Article
Thermodynamics
Amir H. Mahdipour, M. Mahdi Salehi
Summary: The study investigates the performance of using LFD model in premixed combustion, finding that it can correctly predict filtered reaction rates and scalar fields as long as turbulent and laminar mixing are accurately predicted. Deviations from DNS results are attributed to shortcomings in the strained flamelet library and non-flamelet effects. Comparisons with another sub-filter scale model using the same strained flamelet library are made, discussing the relative performances of the two models.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Thermodynamics
Ali Kord, Jesse Capecelatro
Summary: An adjoint-based framework is developed to measure exact sensitivity from high-fidelity simulations of turbulent reacting flows. It utilizes state-of-the-art numerical methods compatible with a discrete adjoint solver and employs a flamelet/progress variable approach for chemical reactions. The framework is demonstrated through gradient-based optimization on two configurations, showcasing its efficiency in manipulating large-scale space-time fields.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Sina Kheirkhah, Omer L. Gulder
Summary: The article reviews the validity of the flamelet assumption in turbulent premixed flames and discusses the discrepancies between the assumption and actual flame behavior. It suggests that relaxing the flamelet assumption can better explain the combustion speed and behavior of turbulent premixed flames.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Sabrina Benaissa, Belkacem Adouane, S. M. Ali, Sherif S. Rashwan, Z. Aouachria
Summary: In this study, numerical simulations were used to investigate the combustion characteristics of biogas fuel blended with hydrogen in a non-premixed swirling flame. The results showed that hydrogen enrichment, equivalence ratio, and swirl numbers significantly influenced the flame macrostructure. Hydrogen enrichment intensified combustion and led to higher flame temperature and wider flammability.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Thermodynamics
Xu Wen, Ali Shamooni, Hendrik Nicolai, Oliver T. Stein, Andreas Kronenburg, Andreas M. Kempf, Christian Hasse
Summary: In this study, a carrier-phase direct numerical simulation (CP-DNS) is conducted to analyze a pulverized coal flame with flue gas recirculation (FGR). The study considers detailed gas phase kinetics and includes heavy hydrocarbon molecules. Two flamelet models are used to analyze the structure of the flame and evaluate their performance in predicting thermo-chemical quantities.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Energy & Fuels
Mustafa Ilbas, Osman Kumuk, Serhat Karyeyen
Summary: The study investigated the impact of ammonia on gas turbine combustion performance, finding that ammonia-assisted kerosene fuels have potential in terms of combustion performance, but result in higher NOX emission levels.
Article
Thermodynamics
B. Cuenot, F. Shum-Kivan, S. Blanchard
Summary: Modeling turbulent non-premixed combustion is challenging, and this study applies the Thickened Flame concept to diffusion flames, deriving a model suitable for these flames. The results demonstrate the effectiveness of the Thickened Flame concept in combustion modeling and provide an expression for the thickening factor related to mesh coarsening.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Michael Pfitzner
Summary: A new reaction rate source term omega m(c) is proposed for modeling premixed combustion with a single progress variable c. The study shows that the model performs well in terms of computational accuracy and efficiency.
FLOW TURBULENCE AND COMBUSTION
(2021)
Article
Engineering, Aerospace
Daniel Martinez-Sanchis, Andrej Sternin, Daniel Balbuena-Silvestre, Oskar J. Haidn
Summary: Two high-pressure turbulent non-premixed methane-oxygen flames were simulated to study the statistics of mixture fraction and evaluate the capability of the beta distribution and closure models for mixture fraction variance. A new closure model for mixture fraction variance was introduced, which performed well at high Reynolds numbers but had high error for moderate turbulence. It was found that the beta distribution struggled to capture extreme mixing events and the derivation of the distribution from the variance was unstable in certain configurations.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Thermodynamics
Mohammadreza Ghadimi, Hassan Atayizadeh, M. Mahdi Salehi
Summary: The study compared the performance of a joint-PDF model based on the flamelet PDF approach and a double beta-PDF model in simulating stratified flames. The results indicate that the former has slightly superior predictions of temperature, major and minor species mass fractions.
FLOW TURBULENCE AND COMBUSTION
(2021)
Article
Energy & Fuels
Filip Juric, Marko Ban, Peter Priesching, Carsten Schmalhorst, Neven Duic, Milan Vujanovic
Summary: The research focuses on reducing the impact of the transport sector on climate change and carbon dioxide emissions by utilizing biofuels and e-fuels, with the development and validation of combustion models to generate lookup databases for autoignition and laminar flame speeds under different conditions.
Article
Energy & Fuels
Lorenzo Sforza, Suliman Abdelwahid, Tommaso Lucchini, Angelo Onorati
Summary: The main challenge in improving spark ignition engines is to achieve higher thermal efficiencies and lower pollutant emissions. This study evaluates flamelet-based models using an open-source 3D-CFD platform and finds that these models cannot provide accurate and reliable results under turbulent ultra-lean premixed mixtures conditions.
Article
Energy & Fuels
Lakshmi Srinivasan, Nishanth Ram, Sudharshan Bharatwaj Rengarajan, Unnikrishnan Divakaran, Akram Mohammad, Ratna Kishore Velamati
Summary: In this paper, a 2D URANS numerical analysis is used to study the performance of an H-Darrieus VAWT. The study finds that random velocity inlet can improve the turbine's performance compared to uniform velocity inlet, with the optimal tip speed ratio being around 4.1. Additionally, the effect of wind speed fluctuations on turbine performance in a turbulent environment is analyzed using the IEC Extreme Operating Gust model. It is found that the mean coefficient of power decreases as gust amplitude increases, due to large fluctuations in incoming velocity.
Article
Chemistry, Physical
V. Pessina, F. Berni, S. Fontanesi, A. Stagni, M. Mehl
Summary: This study provides laminar flame speed correlations for ammonia/hydrogen/air mixtures under high pressure and high temperature conditions, and proposes a formula that adapts to the hydrogen content. It is of great importance for the development of suitable numerical tools for ammonia/hydrogen mixtures.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Aerospace
Milad Mohammadi, Mohammad Sadegh Abedinejad
Summary: A comprehensive investigation into non-premixed propane combustion reveals a relationship between total entropy generation rate and NO formation rate. The distribution of entropy generation serves as an indicator to predict the combustion region and main region of NO formation.
Article
Thermodynamics
Bjoern Pfeiffelmann, Ali Cemal Benim, Franz Joos
Summary: In this study, the TEG and the heat exchanger are modeled in a coupled manner using computational fluid dynamics environment. It is shown that by incorporating temperature dependent material properties in TEG and conjugate heat transfer, the performance of TEG can be effectively predicted.
HEAT TRANSFER ENGINEERING
(2021)
Article
Thermodynamics
Anil Basaran, Ali Cemal Benim, Ali Yurddas
Summary: A numerical investigation of condensing flow of isobutane inside a microchannel was conducted to determine the impact of mass flux, hydraulic diameter, and vapor quality on heat transfer rate and pressure drop. Based on validated simulations, a new correlation for heat transfer coefficient and pressure drop of isobutane condensing flow inside small-scale channels was proposed in this study.
HEAT TRANSFER ENGINEERING
(2021)
Article
Thermodynamics
Ali Cemal Benim, Cansu Deniz Canal, Yakup Erhan Boke
Summary: Computational investigation of swirling pulverized coal and biomass flames for oxy-combustion reveals that the Reynolds Stress Model (RSM) captures unsteady dynamics better than the k-epsilon model. Predicted velocities show better agreement with measurements using RSM. However, both models underestimate the measurements, with discrepancies quantified in peak values of axial velocity. Biomass flame is predicted to be nearly twice as long as coal flame.
Article
Thermodynamics
Hossain Nemati, Mohammad Moghimi Ardekani, Ali Cemal Benim, Josua Meyer
Summary: Numerical study on free convection heat transfer over annular finned tubes was conducted for over 60 different cases and verified against two experimental works. The effect of fin spacing on heat transfer was investigated, leading to the proposal of a correlation to estimate Nusselt number as a function of Rayleigh number. A general equation for optimum fin spacing was derived and compared with the results of scale analysis method, showing good agreement.
HEAT TRANSFER ENGINEERING
(2022)
Article
Thermodynamics
Cansu Deniz Canal, Yakup Erhan Boke, Ozer Aydin, Ali Cemal Benim
Summary: A computational investigation was conducted on the pulverized coal and biomass co-firing in the 150MWe unit of Tuncbilek power plant, showing that the resulting flame structure for the co-firing scenario is very similar to that of coal combustion.
ISI BILIMI VE TEKNIGI DERGISI-JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY
(2021)
Article
Energy & Fuels
Ali Cemal Benim, Cansu Deniz Canal, Yakup Erhan Boke
Summary: The computational investigation focused on a swirling pulverized coal flame, using a two-phase flow description and turbulence models including RANS and TV models. The study found that the Reynolds stress transport model (RSM) performed better than the turbulence viscosity (TV) models, especially in predicting swirl velocity. Additionally, the resolution of discrete particle phase in modelling turbulent particle dispersion and particle size distribution was examined, showing that an adequate accuracy can be achieved with a certain number of random walks and particle size classes.
Article
Energy & Fuels
Bjoern Pfeiffelmann, Ali Cemal Benim, Franz Joos
Summary: Thermoelectric generators are able to convert waste heat into electrical energy, but have not achieved broad commercial success due to low efficiency. Research on materials and system connections is crucial to improve efficiency and economic viability. Active cooling, especially in water-cooling, is preferred over passive cooling to increase net output power and exploit the full potential of TEGs.
Article
Energy & Fuels
N. S. Senthur, C. Anand, M. Ramesh Kumar, P. Elumalai, Mohamed Iqbal Shajahan, Ali Cemal Benim, Emad Abouel Nasr, H. M. A. Hussein, M. Parthasarathy
Summary: Stringent emission standards and greater fuel economy have driven scientists to develop an advanced combustion technology for future internal combustion engines. In this experiment, cobalt chromium nanoparticles were successfully mixed with citronella biodiesel using an ultrasonicator, leading to improved performance and reduced emissions in the HCCI engine.
ENERGY SCIENCE & ENGINEERING
(2022)
Article
Thermodynamics
K. Pillai Sidharth, Mattacaud R. Rajkumar, V. K. Chithrakumar, Godson L. Asirvatham, Ali Cemal Benim, Somchai Wogwises
Summary: The interplay of centrifugal and buoyant forces on convective heat transfer in a vertical annulus formed by rotating adiabatic outer cylinder and stationary heated inner cylinder has been investigated experimentally and numerically. The results show that increasing turbulence intensity improves the thermal performance of the heated inner cylinder, but the improvement becomes marginal when the rotation parameter is further increased.
Review
Chemistry, Multidisciplinary
Riheb Mabrouk, Hassane Naji, Ali Cemal Benim, Hacen Dhahri
Summary: Sharing renewable energies, reducing energy consumption, and optimizing energy management are important tasks in scientific engineering research. This paper reviews recent advancements in the sensible and latent heat storage through porous media, providing useful information for researchers and engineers in the energy storage domain. The adoption of porous matrices improves thermal performance, reduces energy consumption, and ensures thermal comfort within buildings.
APPLIED SCIENCES-BASEL
(2022)
Article
Multidisciplinary Sciences
Nirmalendu Biswas, Dipak Kumar Mandal, Nirmal K. Manna, Ali Cemal Benim
Summary: This study investigates the mixed thermo-bioconvection of magnetically susceptible fluid containing copper nanoparticles and oxytactic bacteria in a novel W-shaped porous cavity. The results show that the shape of the cavity has a significant impact on the heat and mass transfer rate.
SCIENTIFIC REPORTS
(2022)
Article
Thermodynamics
Nirmalendu Biswas, Dipak Kumar Mandal, Nirmal K. Manna, Ali Cemal Benim
Summary: This article focuses on the in-depth study of the flow physics in the bioconvection environment with a wavy heated wall in a porous setting and with the application of a magnetic field. Various emerging parameters greatly affect the thermo-magneto-bioconvective process and play critical roles in heat and mass transport dynamics.
Editorial Material
Ecology
Ali Cemal Benim
Review
Energy & Fuels
Nirmalendu Biswas, Dipak Kumar Mandal, Sharmistha Bose, Nirmal K. Manna, Ali Cemal Benim
Summary: Solar chimney power plants (SCPPs) are considered a sustainable energy option due to their low cost, abundance, low maintenance, and eco-friendliness. However, their efficiency and power generation capabilities remain limited despite optimization efforts. This comprehensive review paper aims to provide an in-depth analysis of experimental approaches and advancements in SCPPs, with the goal of facilitating commercialization.
Article
Mathematics, Interdisciplinary Applications
Ali Cemal Benim
Summary: This study computationally determines the settling velocities of three types of helminth eggs in clean tap water using computational fluid dynamics, and validates the results by comparing with previous measurements. The parametrization of egg shapes and consideration of mean shapes contribute to a better agreement with measured values, but further parameters may still affect the results.
