This study presents a numerical assessment of the thermodynamic and environmental performance of a hydrogen-fueled internal combustion engine using a validated zero-dimensional, single-zone model developed in OpenModelica. The engine analyzed is a single-cylinder, four-stroke, spark-ignition unit with direct hydrogen injection, based on a research platform developed at Sandia National Laboratories. The model incorporates essential submodels for engine kinematics, mass and energy balances, gas exchange, combustion heat release, heat transfer, and simplified chemical kinetics. Combustion is represented by the Wiebe function, with its parameters calibrated through comparison with experimentally measured in-cylinder pressure profiles. Initial simulations predict NOₓ emissions of 1.33 g/kWh—exceeding EURO VI regulatory limits. To address this, the study investigates direct water injection (DWI) as an emissions reduction strategy. Results demonstrate that a 10

This study investigates castor oil biodiesel as a sustainable, second-generation alternative to conventional diesel, focusing on its production, characterization, and engine performance. Biodiesel was synthesized via transesterification, achieving a 64

In this study, we investigate biodiesel extracted from castor oil as an alternative to conventional energy sources. Two significant reasons motivated the exploration of the castor plant. First, castor trees are abundant in southern Algeria, particularly in the El Oued desert. Second, the biodiesel was extracted from castor oil through catalysis with methanol, achieving a yield of around 64

Through energy and exergy analysis, the present work revisits the combustion processes generated using different fuels (CH4, C3H8, H2, LPG, Natural gas and Biogas) under the same operating conditions. First, numerical computations, in which the turbulent dynamic k-& varepsilon; model coupled with a probability density function (PDF) approach together with different sub-models that ensure the reliability of the results, are used. Then, the First and Second Laws of thermodynamics are applied to all fuel combustion cases considered previously to predict the energy loss, exergy destruction and their corresponding efficiencies. Next, variations in the air factor, the air inlet temperature and the fuel inlet temperatures are considered to analyse the response of combustion system performance as well as energy and exergy losses for the different fuels under investigation. The results show an amelioration of combustion parameters for the mixture of fuel and air using values of lambda greater than 1. Also, the preheating of the inlet air temperature has a positive effect on energetic parameters. However, preheating the inlet fuel does not take a considerable role in the efficiency amelioration and loss reduction of the combustion system. It further turns out that biogas features higher energy efficiency compared to other fuels, at approximately 89.64%, while hydrogen fuel exhibits higher exergy efficiency at around 78.70% followed by biogas with 74.96%.

In the current paper, we illustrate a numerical simulation of the non-premixed combustion in a cylindrical combustor fueled by Methane and/or Hydrogen. The aerothemochemical parameters evolutions that characterize the reacting flow are attested for different fuel compositions in the combustor. For this, the exergy loss and its functional efficiency are applied for all considered fuels to distinguish the optimum reactive mixture composition for economic combustion. Consequently, the calculations are carried out by both computational software FLUENT code package and the Cycle-Tempo Release. Then, the results proved that the hydrogen injection has an effect on all considered physic-chemical variables.

The current paper illustrates the numerical study of the global combustion parameters. It mainly focused on the computational analysis that investigated the non-premixed combustion in the cylindrical burner. Therefore, we selected many fuels to supply the burner like Algerian biogas, CH4, C3H8, H2, natural gas, and diesel to compare their aerothermochemical characteristics variables. At first, we applied the numerical methods that confirm the solution convergence like combustion models and grid selection. After that, we resolved the aerothermochemical set equations of combustion using the coupled k-ɛ turbulent dynamic model with the probability density function approach. These models are also used to surmount the closer in the set of combustion equations too. Moreover, we integrated the pollutant computation model based on the chemical reactions of NO production. Thus, we evaluated each considered fuel’s NO emission during all combustion fuels cases. Accordingly, the results show that Algerian biogas and hydrogen have special characteristics compared to other cases of fuels. The most prominent characteristics are: the high level of the mixture and burn relative to other fuels, their low pollutants emissions (CO and NO), and the proportional relationship between the OH and NO production. Consequently, biogas and H2conserve the impact on energy and the environment.

The paper presents a thermodynamic analysis of an existing ISCC power plant when running at off-design operation conditions. The off-design regime is due to changes in air temperature and DNI. The analysis is based on the results of calculations performed by the flow sheet programme 'Cycle-Tempo'. For off-design modelling, some reasonable assumptions are adopted in regard to the operations of the turbomachines and heat exchangers. The power plant performance is examined when it is running following the operation strategy 'saving mode'. The complementarily between the solar field and the duct burners (DBs), and the operation of the power plant, in terms of hourly net electricity output and thermal efficiency, are analysed on two representative days, a summer day and a winter day. The key parameters in the study are essentially the HTF mass flow rate, DB fuel consumption, thermal energies supplied by the solar field, and the DBs.

The present study aimsto characterize the behavior and the efficiency of a new biocomposite material based on cement mortar and reinforced with natural palm fibers both in terms of energy saving in buildings and indoor environmental quality. For this purpose, the hygric behavior of this material was investigated in terms of moisture buffer, where the material was exposed to cyclic humidity variation at isothermal conditions. The study highlights the effect of temperature and hysteresis on the moisture content within the material. The results showed that date palm fiber concrete has excellent moisture buffering capacity witha good ability for heat regulation, thanks to its moisture sorption behavior and its high thermal insulation capacity.

The present work investigates the energy and exergy analysis for some fuels supplied the cylindrical combustion chamber. Indeed, this work is focused on the comparison of the different carbon based fuels to the H2 fuel as a reference case. After that, the energy and exergy analysis are applied for all fuels compositions, in order to select the fuel corresponding to the optimum combustion for the considered burner in this work. The computations are performed with the use of the Cycle-Tempo Release package code. Finely, the obtained results in this study illustrate that the hydrogen is the best fuel in the considered configuration.

The present investigation illustrates a computational study of the turbulent diffusion flame in a cylindrical burner that is confined by two coaxial jets (methane/hydrogen and air). This is to improve the reactive mixture, the reactants combustion and to reduce the concentration of carbon monoxide as pollutant chemical species. The coupled models LES/PDF are, hereby, used to surmount the turbulence/chemistry interaction in the transport equations of chemical species. The predicted mixture fraction, the progress variable, and the carbon monoxide mass fraction are selected to validate the coupled models with respect to the experimental references data. Furthermore, the same scalar parameters which are considered in the previous numerical validation are evaluated from different fuel compositions of the hydrogen and the methane percentage to supply the combustion chamber. The computed results are carried out by FLUENT-CFD; where, they prove that hydrogen addition reduces the carbon monoxide concentration in the combustion products and improves the reactants combustion caused by the rich mixture.

The paper presents a numerical thermal analysis concerning the operation of the solar receiver Schott PTR-70 under the running conditions of Hassi R'Mel power plant. The analysis is based on numerical resolution by finite difference method of a 1D transient modelling of heat transfer balances taking place in the receiver. At first, a modelling validation against experimentally determined correlations issued from NREL facility tests is given. The comparison and confirmation are in terms of thermal efficiency and linear heat loss of the receiver versus HTF average temperature. Then, a discussion is developed about how the production of hot HTF (392 degrees C) varies versus DNI intensity for four typical days each representative of a season? Afterwards, it is concluded that the enhancement of heat convective transfer between the absorber and the HTF would have no positive effect on HTF mass flow rate.

Hygrothermal behavior of a new building material, composed of cement, sand and date palm fibers was investigated in the present work. In a first part, the sorption-desorption isotherms and the hysteresis effect were characterized under static conditions, and collected results revealed a high hydric capacity of this Date Palm Cement (DPC) mortar. In addition, the GAB model (Guggenheim-Anderson-de Boer) was successfully applied to describe the experimental sorption isotherm curve. In a second step, the moisture buffer value and the effect of temperature on successive adsorption/desorption cycles were assessed under dynamical conditions. It was found that the sorption process is highly affected by temperature. Finally, this bio-based mortar was classified as hygroscopic and breathable material with excellent moisture buffering capacity.

: The present work aims to study the hygrothermal behavior at wall scale of a new biocomposite material made with concrete reinforced with natural fibers. The outdoor climate conditions were simulated using a climatic chamber on the one side of the wall, while the conditions of temperature and relative humidity on the other side of the wall were maintained at constant values. The temperature and relative humidity were monitored at different depths of the wall using sensors. Several hygric phenomena were highlighted such as homogeneous vapor diffusion and huge vapor pressure variations due to the evaporation-condensation and sorption-desorption phenomena. Besides, significant thermal and hygric inertia was observed through the Date Palme Concrete (DPC) wall. The response time of our biocomposite wall is relatively short for temperature variation compared to the humidity ones.

In this paper, the numerical results of the study of a turbulent flame of methane-hydrogen/air generated by a cylindrical burner are presented. The numerical simulations are carried out using the CFD code "FLUENT" and "Gambit" for the meshing process. The finite volume method was used to solve the Navier-Stokes equations governing the flow. The coupling of the LES/PDF models is used to model the turbulence/chemistry interaction in the system's transport equations. The results of the calculations are expressed and analyzed in terms of axial velocity, temperature and mass fraction of carbon monoxide CO. The results of the numerical calculations are compared and validated against experimental data. In addition, the same parameters considered above are used in the study of the combustion behavior of CH4/H2 fuels. The obtained results confirm the fact of considering hydrogen as a clean nonpolluting fuel compared to methane, since it has no carbon monoxide emissions in combustion products. Besides this fact, the hydrogen gas velocity in the flame is significantly higher by comparing it to the methane gas velocity. Key words— Non-Premixed Combustion; Turbulence; Hydrogen; Methane; CFD Simulation.

This paper presents the operating and performance of an adsorption refrigeration system driven by a solar collector. The thermodynamic cycle and the working principle of the system are based on the adsorption phenomena at a steady temperature. The system operates with activated carbon (AC) methanol as a working pair, and Dubinin-Astakhov CD-A) equation was used to describe this phenomena. Comparative study between different types of AC reveals that the one based on stone coal had an optimal performance coefficient (COP) equal to 0.73 whereas a total energy input to the system is 18740.05 kJ and a total daily ice production of 13.65 kg at -3 degrees C. The studied case indicates that the optimal performance of the system can be obtained for low ambient and condensation temperature with high evaporation temperature. Ice produced can also be improved when the initial water temperature is low. (C) 2016 Elsevier Ltd. All rights reserved.

This study presents a numerical investigation of the effects of mixing methane/hydrogen on turbulent combustion processes taking place in a burner similar to that integrated in gas turbine power plants. Thereby, in comparison to the reference case where the burner is fuelled by 100% of methane, the variations of the axial velocity field, temperature field and mass fraction of carbon monoxide field are examined for different percentages of hydrogen fuel injection. The computed results, obtained by using the software Fluent-CFD, are compared and validated against experimental reference data. Results show that the hydrogen addition to the methane has an impact on all physical and chemical parameters of the reactive system.

Thermodynamic irreversibilities generated by the combustion process are evaluated and analyzed numerically. The numerical simulation is performed for a reference case study for which experimental data are available in the literature: diffusion flame properties in a common burner configuration are studied by the Fluent software with the standard k–ε turbulence model and two-step chemical reaction. The study quantifies the contribution of each mechanism to entropy generation, i.e., friction, heat conduction, species diffusion, and chemical reaction. The chemical reaction and heat conduction are found to be the major sources of entropy production. Preheating of air reduces thermodynamic irreversibilities within the combustor.

This study presents a numerical investigation on the proton exchange membrane fuel cell (PEMFC) and the solid oxide fuel cell (SOFC), using the aerothermal and electrochemistry equations to describe all phenomena included in both types of the fuel cells. The computational process is based on the implementation of the mathematical fuel cells models in FLUENT computational fluid dynamics code. This is in order to evaluate the temperature field, the production of the electricity, and the distribution of the water mass fraction in different region of the fuel cells. The obtained results show that the simulation is able to evaluate the physical and chemical parameters to explain the main phenomena in the fuel cells.

This work is focused on the analysis of various computed terms of entropy generation rate in the gaseous combustion processes at different inlet temperatures of air and CH4. Therefore, the expression of the entropy generation rate includes the effect of the viscosity friction, the thermal diffusion, the species diffusion and the chemical reaction. The expressions have been used for each term of entropy generation in order to examine the influence of each one in the overall system.