities:
3.1. Improving thermal radiation solvers in fire CFD codes
We advance the radiation heat transfer solver in the open-source code of Fire Dynamics Simulator (FDS). Our focus is on improving the spectral radiative properties of the combustion gases and soot by implementing the global models. Improvement of narrowband code of RADCAL for calculating radiative properties in FDS and implementing global models such as WSGG, FSCK, and RCSLW in FDS and FireFOAM are only parts of our activities in this field.
3.2. Development of global modes for fuel gases
Absorption of the fuel-rich region above the condensed fuels in fires significantly affects the flame radiation feedback. It, therefore, needs to be included in the radiation solution of the gas phase. We use the spectral absorption data of fuel vapors at various temperatures to develop global spectral models, including WSGG and full-spectrum correlated k-method (FSCK) for fuel vapors. Developing efficient mixing schemes for combining the new fuels’ global models with those of other gases and soot is part of my ongoing research. Following my previous fundamental works in gas spectral radiation [13, 14, 15, 16, 17], I develop novel models with various capabilities for gas and soot spectral radiation in fires.
3.3. High fidelity modeling of in-depth radiation penetration to study flammability of condensed materials in fire
We also study the radiation penetration into condensed phases involved in fire scenarios. In-depth radiation absorption in liquid hydrocarbons and solid polymers is the primary source of evaporation, pyrolysis, and decomposition. It, therefore, has a significant role in the spreading and evolution of fires. We study spectral radiation transfer into the condensed phase materials numerically and experimentally through FTIR and UV-Vis spectroscopy. We conducted very fine spectroscopy to obtain the detailed absorption spectra of clear and black PMMA. Using the high fidelity spectral data of various fuels, we solved the spectral dependency of in-depth radiation by developing novel full-spectrum correlated-k models [19, 20, 21].
Furthermore, we developed a new model to solve the directional dependency (i.e., the Fresnel effect) of the boundary’s irradiation . The new model solves the Fresnel effect more efficiently than the previously developed models. Implementing these fine treatments of the directional and spectral dependences of thermal radiation, we currently advance the modeling capability of pyrolysis and ignition time of PMMA in different flammability experiments of cone calorimeter and fire propagation apparatus (FPA).
3.4. Novel measurement and sensing technologies for thermal radiation of unwanted fire
Though detecting fires through its unique radiative characteristics is a well-established technology, there is no detailed insight into their detection method and especially their spectral characteristics in the open literature. It formed the motivation of this work. Moreover, we obtained more details of the efficiency of the infrared spectrum-based detection strategy. We develop an optimized flame detection strategy by analyzing the available high-resolution emission spectra of fire and hot blackbody emitters obtained either experimentally or numerically .
The feasibility of fire detection by three or four low-pass optical filters is studied. Utilizing the detailed, recently published spectral data, we evaluate the effects of the fire size (i.e., optical thickness), atmospheric conditions, and filter quality on the possibility to distinguish flames from other hot objects. We review the feasibility of designing new micro-composite high/low-pass filters and combining them with the gradient heat flux sensor chips to implement the introduced detection strategy. It is a highly multidisciplinary project in which four
different research groups from various disciplines collaborate. I am the coordinator of the project.
3.5. MaCFP Workgroup for Thermal Radiation
I currently co-coordinate a newly formed workgroup to advance the modeling capability of thermal radiation in fires. The Thermal radiation subgroup shares the central objective of MaCFP “to target fundamental progress in fire science and to advance predictive fire modeling”. The specific goals of the subgroup focus on the development, calibration, verification, and validation of predictive models of radiative heat transfer in various fire scenarios. The workgroup is formed to improve spectral databases' accuracy for modeling radiative heat transfer in gas and condensed phases. We aim to provide a general guideline for estimating the mean beam length used in gray models. The implementation of global spectral models such as WSGG, FSCK, and SLW and efficient consideration of interactions of radiative heat transfer with chemistry and turbulence in fire modeling tools are among the main objectives of the new workgroup.
 M. H. Bordbar and T. Hyppänen, "Modeling of Binary Collision between Multisize Viscoelastic Spheres," Journal of Numerical Analysis, Industrial and Applied Mathematics, vol. 2, no. 3-4, pp. 115-128, 2007.
 P. Zamankhan and M. H. Bordbar, "Complex Flow Dynamics in Dense Granular Flows–Part I: Experimentation," J. Appl. Mech, vol. 73, p. 648–657, 11 2005.
 M. H. Bordbar and P. Zamankhan, "Dynamical states of bubbling in vertical vibrated granular materials. Part II: Theoretical analysis and simulations," Communications in Nonlinear Science and Numerical Simulation, vol. 12, pp. 273-299, 2007.
 M. H. Bordbar and P. Zamankhan, "Dynamical states of bubbling in vertically vibrated granular materials. Part I: Collective processes," Communications in Nonlinear Science and Numerical Simulation, vol. 12, pp. 254-272, 2007.
 M. H. Bordbar, "Advances in Numerical Simulation of Granular Materials," in Numerical Simulation Research Progress, Nova Science Publisher, 2009, pp. 257-287.
 M. H. Bordbar and T. Hyppänen, "Simulation of Bubble Formation and Heaping in a Vibrating Granular Bed," Chemical Engineering Communications, vol. 198, pp. 905-919, 2011.
 . M. H. Bordbar and T. Hyppänen, "Multiscale numerical simulation of radiation heat transfer in participating media," Heat Transfer Engineering, vol. 34, pp. 54-69, 2013.
 M. H. Bordbar and T. Hyppänen, "The correlation based zonal method and its application to the back pass channel of oxy/air-fired CFB boiler," Applied Thermal Engineering, vol. 78, pp. 351-363, 2015.
 M. H. Bordbar and T. Hyppänen, "Simulation of Radiation Heat Transfer of Three Dimensional Participating Media by Radiative Exchange Method," in Proceeding of the 2008 ASME Heat Transfer Conference, Published in CD-ISBN 0-7918-3832-3, Jacksonville, USA, 2008.
 M. H. Bordbar and T. Hyppänen, "Modeling of Radiation Heat Transfer in a Boiler Furnace," Adv. Studies Theor. Phys., vol. 1, no. 12, pp. 571-584, 2007.
 M. H. Bordbar, K. Myöhänen and T. Hyppänen, "Coupling of a radiative heat transfer model and a three-dimensional combustion model for a circulating fluidized bed furnace," Applied Thermal Engineering, vol. 76, pp. 344-356, 2015.
 M. H. Bordbar and T. Hyppänen, "The effect of combustion type on the radiation heat transfer in back pass channel of a CFB boiler," in Proceeding of the 3rd IEA GHG International Oxyfuel Combustion Conference (OCC3),, Ponferrada, Spain., 2013.
 M. H. Bordbar, G. Wecel and T. Hyppänen, "A line by line based weighted sum of gray gases model for inhomogeneous CO2–H2O mixture in oxy-fired combustion," Combust. Flame, vol. 161, p. 2435–2445, 2014.
 H. Bordbar, G. Fraga and S. Hostikka, "An Extended Weighted-Sum-of-Gray-Gases Model to Account for All CO2-H2O Molar Fraction Ratios in Thermal Radiation," International Communications in Heat and Mass Transfer, vol. Submitted, March 2019.
 H. Bordbar, F. R. Coelho, G. C. Fraga, F. H. R. França and S. Hostikka, "Pressure-dependent weighted-sum-of-gray-gases models for heterogeneous CO2-H2O mixtures at sub- and super-atmospheric pressure," International Journal of Heat and Mass Transfer, vol. 173, p. 121207, 2021.
 H. Bordbar, A. Maximov and T. Hyppänen, "Improved banded method for spectral thermal radiation in participating media with spectrally dependent wall emittance," Applied Energy, vol. 235, pp. 1090-1105, 2019.
 H. Bordbar and T. Hyppänen, "Line by line based band identification for non-gray gas modeling with a banded approach," International Journal of Heat and Mass Transfer, vol. 127, pp. 870-884, 2018.
 G. C. Fraga, H. Bordbar, S. Hostikka and F. H. R. França, "Benchmark Solutions of Three-Dimensional Radiative Transfer in Nongray Media Using Line-by-Line Integration," J. Heat Transfer, vol. 142, 1 2020.
 T. Isojärvi, H. Bordbar and S. Hostikka, "Spectrally resolved calculation of thermal radiation penetration into liquid n-heptane in pool fires," International Journal of Heat and Mass Transfer, vol. 127, pp. 1101-1109, 2018.
 F. Alinejad, H. Bordbar and S. Hostikka, "Development of full spectrum correlated k-model for spectral radiation penetration within liquid fuels," International Journal of Heat and Mass Transfer, vol. 158, p. 119990, 2020.
 F. Alinejad, H. Bordbar and S. Hostikka, "Improving the modeling of spectral radiation penetration into the condensed materials with the separated full spectrum correlated-k method," International Journal of Heat and Mass Transfer, vol. 176, p. 121448, 2021.
 F. Alinejad, H. Bordbar and S. Hostikka, "The ordinate weighting method for solving radiative heat transfer through a Fresnel interface," Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 270, p. 107685, 2021.
 H. Bordbar, S. Hostikka, P. Boulet and G. Parent, "Numerically resolved line by line radiation spectrum of large kerosene pool fires," Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 254, p. 107229, 2020.
Research and teaching on different subjects of thermo-fluid engineering with focus on numerical modeling of energy conversion systems formed a significant part of my work at graduate level. I have been deeply involved in researching the state of the art in modeling techniques used to simulate heat and mass transfer in various energy systems. I finished my doctoral study in Dec. 2005 at LUT (Lappeenranta University of Technology) in which I conducted a comprehensive theoretical, numerical and experimental study of multiphase flow in vertically vibrated granular materials. After completing my doctoral study, I joined the newly established research group of Professor Timo Hyppänen at LUT in 2006.There I initiated a new field of research in LUT for advancing the state of the art of numerical modeling of radiative heat transfer in combustion systems. Since that time, I have been working on several research projects including number of national TEKES projects, Academy of Finland research projects and EU research projects under different job titles such as postdoctoral researcher, senior researcher and associate professor (Tutkija-opettaja in Finnish). Meanwhile, I had two terms of research mobility at the research group of Professor Modest at the University of California-Merced and the "Energy-2050" research group at the University of Sheffield. Through these visits and attending many related conferences, I have established a network with the world-recognized frontiers in the field of modeling of energy systems. From Feb. 1st , 2018, I started working as a staff scientist at the Department of Civil Engineering of Aalto University.
During the past 18 years, I have been actively involved in many research projects either as a researcher, leader or project manager. The common goal of all of them was to pave the way for implementing the world's limited energy resources in a sustainable way. My main interests were development of more efficient and clean energy conversion processes. Development of numerical tools and models for different physical phenomena existing in energy conversion processes have been part of my activities. I presented several models for radiation heat transfer modeling in combustion systems. I also developed several models for fluid dynamics, reaction and mass transfer in multiphase flow systems including different types of fluidized bed combustors, dense granular material, etc.
However, I strongly believe that one successful research team should not be limited to certain research topics and should always look for new ideas and challenges. Armed with strong fundamental knowledge in physics, thermodynamics, heat transfer and fluid mechanics, one can be active in different energy related research feilds with varient applications.
My interest in extending my research activities is to move towards new sustainable energy sources such as solar energy and bridge between my previous experiences and skills and the current challenges in new sustainable energy conversion systems.
My teaching experience includes teaching a variety of subjects including the basic courses of Thermos-Fluid Engineering to numerical modeling and the practical courses such as power plant design and energy efficient building design. I supervised undergraduate students in their major research projects, under the direction of the course instructor and BSc thesis supervisor. I also cosupervised a doctoral student at LUT in 2008-2012. Through this experience, I have developed excellent communication, solving problem and organizational skills. My skills in teaching would be beneficial with the development of new programs at the undergraduate and graduate level.
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