Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Energies energies	3.2	5.5	2008	15.7 Days	CHF 2600	Submit
Applied Sciences applsci	2.7	4.5	2011	15.8 Days	CHF 2300	Submit
Mathematics mathematics	2.4	3.5	2013	17.7 Days	CHF 2600	Submit
Entropy entropy	2.7	4.7	1999	20.4 Days	CHF 2600	Submit
Computers computers	2.8	4.7	2012	17.9 Days	CHF 1600	Submit

Open AccessArticle

Determination of 12 Combustion Products, Flame Temperature and Laminar Burning Velocity of Saudi LPG Using Numerical Methods Coded in a MATLAB Application

by

Roberto Franco Cisneros

and

Freddy Jesús Rojas

Energies 2023, 16(12), 4688; https://doi.org/10.3390/en16124688 - 13 Jun 2023

Cited by 1 | Viewed by 531

Abstract

The characterization of a specific fuel has always been an important point for developing and designing new components or systems with the maximum efficient possible. Studying the laminar burning velocity can lay a necessary prerequisite for the accurate poststudy of the turbulent range [...] Read more.

The characterization of a specific fuel has always been an important point for developing and designing new components or systems with the maximum efficient possible. Studying the laminar burning velocity can lay a necessary prerequisite for the accurate poststudy of the turbulent range and to understand how the combustion process takes place. The study of the combustion products from a specific reaction is a requisite for any system in order to understand the elements that are taken in the process and if it is possible to improve it. In this study, a new open code methodology was developed for the determination of combustion products, flame temperature and laminar burning velocity using numerical methods (Newton–Raphson, Taylor series and Gaussian elimination) in an application codified in MATLAB. The MATLAB application was applied for the study of Saudi LPG setting parameters such as initial temperature, pressure and equivalence ratio that are meaningful because they have a great effect on the results. In addition, simulation in Ansys Chemkin using San Diego and RedSD mechanisms was carried out. The results from the MATLAB application were compared with other experimental research and Ansys Chemkin simulation. These are presented in different plots and it is shown that: (1) For the laminar burning velocity results, the numerical method agrees with the experimental results for ratios (0.6–1.2) by other authors and the simulation in Ansys Chemkin. (2) For the highest studied equivalence ratios (1.3–1.7) the laminar burning velocity results between all the resources have more difference. (3) The combustion products calculated by the MATLAB application agree with those simulated in Ansys Chemkin except N and NO. (4) The MATLAB application gives a maximum value of 40.35 cm/s, that is greater than 35 ± 0.91, the one determined by Bader A. Alfarraj. (5) The flame temperature calculated by the MATLAB application overestimates that simulated in Ansys Chemkin but has the same behavior for all the calculated ratios. (6) The MATLAB application has also been developed for the study and analysis of other fuels. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

An Application of Relative Entropy in Structural Safety Analysis of Elastoplastic Beam under Fire Conditions

by

Marcin Kamiński

and

Michał Strąkowski

Energies 2023, 16(1), 207; https://doi.org/10.3390/en16010207 - 25 Dec 2022

Viewed by 895

Abstract

The main aim of this work is to propose a new algorithm of reliability assessment for steel civil engineering structures subjected to fire temperatures. This new algorithm is based upon the relative probabilistic entropy concept elaborated by Bhattacharyya, and this probabilistic distance is [...] Read more.

The main aim of this work is to propose a new algorithm of reliability assessment for steel civil engineering structures subjected to fire temperatures. This new algorithm is based upon the relative probabilistic entropy concept elaborated by Bhattacharyya, and this probabilistic distance is sought in-between extreme and admissible deformations of some structural beam subjected to higher temperatures. Similar to the First Order Reliability Method, this approach uses the first two probabilistic characteristics of the structural response, when structural output may be modelled with the use of Gaussian distribution. The probabilistic structural response is found here using hybrid computational technique–the Finite Element Method system ABAQUS with its fully coupled thermo-elastic analysis with 3D solid elements and probabilistic modules implemented in the computer algebra system MAPLE. The probabilistic response is determined via a triple stochastic analysis, which is based on the classical Monte-Carlo simulation, iterative generalized stochastic perturbation technique, and also using semi-analytical probabilistic calculus. Final determination of the relative entropy in the Serviceability Limit State of the given structure and its comparison with the results obtained using the FORM analysis enables to calibrate this new technique to numerical values proposed in the engineering designing codes. Hence, a more accurate probabilistic method may use some experimental-based admissible values included in the existing design of legal provisions. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

Power Consumption and Effectiveness of Azimuth Stern-Drive (ASD) Tug While Assisting at Ship’s Bow

by

Jarosław Artyszuk

and

Paweł Zalewski

Energies 2022, 15(24), 9519; https://doi.org/10.3390/en15249519 - 15 Dec 2022

Viewed by 1005

Abstract

The purpose of this article is to present a methodical approach to increasing the efficiency of a tug with an azimuth stern drive (ASD). The difficulties in the bow-to-bow (as a reverse tractor) operations of an azimuth stern-drive tug, while pulling at the [...] Read more.

The purpose of this article is to present a methodical approach to increasing the efficiency of a tug with an azimuth stern drive (ASD). The difficulties in the bow-to-bow (as a reverse tractor) operations of an azimuth stern-drive tug, while pulling at the assisted (towed) ship’s bow, are investigated through a parametric study. The authors’ original generic analytical model of a tug in a steady state is utilised. Various design and operation options are also compared, which cover the escort speed, hawser angle, and relative location of the towing point, among others. The latter also means a shift to stern-to-bow operation. The thruster power required and the remaining surplus for executing new alignment (steering) orders are assessed. The study is, thus, aimed at energy savings for the whole operation and, consequently, at long-term harbour-tug-fleet energy effectiveness. The basic output of the present research is the comparison of the behavioural and control patterns of various tug arrangements at a ship’s bow. The results of the study show a slight advantage for a midship winch tug working through her stern for bow operation (stern-to-bow) over the reverse tractor acting bow-to-bow. Comparing various tug designs or operation options is difficult due to complicated tug dynamics and statics patterns under the hawser action. Both relative and absolute towing forces have to be considered (a high relative force may result in a low absolute force, much less than ordered by the pilot), with some geometrical and safety constraints additionally. The practical implementation of the conducted research should cover the guidance and training rendered to tug masters in the scope of the operational limitations of a particular tug and towards the design or acquisition of the tug that is best-suited for a particular harbour operation. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

Numerical Study of the Impact of Fluid–Structure Interaction on Flow Noise over a Rectangular Cavity

by

Paweł Łojek

,

Ireneusz Czajka

and

Andrzej Gołaś

Energies 2022, 15(21), 8017; https://doi.org/10.3390/en15218017 - 28 Oct 2022

Viewed by 879

Abstract

Fluid–structure interactions (FSI) can significantly affect flow and the acoustic field generated by it. In this article, simulations of the flow over a rectangular cavity are conducted with and without taking FSI into account. The aim of this research is to conduct a [...] Read more.

Fluid–structure interactions (FSI) can significantly affect flow and the acoustic field generated by it. In this article, simulations of the flow over a rectangular cavity are conducted with and without taking FSI into account. The aim of this research is to conduct a numerical study of the flow over a cavity and to verify whether interactions between the flow and the elastic structure can significantly affect the flow itself or the acoustic pressure field. Four cases involving flexible walls with different material parameters and one reference case with rigid walls were analysed. The two-directional fluid–structure coupling between the flow and cavity walls was simulated. The simulations were performed with the volume and finite element methods using OpenFOAM software to solve the fluid field, CalculiX software to solve the displacement of the structure, and the preCICE library to couple the codes and computed fields. The acoustic analogy of Ffowcs-Williams and Hawkings and the libAcoustics library were used to calculate the sound pressure. The simulation results showed that FSI has a significant influence on sound pressure in terms of both pressure amplitudes and levels as well as in terms of noise frequency composition. There was a significant increase in the sound pressure compared to the case with rigid walls, especially for frequencies above 1 kHz. The frequencies at which this occurred are related to the natural frequencies of the cavity walls and the Rossiter frequencies. Overlap of these frequencies may lead to an increase in noise and structural vibrations, which was observed for one of the materials used. This study may provide insight into the flow noise generation mechanism when fluid–structure interactions are taken into account. The conclusions presented here can form a basis for further work on aerodynamic noise in the presence of thin-walled structures. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

Investigation of a Negative Step Effect on Stilling Basin by Using CFD

by

Lei Jiang

,

Minjun Diao

and

Chuan’ai Wang

Entropy 2022, 24(11), 1523; https://doi.org/10.3390/e24111523 - 25 Oct 2022

Cited by 1 | Viewed by 1161

Abstract

The negative-step stilling basin is an efficient and safe energy dissipator for high-head, large-unit discharge high-dam projects. However, studies of the effects of the negative step on the hydraulic performance of a high-dam stilling basin have not been conclusive. In the present study, [...] Read more.

The negative-step stilling basin is an efficient and safe energy dissipator for high-head, large-unit discharge high-dam projects. However, studies of the effects of the negative step on the hydraulic performance of a high-dam stilling basin have not been conclusive. In the present study, a 2D RANS-VOF numerical model was developed to simulate the flow field of a negative-step stilling basin. The numerical model was validated with a physical model and then used to simulate and test the performance of the negative-step stilling basin with different step heights and incident angles. The results showed that the flow pattern, the free-surface profile, the velocity profile, the characteristic lengths are strongly influenced by the step geometry. Increasing the height of the step will increase the relative flow depth and the reattachment length in the basin, but reduce the bottom velocity and the roller length. The incident angle has no significant influence on the flow pattern of the negative-step stilling basin, and increasing the incident angle of the step will reduce the bottom velocity and the reattachment length. Both the step height and the incident angle have no significant influence on the energy dissipation efficiency because of the high submergence conditions in this study. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

McCARD Criticality Benchmark Analyses with Various Evaluated Nuclear Data Libraries

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,

,

,

and

Energies 2022, 15(18), 6852; https://doi.org/10.3390/en15186852 - 19 Sep 2022

Cited by 1 | Viewed by 1017

Abstract

International Criticality Safety Benchmark Evaluation Project (ICSBEP) criticality analyses were conducted using the McCARD Monte Carlo code for 85 selected benchmark problems with 7 evaluated nuclear data libraries (ENDLs): ENDF/B-VII.1, ENDF/B-VIII.0, JENDL-4.0, JENDL-5.0, JEFF-3.3, TENDL-2021, and CENDL-3.2. Regarding the analyses, it was confirmed [...] Read more.

International Criticality Safety Benchmark Evaluation Project (ICSBEP) criticality analyses were conducted using the McCARD Monte Carlo code for 85 selected benchmark problems with 7 evaluated nuclear data libraries (ENDLs): ENDF/B-VII.1, ENDF/B-VIII.0, JENDL-4.0, JENDL-5.0, JEFF-3.3, TENDL-2021, and CENDL-3.2. Regarding the analyses, it was confirmed that the k_eff results are sensitive to the ENDL. It is noted that the new-version ENDLs show better performance in the fast benchmark cases, while on the other hand, there are no significant differences in k_eff among the different ENDLs in the thermal benchmark cases. The sensitivity of the k_eff results depending on the ENDL may impact nuclear core design parameters such as the shutdown margin, critical boron concentration, and power defects. This study and k_eff results will be a good reference in the development of new types of nuclear cores or new design codes. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

Shannon Entropy in Stochastic Analysis of Some Mems

by

Marcin Kamiński

and

Alberto Corigliano

Energies 2022, 15(15), 5483; https://doi.org/10.3390/en15155483 - 28 Jul 2022

Cited by 1 | Viewed by 819

Abstract

This work is focused on the numerical determination of Shannon probabilistic entropy for MEMS devices exhibiting some uncertainty in their structural response. This entropy is a universal measure of statistical or stochastic disorder in static deformation or dynamic vibrations of engineering systems and [...] Read more.

This work is focused on the numerical determination of Shannon probabilistic entropy for MEMS devices exhibiting some uncertainty in their structural response. This entropy is a universal measure of statistical or stochastic disorder in static deformation or dynamic vibrations of engineering systems and is available for both continuous and discrete distributions functions of structural parameters. An interval algorithm using Monte Carlo simulation and polynomial structural response recovery has been implemented to demonstrate an uncertainty propagation of the forced vibrations in some small MEMS devices. A computational example includes stochastic nonlinear vibrations described by the Duffing equation calibrated for some micro-resonators, whose damping is adopted as a Gaussian, uniformly and triangularly distributed input uncertainty source. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessFeature PaperArticle

A New Perspective on Cooking Stove Loss Coefficient Assessment by Means of the Second Law Analysis

by

Lomena Mulenda Augustin

,

Sumuna Temo Vertomene

,

Ndaye Nkanka Bernard

,

Amsini Sadiki

and

Mbuyi Katshiatshia Haddy

Entropy 2022, 24(8), 1019; https://doi.org/10.3390/e24081019 - 23 Jul 2022

Viewed by 2427

Abstract

The chimney effect taking place in biomass cooking stoves results from a conversion process between thermal and mechanical energy. The efficiency of this conversion is assessed with the stove loss coefficient. The derivation of this quantity in cooking stove modelling is still uncertain. [...] Read more.

The chimney effect taking place in biomass cooking stoves results from a conversion process between thermal and mechanical energy. The efficiency of this conversion is assessed with the stove loss coefficient. The derivation of this quantity in cooking stove modelling is still uncertain. Following fluid mechanics, this loss coefficient refers to an overall pressure drop through stove geometry by performing an energy balance according to the first law of thermodynamics. From this approach, heat-transfer processes are quite ignored yet they are important sources of irreversibilities. The present work takes a fresh look at stove loss coefficient assessment relying on the second law of thermodynamics. The purpose in this paper is to identify the influence of operating firepower level on flow dynamics in biomass natural convection-driven cooking stoves. To achieve that, a simplified analytical model of the entropy-generation rate in the flow field is developed. To validate the model, experiments are conducted first on a woodburning stove without cooking pot to better isolate physical processes governing the intrinsic behaviour of the stove. Then, for the practical case of a stove operating with a cooking pot in place, data from published literature have served for validation. In particular, mass-flow rate and flue gas temperature at different firepower levels have been monitored. It turns out that losses due to viscous dissipations are negligible compared to the global process dissipation. Exergy analysis reveals that the loss coefficient should rather be regarded from now as the availability to generate flow work primarily associated with the heat-transfer Carnot factor. In addition, the energy flux applied as flow work has to be considered as pure exergy that is lost through consecutive energy-transfer components comprising the convective heat transfer to the cooking pot. Finally, this paper reports a satisfactory agreement that emerged between the exergy Carnot factor and the experimental loss coefficient at different fuel-burning rates. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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Open AccessArticle

Rockburst Intensity Level Prediction Method Based on FA-SSA-PNN Model

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,

and

Energies 2022, 15(14), 5016; https://doi.org/10.3390/en15145016 - 08 Jul 2022

Cited by 5 | Viewed by 986

Abstract

To accurately and reliably predict the occurrence of rockburst disasters, a rockburst intensity level prediction model based on FA-SSA-PNN is proposed. Crding to the internal and external factors of rockburst occurrence, six rockburst influencing factors (σ_θ, σ_t, σ [...] Read more.

To accurately and reliably predict the occurrence of rockburst disasters, a rockburst intensity level prediction model based on FA-SSA-PNN is proposed. Crding to the internal and external factors of rockburst occurrence, six rockburst influencing factors (σ_θ, σ_t, σ_c, σ_c/σ_t, σ_θ/σ_c, W_et) were selected to build a rockburst intensity level prediction index system. Seventy-five sets of typical rockburst case data at home and abroad were collected, the original data were preprocessed based on factor analysis (FA), and the comprehensive rockburst prediction indexes, CPI₁, CPI₂, and CPI₃, obtained after dimensionality reduction, were used as the input features of the SSA-PNN model. Sixty sets of rockburst case data were extracted as the training set, and the remaining 15 sets of rockburst case data were used as the test set. After the model training was completed, the model prediction results were analysed and evaluated. The research results show that the proposed rockburst intensity level prediction method based on the FA-SSA-PNN model has the advantages of high prediction accuracy and fast convergence, which can accurately and reliably predict the rockburst intensity level in a short period of time and can be used as a new method for rockburst intensity level prediction, providing better guidance for rockburst prediction problems in deep rock projects. Full article

(This article belongs to the Topic Numerical Methods and Computer Simulations in Energy Analysis, 2nd Volume)

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