Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.75713
S. Vasily, Zhmailo Vadim, Yanilkin Yury
The paper presents an overview of benchmarks for non-ideal magnetohydrodynamics. These benchmarks include dissipative processes in the form of heat conduction, magnetic diffusion, and the Hall effect.
本文概述了非理想磁流体力学的基准。这些基准包括热传导、磁扩散和霍尔效应形式的耗散过程。
{"title":"Benchmarks for Non-Ideal Magnetohydrodynamics","authors":"S. Vasily, Zhmailo Vadim, Yanilkin Yury","doi":"10.5772/INTECHOPEN.75713","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75713","url":null,"abstract":"The paper presents an overview of benchmarks for non-ideal magnetohydrodynamics. These benchmarks include dissipative processes in the form of heat conduction, magnetic diffusion, and the Hall effect.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126110940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.75660
D. Karadimou, N. Markatos
The numerical simulation of fluid flow and heat/mass-transfer phenomena requires the numerical solution of the Navier-Stokes and energy-conservation equations coupled with the continuity equation. Numerical or false diffusion is the phenomenon of inserting errors in the calculations that compromise the accuracy of the computational solution. The Taylor series analysis that reveals the truncation/discretization errors of the differen- tial equations terms should not be termed as false diffusion. Numerical diffusion appears in multi-dimensional flows when the differencing scheme fails to account for the true direction of the flow. Numerical errors associated with false diffusion are investigated via two- and three-dimensional problems. A numerical scheme must satisfy necessary criteria for the successful solution of the convection-diffusion formulations. The common practice of approximating the diffusion terms via the central-difference approximation is satisfactory. Attention is directed to the convection terms since these approximations induce false diffusion. The equations of all the conservation equations in this study are discretized by the finite volume method.
{"title":"Study of the Numerical Diffusion in Computational Calculations","authors":"D. Karadimou, N. Markatos","doi":"10.5772/INTECHOPEN.75660","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75660","url":null,"abstract":"The numerical simulation of fluid flow and heat/mass-transfer phenomena requires the numerical solution of the Navier-Stokes and energy-conservation equations coupled with the continuity equation. Numerical or false diffusion is the phenomenon of inserting errors in the calculations that compromise the accuracy of the computational solution. The Taylor series analysis that reveals the truncation/discretization errors of the differen- tial equations terms should not be termed as false diffusion. Numerical diffusion appears in multi-dimensional flows when the differencing scheme fails to account for the true direction of the flow. Numerical errors associated with false diffusion are investigated via two- and three-dimensional problems. A numerical scheme must satisfy necessary criteria for the successful solution of the convection-diffusion formulations. The common practice of approximating the diffusion terms via the central-difference approximation is satisfactory. Attention is directed to the convection terms since these approximations induce false diffusion. The equations of all the conservation equations in this study are discretized by the finite volume method.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121653029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.76611
K. Dalma, Kovacs Melinda Haydee
Emerging chemical compounds are ubiquitous in all environmental compartments and may pose a risk to biota ecosystems. The quantification and prediction of environmental partitioning of these chemicals in various environmental compartment systems (water, sediments, soil, air, biota) is an important step in the comprehensive assessment of their sources, fates, and not finally of their uptake potential by various living organisms of ecosystems. Any numerical solution that has as a final goal “prediction” requires a large number of experimental data. In case of environmental studies of chemical compounds, monitoring most studies is costly, time-consuming, and requires both qualified personnel and high- precision equipment. Finding a suitable numerical model that could predict the fate of chemicals could be extremely useful, facilitating those environmental scientists, users, managers, authorities, and corresponding decision-makers for a more conscious use of these substances, thus protecting the environment and biota. Considering the mentioned disadvantages regarding chemical compounds’ monitoring, the aim of this research is to find numerical solutions that enable the prediction of such chemical compounds’ fate under different environmental compartments and the uptake potential by living organisms as plants. The concept of the inverse numerical method was used in order to find chemical compounds’ rate of accumulation in various environ- mental matrixes and potential uptake by living organisms, all starting from the chemical compounds’ concentrations.
{"title":"Numerical Modeling of Chemical Compounds’ Fate and Kinetics in Living Organisms: An Inverse Numerical Method for Rate Estimation from Concentration","authors":"K. Dalma, Kovacs Melinda Haydee","doi":"10.5772/INTECHOPEN.76611","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.76611","url":null,"abstract":"Emerging chemical compounds are ubiquitous in all environmental compartments and may pose a risk to biota ecosystems. The quantification and prediction of environmental partitioning of these chemicals in various environmental compartment systems (water, sediments, soil, air, biota) is an important step in the comprehensive assessment of their sources, fates, and not finally of their uptake potential by various living organisms of ecosystems. Any numerical solution that has as a final goal “prediction” requires a large number of experimental data. In case of environmental studies of chemical compounds, monitoring most studies is costly, time-consuming, and requires both qualified personnel and high- precision equipment. Finding a suitable numerical model that could predict the fate of chemicals could be extremely useful, facilitating those environmental scientists, users, managers, authorities, and corresponding decision-makers for a more conscious use of these substances, thus protecting the environment and biota. Considering the mentioned disadvantages regarding chemical compounds’ monitoring, the aim of this research is to find numerical solutions that enable the prediction of such chemical compounds’ fate under different environmental compartments and the uptake potential by living organisms as plants. The concept of the inverse numerical method was used in order to find chemical compounds’ rate of accumulation in various environ- mental matrixes and potential uptake by living organisms, all starting from the chemical compounds’ concentrations.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129108050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.75490
J. Oliveira
Numerical simulation of complex and heterogeneous electronic systems can be a very challenging issue. Circuits composed of a combination of analog, mixed-signal and digital blocks or even radio frequency (RF) blocks, integrated in the same substrate, are very difficult to simulate as a whole at the circuit level. The main reason is because they contain a lot of state variables presenting very distinct properties and evolving in very widely separated time scales. Examples of practical interest are systems-on-a-chip (SoCs), very common in mobile electronics applications, as well as in many other embedded electronic systems. This chapter is intended to briefly review some advanced circuit-level numerical simulation techniques based on circuit-block partitioning schemes, which were especially designed to address the simulation challenges brought by this kind of circuits into the computer-aided-design (CAD) field.
{"title":"Numerical Simulation of Electronic Systems Based on Circuit- Block Partitioning Strategies","authors":"J. Oliveira","doi":"10.5772/INTECHOPEN.75490","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75490","url":null,"abstract":"Numerical simulation of complex and heterogeneous electronic systems can be a very challenging issue. Circuits composed of a combination of analog, mixed-signal and digital blocks or even radio frequency (RF) blocks, integrated in the same substrate, are very difficult to simulate as a whole at the circuit level. The main reason is because they contain a lot of state variables presenting very distinct properties and evolving in very widely separated time scales. Examples of practical interest are systems-on-a-chip (SoCs), very common in mobile electronics applications, as well as in many other embedded electronic systems. This chapter is intended to briefly review some advanced circuit-level numerical simulation techniques based on circuit-block partitioning schemes, which were especially designed to address the simulation challenges brought by this kind of circuits into the computer-aided-design (CAD) field.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114137652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.75615
A. Wahrhaftig, R. Brasil, Lázaro S. M. S. C. Nascimento
For a complete analysis of vibration, the stiffness of a structure must have two character- istics: one corresponding to conventional stiffness and the other to the geometric stiffness. Thus, the total stiffness takes form where the model to be used to represent any behavior of the material is introduced to the first part via the modulus of elasticity. The second is the geometric stiffness, through which it is possible to linearize a geometric nonlinear prob- lem. To consider both aspects, a mathematical model based on the Rayleigh method has been elaborated. Two systems were numerically studied. First, the occurrence of reso- nance in the vibration of a prestressed reinforced concrete beam has been investigated. The results indicated resonant and non-resonant schemes between the natural frequency of the beam and the frequency of the engine. To the second system, the first natural frequency of a slender, 40-m-high concrete mobile phone mast, was calculated, and an evaluation of the structural collapse was performed. To the both systems, the cross section of reinforced concrete was treated by the theory for the homogenized section in order to consider the presence of the steel, and the viscoelasticity of the concrete was taken into account through a three-parameter rheological model.
{"title":"Analytical and Mathematical Analysis of the Vibration of Structural Systems Considering Geometric Stiffness and Viscoelasticity","authors":"A. Wahrhaftig, R. Brasil, Lázaro S. M. S. C. Nascimento","doi":"10.5772/INTECHOPEN.75615","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75615","url":null,"abstract":"For a complete analysis of vibration, the stiffness of a structure must have two character- istics: one corresponding to conventional stiffness and the other to the geometric stiffness. Thus, the total stiffness takes form where the model to be used to represent any behavior of the material is introduced to the first part via the modulus of elasticity. The second is the geometric stiffness, through which it is possible to linearize a geometric nonlinear prob- lem. To consider both aspects, a mathematical model based on the Rayleigh method has been elaborated. Two systems were numerically studied. First, the occurrence of reso- nance in the vibration of a prestressed reinforced concrete beam has been investigated. The results indicated resonant and non-resonant schemes between the natural frequency of the beam and the frequency of the engine. To the second system, the first natural frequency of a slender, 40-m-high concrete mobile phone mast, was calculated, and an evaluation of the structural collapse was performed. To the both systems, the cross section of reinforced concrete was treated by the theory for the homogenized section in order to consider the presence of the steel, and the viscoelasticity of the concrete was taken into account through a three-parameter rheological model.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125387485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-11DOI: 10.5772/INTECHOPEN.71224
N. Akbar, D. Tripathi, Zafar Hayat Khan
The effects of different typesof base fluidsoncarbon nanotube(CNT) nanofluids flow over a circular stretching sheet are numerically analyzed. The nonlinear variation of radial velocity in radial direction is assumed at surface of stretching sheet. The temperature dependent fluid viscosity is taken into consideration. Two different types of flows (assisting flow and opposing flow) are discussed under the buoyant force effects. Single walled CNT and multi walled CNT are considered as nanoparticles for better thermal conductivity of the nanofluids. A set of similarity transformations to convert the partial differential equations into ordinarydifferentialequations is hired.The non-linearODEsare numerically solved by employing fourth order Runge-Kutta method. Discussions of numerical simulations for flow characteristics have been made appropriately. A compara-tive study for various type of base fluids like kerosene, engine oil and ethylene glycol is also presented. From the predicted simulation, it is observed that the variation in Nusselt number is maximum for engine oil and minimum for kerosene oil however, the variation in skin friction coefficient is largest for kerosene oil and least for engine oil. Furthermore, numerical results are also validated with achieving a goodcorrelation with existing results.
{"title":"Numerical Simulation of Nanoparticles with Variable Viscosity over a Stretching Sheet","authors":"N. Akbar, D. Tripathi, Zafar Hayat Khan","doi":"10.5772/INTECHOPEN.71224","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.71224","url":null,"abstract":"The effects of different typesof base fluidsoncarbon nanotube(CNT) nanofluids flow over a circular stretching sheet are numerically analyzed. The nonlinear variation of radial velocity in radial direction is assumed at surface of stretching sheet. The temperature dependent fluid viscosity is taken into consideration. Two different types of flows (assisting flow and opposing flow) are discussed under the buoyant force effects. Single walled CNT and multi walled CNT are considered as nanoparticles for better thermal conductivity of the nanofluids. A set of similarity transformations to convert the partial differential equations into ordinarydifferentialequations is hired.The non-linearODEsare numerically solved by employing fourth order Runge-Kutta method. Discussions of numerical simulations for flow characteristics have been made appropriately. A compara-tive study for various type of base fluids like kerosene, engine oil and ethylene glycol is also presented. From the predicted simulation, it is observed that the variation in Nusselt number is maximum for engine oil and minimum for kerosene oil however, the variation in skin friction coefficient is largest for kerosene oil and least for engine oil. Furthermore, numerical results are also validated with achieving a goodcorrelation with existing results.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124005013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-11DOI: 10.5772/INTECHOPEN.75586
José Trinidad Guillen Bonilla, Héctor Guillen Bonilla, A. Zamora, G. A. Gómez, Nancy Elizabeth Franco Rodríguez, Alex Guillen Bonilla, Juan R. Gómez
In this work, the twin-grating fiber optic sensor has been applied on wavelength-division multiplexing. A quasi-distributed sensor formed by three local twin-grating sensors, is numerically simulated. The wavelength channels were 1531.5, 1535.5, and 1539.5 nm. The numerical simulation shows the resolution vs. signal-to-noise rate. Three local twin-grating sensors have approximately the same resolution because all local sensors have the same cavity length and the wavelength channels are very close. All local sensors have two numerical resolutions because the Fourier domain phase analysis algorithm makes two evaluations of the Bragg wavelength shift. The transition between both resolutions can be calculated with the parameters: cavity length, Bragg wavelength channel, refrac- tion index, and enveloped resolution. This transition depends on the noise system, demodulation algorithm, instrumentation, and local sensor properties. A very important point is, a theoretical analysis will permit to know the exact resolution for each local twin-grating sensor.
{"title":"Twin-Grating Fiber Optic Sensors Applied on Wavelength- Division Multiplexing and Its Numerical Resolution","authors":"José Trinidad Guillen Bonilla, Héctor Guillen Bonilla, A. Zamora, G. A. Gómez, Nancy Elizabeth Franco Rodríguez, Alex Guillen Bonilla, Juan R. Gómez","doi":"10.5772/INTECHOPEN.75586","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75586","url":null,"abstract":"In this work, the twin-grating fiber optic sensor has been applied on wavelength-division multiplexing. A quasi-distributed sensor formed by three local twin-grating sensors, is numerically simulated. The wavelength channels were 1531.5, 1535.5, and 1539.5 nm. The numerical simulation shows the resolution vs. signal-to-noise rate. Three local twin-grating sensors have approximately the same resolution because all local sensors have the same cavity length and the wavelength channels are very close. All local sensors have two numerical resolutions because the Fourier domain phase analysis algorithm makes two evaluations of the Bragg wavelength shift. The transition between both resolutions can be calculated with the parameters: cavity length, Bragg wavelength channel, refrac- tion index, and enveloped resolution. This transition depends on the noise system, demodulation algorithm, instrumentation, and local sensor properties. A very important point is, a theoretical analysis will permit to know the exact resolution for each local twin-grating sensor.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121825540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-04-09DOI: 10.5772/INTECHOPEN.75935
J. A. Castro, B. A. Pereira, Roan Sampaio deSouza, E. M. Oliveira, I. Ferreira
This chapter describes the numerical simulations of a coupled industrial scale of the tundish and continuous casting process. The governing equations are presented, and the numerical procedure is discussed in a common framework. The coupled solutions are presented for the transient turbulent flows within the tundish, solidifying zone and extracting regions with the coupling phenomena of heat and mass transfer. The tundish region flow and refractory are calculated using the inlet and outlet boundary conditions in order to estimate the filling phenomena. The transitions and cooling zones for the thin slab continuous casting process are designed to account for the control of the solidified skin in order to avoid breakout. We compared the numerical predictions of the temperatures with industrial monitoring data for a reference case in order to verify the consistence of the model predictions. A parallel version of the numerical code is proposed aiming to improve the computation time keeping numerical accuracy.
{"title":"Numerical Study of Turbulent Flows and Heat Transfer in Coupled Industrial-Scale Tundish of a Continuous Casting Material in Steel Production","authors":"J. A. Castro, B. A. Pereira, Roan Sampaio deSouza, E. M. Oliveira, I. Ferreira","doi":"10.5772/INTECHOPEN.75935","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.75935","url":null,"abstract":"This chapter describes the numerical simulations of a coupled industrial scale of the tundish and continuous casting process. The governing equations are presented, and the numerical procedure is discussed in a common framework. The coupled solutions are presented for the transient turbulent flows within the tundish, solidifying zone and extracting regions with the coupling phenomena of heat and mass transfer. The tundish region flow and refractory are calculated using the inlet and outlet boundary conditions in order to estimate the filling phenomena. The transitions and cooling zones for the thin slab continuous casting process are designed to account for the control of the solidified skin in order to avoid breakout. We compared the numerical predictions of the temperatures with industrial monitoring data for a reference case in order to verify the consistence of the model predictions. A parallel version of the numerical code is proposed aiming to improve the computation time keeping numerical accuracy.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128996992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-21DOI: 10.5772/INTECHOPEN.73501
M. Cadatal-Raduban, M. Pham, Luong Viet Mui, N. Hung, N. Sarukura
Transient cavity method used to generate ultrashort laser pulses in dye lasers is extended to a solid-state gain medium. Numerical simulations are performed to investigate the spectro-temporal evolution of broadband ultraviolet (UV) laser emission from Ce-doped LiCaAlF6 (Ce:LiCAF), which is represented as a system of two homogeneous broadened singlet states. By solving the rate equations extended to multiple wavelengths, the appropriate cavity length and Q-factor for optimal photon cavity decay time and pumping energy that will generate resonator transients is determined. Formation of resonator transients could generate picosecond UV laser pulses from a Ce:LiCAF crystal pumped by the fourth harmonics (266 nm) of a Nd:YAG laser. Numerical simulations indicate that a 1-mol% Ce-doped LiCAF crystal that is 1-mm long can generate a single picosecond pulse. This is accomplished by using a low Q (output coupler reflectivity of 10%), short cavity (cavity length of 2 mm) laser oscillator. Ultrashort pulses can also be generated using other rare earth-doped fluoride laser materials using this technique.
{"title":"Ultrashort Pulse Generation in Ce:LiCAF Ultraviolet Laser","authors":"M. Cadatal-Raduban, M. Pham, Luong Viet Mui, N. Hung, N. Sarukura","doi":"10.5772/INTECHOPEN.73501","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.73501","url":null,"abstract":"Transient cavity method used to generate ultrashort laser pulses in dye lasers is extended to a solid-state gain medium. Numerical simulations are performed to investigate the spectro-temporal evolution of broadband ultraviolet (UV) laser emission from Ce-doped LiCaAlF6 (Ce:LiCAF), which is represented as a system of two homogeneous broadened singlet states. By solving the rate equations extended to multiple wavelengths, the appropriate cavity length and Q-factor for optimal photon cavity decay time and pumping energy that will generate resonator transients is determined. Formation of resonator transients could generate picosecond UV laser pulses from a Ce:LiCAF crystal pumped by the fourth harmonics (266 nm) of a Nd:YAG laser. Numerical simulations indicate that a 1-mol% Ce-doped LiCAF crystal that is 1-mm long can generate a single picosecond pulse. This is accomplished by using a low Q (output coupler reflectivity of 10%), short cavity (cavity length of 2 mm) laser oscillator. Ultrashort pulses can also be generated using other rare earth-doped fluoride laser materials using this technique.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114570298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-06DOI: 10.5772/INTECHOPEN.72098
CH. V. K. N. S. N. Moorthy, V. Srinivas
The aero-thermodynamic design and performance of a compressor need to conquer many vital challenges like it is a gas-driven turbo-machinery component, involvement of extensive iterative process for the convergence of the design, enormous design complexity due to three-dimensional flow phenomena, and multiflow physics embedded within a dynamic state-of-the-art. In this chapter, a strong attempt is made to address the above-cited techni- cal issues to achieve an optimized design and performance of a centrifugal compressor with backward swept blade profile producing total pressure ratio of 5.4 with an ingested mass flow rate of 5.73 kg/s. A mean-line design methodology was implemented to configure sizing of the compressor. An optimum grid size was well validated by carrying out compu- tational analysis with three different mesh sizes within the same framework. Finally, a detailed three-dimensional numerical simulation was performed using Reynolds-averaged Navier-Stokes equations based on finite volume discretization method (RANS-FVDM) scheme. Consequently, the polytropic efficiency, total-to-total efficiency, stagnation pressure ratio at a fixed rotational speed, and the overall design and aero-thermodynamic performance of the centrifugal compressor are validated.
{"title":"Numerical Simulations of a High-Resolution RANS-FVDM Scheme for the Design of a Gas Turbine Centrifugal Compressor","authors":"CH. V. K. N. S. N. Moorthy, V. Srinivas","doi":"10.5772/INTECHOPEN.72098","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.72098","url":null,"abstract":"The aero-thermodynamic design and performance of a compressor need to conquer many vital challenges like it is a gas-driven turbo-machinery component, involvement of extensive iterative process for the convergence of the design, enormous design complexity due to three-dimensional flow phenomena, and multiflow physics embedded within a dynamic state-of-the-art. In this chapter, a strong attempt is made to address the above-cited techni- cal issues to achieve an optimized design and performance of a centrifugal compressor with backward swept blade profile producing total pressure ratio of 5.4 with an ingested mass flow rate of 5.73 kg/s. A mean-line design methodology was implemented to configure sizing of the compressor. An optimum grid size was well validated by carrying out compu- tational analysis with three different mesh sizes within the same framework. Finally, a detailed three-dimensional numerical simulation was performed using Reynolds-averaged Navier-Stokes equations based on finite volume discretization method (RANS-FVDM) scheme. Consequently, the polytropic efficiency, total-to-total efficiency, stagnation pressure ratio at a fixed rotational speed, and the overall design and aero-thermodynamic performance of the centrifugal compressor are validated.","PeriodicalId":103650,"journal":{"name":"Numerical Simulations in Engineering and Science","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130993591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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