New Approach For Simulation Research Articles

A new approach for simulating D-T fusion interaction using the Geant4 toolkit

In this study, the Geant4 toolkit is utilized to present a new approach for simulation of the D-T interaction. The neutron production cross-section and the energy/angle distribution of neutrons produced as the D-T data libraries are incorporated in the Geant4, and their performance is evaluated. The spectra shape of the produced neutrons of the D-T interaction simulated by the Geant4 show good agreement compared to the results of the comparative codes (i.e. MCUNED, ENEA-JSI, and DDT). However, some differences are observed, especially, in angular range of 90–95 degrees. The reason for these differences as well as the results of the proposed approach in comparison with the results of the benchmark experiments as the next study are under consideration.

A diffuse interface IBM for compressible flows with Neumann boundary condition

The recently proposed boundary condition-enforced immersed boundary-gas kinetic flux solver (IB-GKFS) is a new approach for simulation of compressible flows with curved and moving boundaries. In the previous application of IB-GKFS, only the Dirichlet boundary condition is considered, which cannot be applied directly to the Neumann boundary condition. In this paper, an auxiliary layer of Lagrangian points is introduced to tackle Neumann boundary condition. Two test cases, including flow around a circular cylinder and flow around a NACA0012 airfoil, are carried out for validation. The results obtained by the present scheme are compared with the reference data available in the literature. Good agreements are achieved, which indicate that the developed method can effectively simulate the compressible flow with Neumann boundary condition.

A new approach in simulation of soil-structure interaction problems including damper effects

In this paper, numerical simulation of the issues related to soil-structure interaction (SSI) in the structures equipped with prestressed damping device (PDD) is presented. More specifically, this research examines the impacts of dampers on the interaction between the soil and the structure, considering a variety of conditions, including the effects of the soil boundaries simulated by infinite elements. Comparative analysis of the results with different disposition of the dampers is made using ANSYS nonlinear platform. It could be observed from the results of the numerical analysis that regarding the impact of dampers in the structure on SSI, the selection of the damper type has a significant role.

A new approach in simulation of soil-structure interaction problems including damper effects

A new approach in simulation of soil-structure interaction problems including damper effects

New Approach to Cogging Torque Simulation Using Numerical Functions

This paper presents a new approach for simulation of the cogging torque in a permanent-magnet (PM) machine. The method exploits the numerical functions for modeling the magnetic circuit of the machine. This paper introduces two improved functions to model the PMs and the air-gap permeance, aiming to compute the cogging torque in the PM machine. The first function states the magnetomotive-force drop on the machine air gap with respect to the angular position. The other function, named permeance function, models the air-gap permeance accurately, taking into account the stator saliency due to the teeth. The described procedure has been tested on a prototype PM machine.

New approach for simulation of large cluster impact using smoothed particle hydrodynamics method

Using large‐scale atomistic simulations, it has been shown that the macroscopic cratering behavior emerges for projectile impacts on Au at projectile sizes between 1000 and 10 000 Au atoms at impact velocities comparable to typical meteoroid velocities. This indicates that the continuum model‐like fluid can be a possible candidate for the physical model of large cluster sputtering. Smoothed particle hydrodynamics (SPH) is a mesh‐free particle method for obtaining approximate numerical solutions of the equations of fluid dynamics by replacing the fluid with a set of particles. In this work, SPH has been introduced for the first time as an alternative but macroscopic thus quick method for the computer simulation of large cluster impact. It has been demonstrated that cratering process can be observed at the impact simulation of water cluster on water target. The SPH simulation can be applied after improvements in physical models and algorithms to investigate the sputtering effect on solid target using water cluster primary ion beams. Copyright © 2014 John Wiley & Sons, Ltd.

A new approach for simulation of non-Gaussian processes

To realise the significant non-Gaussian features of the wind pressure acting on structures, such as high-rise buildings and roof structures, a new simulation approach is proposed for generating sample functions of multivariate stationary non-Gaussian processes. A standard cubic polynomial is proposed to represent the translation of a Gaussian process to a non-Gaussian wind pressure process. Then a set of non-linear equations is derived to determine the parameters of the polynomial. The relation for translation of correlation functions is obtained based on the properties of the Gaussian stochastic vector. Also, the weighted amplitude wave superposition method is employed to generate the underlying Gaussian processes. Further, the proposed new approach is demonstrated by simulation of the non-Gaussian wind pressure field acting on a large-span stadium roof. The numerical results show that the proposed approach is quite accurate and efficient. Hence the method is advantageous for wind pressure field simulation of structures with a large number of nodes.

A Novel Method for Onsite Commissioning of Wide-Area Protection

The wide-area protection technology is considered to apply in construction of smart grid, which offers new challenge to verifying work for secondary system. This paper describes a new method for onsite commissioning of wide-area power grid. It can accomplish coordination tests for protection devices in different areas based on numerical simulation and wireless commutation technology. Because structure of power grid is too complex to calculate results of electromagnetic transient efficiently. A new approach of simulation is shown in the paper, which uses FDNE circuit to replace external system. And an example of test is offered. The simulation result indicates that electromagnetic transient computation with FDNE can be satisfied with debug work for occurrence chains in smart grid.

A New Approach for Simulation of Annular Two-Phase Flow Considering the Four Involved Mass Transfer Mechanisms (Annalytical Concept)

Removed due to author request.

Optimization Approach for Continuous Catalytic Regenerative Reformer Processes

The new approach for simulation and optimization of a continuous catalytic regenerative (CCR) reformer process is proposed. Typical CCR reforming processes consist of three to four reactors with recycle. The reaction patterns and reactors are typically modeled using a system of partial differential equations (PDEs). The numerical simulation solution of the entire model for a process system consisting of multiple reaction zones with recycle is extremely time-consuming and, thus, impractical in optimization studies. That is why we proposed a more efficient simulation and optimization scheme based on quasi-steady-state assumptions. We define criteria for reactor fragmentation to avoid the introduction of large errors in the quasi-steady-state calculations. The optimization problem is formulated with the objective of minimizing fuel consumption. The employed objective function constitutes a combined measure for economic and environmental performance. It is shown that the proposed approach identifies considerable improvements for the process.

An approach to simulate cold roll‐forging of turbo‐engine thin compressor blade

PurposeStudying manufacturing process of compressor blade can reduce the production cost and time in aircraft turbo‐engine industries. In the cold roll‐forging of thin compressor blades, the elastic behavior of machine structure and rolls is considerable due to the higher volume of roll separating force. Owing to this kind of elastic deformation during rolling, the adjusted gap between the rolling dies is increased and this causes unexpected flow of material, shape and thickness. The purpose of this paper is to present a new approach for simulation of cold rolling of thin blades and studying the effect of elastic behavior of the machine structure as well as rolls deflection on the material flow and roll separating force.Design/methodology/approachIn this paper, the process has been investigated using experimental test and simulation by introducing a new approach in a decision‐making flowchart. Instead of simulating of the entire system structure, a couple of virtual deformable rolls are suggested. The specifications of these rolls are selected to behave elastically during rolling same as whole roll stand. In addition, the thickness values are compared in both experiment and simulation. Also, the roll separating force is compared with and without using this approach.FindingsA decision‐making algorithm has been presented that can be used to study the process. This finding provides the basis to investigate the effect of elastic deformation of machine structure and rolls on dimensional accuracy and roll force.Originality/valueResult of this work can promote the position of simulation of the thin rolled sections to an extent more compatible with reality. For instance, the amount of increased gap between two dies during rolling can be estimated accurately. Also the influence of this gap on final blade thickness and the roll force and on the roll torque can be investigated by this approach.

Upscaling of the permeability by multiscale wavelet transformations and simulation of multiphase flows in heterogeneous porous media

We describe a new approach for simulation of multiphase flows through heterogeneous porous media, such as oil reservoirs. The method, which is based on the wavelet transformation of the spatial distribution of the single-phase permeabilities, incorporates in the upscaled computational grid all the relevant data on the permeability, porosity, and other important properties of a porous medium at all the length scales. The upscaling method generates a nonuniform computational grid which preserves the resolved structure of the geological model in the near-well zones as well as in the high-permeability sectors and upscales the rest of the geological model. As such, the method is a multiscale one that preserves all the important information across all the relevant length scales. Using a robust front-detection method which eliminates the numerical dispersion by a high-order total variation diminishing method (suitable for the type of nonuniform upscaled grid that we generate), we obtain highly accurate results with a greatly reduced computational cost. The speed-up in the computations is up to over three orders of magnitude, depending on the degree of heterogeneity of the model. To demonstrate the accuracy and efficiency of our methods, five distinct models (including one with fractures) of heterogeneous porous media are considered, and two-phase flows in the models are studied, with and without the capillary pressure.

Radiation Induced Spent Nuclear Fuel Dissolution under Deep Repository Conditions

The dynamics of spent nuclear fuel dissolution in groundwater is an important part of the safety assessment of a deep geological repository for high level nuclear waste. In this paperwe discussthe most important elementary processes and parameters involved in radiation induced oxidative dissolution of spent nuclear fuel. Based on these processes, we also present a new approach for simulation of spent nuclear fuel dissolution under deep repository conditions. This approach accounts for the effects of fuel age, burn up, noble metal nanoparticle contents, aqueous H2 and HCO3- concentration, water chemistry, and combinations thereof. The results clearly indicate that solutes consuming H202 and combined effects of noble metal nanoparticles and H2 have significant impact on the rate of spent nuclear fuel dissolution. Using data from the two possible repository sites in Sweden, we have employed the new approach to estimate the maximum rate of spent nuclear fuel dissolution. This estimate indicates that H2 produced from radiolysis of groundwater alone will be sufficient to inhibit the dissolution completely for spent nuclear fuel older than 100 years.

Microwave Heating: A New Approach of Simulation and Validation

AbstractCurrently the distribution of microwave processes in industrial applications is sparsely spread. Reasons for this are, in particular, the inhomogeneous heating patterns and the lack of optimization potential, due to the lack of possibilities for simulation of coupled electromagnetic and thermal processes. In this work two commercial software packages have therefore been coupled to simulate local and time specified temperature distributions of microwave treated samples. The results are validated by the sophisticated magnetic resonance imaging (MRI) technique, in order to avoid the problems of measuring temperature distributions in microwave fields. This method of measurement is non‐invasive, shows high 3D spatial and time resolutions, and does not influence the electromagnetic field.

Spatial System Dynamics: New Approach for Simulation of Water Resources Systems

A new approach called spatial system dynamics (SSD) is presented to model feedback based dynamic processes in time and space. This approach is grounded in control theory for distributed parameter systems. System dynamics and geographic information system (GIS) are coupled to develop this modeling approach. The SSD modeling approach offers a single modeling framework for developing conceptually different models. It also provides the much-needed capability to model feedback based complex dynamic processes in time and space while giving insight into the interactions among different components of the system. The proposed approach is superior to existing techniques for dynamic modeling such as cellular automata and GIS and addresses most of the limitations present in these approaches. The SSD approach can be used to model a variety of physical and natural processes where the main interest is the space.time interaction, e.g., environmental/water resources processes, natural resources management, climate change, and disaster management. The applicability of the proposed approach is demonstrated with an application to flood management in the Red River basin in Manitoba, Canada.

Simulation of the microdisc problem in spherical co-ordinates. Application to electrogenerated chemiluminescence

In this paper, we demonstrate a new approach for simulation of the 2D microdisc problem in spherical co-ordinates and apply it to the solution of the non-steady-state electrogenerated chemiluminescence (ECL) problem at a microdisc electrode.

Improved simulation for strongly coupled micro-electro-mechanical systems: resonant vacuum sensor optimization

This paper describes a new approach for simulation and optimization of micro-electro-mechanical systems (MEMS) with strongly physical coupled behaviour. By the use of commercial analysis tools only, without any specific add-ons, MEMS simulation can be carried out to the end of system optimization. The combination of general purpose finite-elements analysis with multi-physics system simulation is successfully demonstrated, here by the example of a resonant total pressure sensor system.

A computer model for relating powder density to composition, employing simulations of dense random packings of monosized and bimodal spherical particles

This paper describes a model for relating powder composition to resultant density, which employs a new approach for simulation of the random dense packing of spherical particles. The powders are modelled as assemblies of spherical particles which are either all of one size, or a mixture of two sizes (categorised as monosized and bimodal packings, respectively). Random dense packing is the usual type of arrangement for metal powders, consisting of spherical particles above around 100 μm diameter (below this size friction can be dominant and vibration may be required for attainment of the powder `tap density'). This type of packing can be regarded as the result of gravitational forces which act on the spheres, moving them so that gaps are filled, with the assembly reaching a state of minimum potential energy. This movement is simulated here by an algorithm employing a large number of randomly generated movements, which have the effect of moving the spheres towards a central position. The resulting simulation was found to predict a fractional density (fd) of 0.635 for a random dense packing of spheres, which can be compared to the widely accepted value of 0.637. A correlation factor of 0.989 was obtained when comparing simulated and experimental packing densities for bimodal mixtures of spherical bronze particles. The model has been developed for application to the powder metallurgy (PM) manufacturing process, where it can be used to generate recommendations for particle sizes and proportions by mass, required for production of metal powders with specified densities.

A New Approach for Simulation of Cyclic Steam Stimulation Above Fracture Pressure by Modifying a Thermal Simulator

SUMMARY A fracture propagation model that includes fracture propagation kinematics and heat transfer between the fracture and the reservoir was developed by modifying an existing thermal simulator. The induced fracture was assumed to be highly conductive, and fracture storage was neglected. The model was applied to simulate cyclic steam stimulation processes for a typical heavy oil reservoir. In single-well simulation, a lag time between the beginning of the injection and the initiation of the fracture is predicted. This lag time increases with the cycle number while the maximum fracture length decreases with the cycle number. The fracture characteristics in multi-well pattern simulation are drastically different from the single-well case because of well interactions.