Modeling Under Hood Cooling Using a Coupled-Code Approach

2003 ◽  
Author(s):  
Gino Bella ◽  
Rossella Rotondi
Keyword(s):  
Computational Models ◽  
Optimal Solution ◽  
Computational Design ◽  
Industrial Applications ◽  
Computational Time ◽  
Simulation Techniques ◽  
Flow And Heat Transfer ◽  
Complex Simulation ◽  
Coupled Codes ◽  
Physical Phenomena

The need to shorten the development time for new engine and vehicles is leading to the increasing use of computational design and simulation methods in the automotive industry. In the last years 3D computational models have been used successfully in vehicle and engine development. It is clear that in this kind of simulation, the input complexity, the output data management and the computational time increase. On the other hand 3D simulations increase the details of the results and their link with the analyzed geometry. During a vehicle design several numerical techniques can be used (finite difference, finite volume, spectral methods, boundary elements, etc.) Often, in a complex simulation, that involves several different physical phenomena such as fluid flow and heat transfer only the use of different simulation techniques allows to obtain good results in a acceptable time. In several industrial applications the use of coupled codes, with different features (1D, 3D or different numerical schemes) could provide an optimal solution for the simulation approach. In this paper an example of a complex simulation of an Under Hood Cooling (UHC) of a vehicle is carried out using two different 3D codes with different numerical approaches with the objective to reduce the simulation time [1].

Structural Non-Linear Models and Simulation Techniques

2016 ◽  
pp. 540-584
Author(s):  
Jorge M. Delgado ◽  
Antonio Abel R. Henriques ◽  
Raimundo M. Delgado
Keyword(s):  
Computational Models ◽  
Linear Models ◽  
Civil Engineering ◽  
Numerical Models ◽  
Probabilistic Approach ◽  
Latin Hypercube Sampling ◽  
Computational Time ◽  
Rc Structures ◽  
Simulation Techniques ◽  
Non Linear

Advances in computer technology allow nowadays the use of powerful computational models to describe the non-linear structural behavior of reinforced concrete (RC) structures. However their utilization for structural analysis and design is not so easy to be combined with the partial safety factors criteria presented in civil engineering international codes. Trying to minimize this type of difficulties, it is proposed a method for safety verification of RC structures based on a probabilistic approach. This method consists in the application of non-linear structural numerical models and simulation methods. In order to reduce computational time consuming the Latin Hypercube sampling method was adopted, providing a constrained sampling scheme instead of general random sampling like Monte Carlo method. The proposed methodology permits to calculate the probability of failure of RC structures, to evaluate the accuracy of any design criteria and, in particular, the accuracy of simplified structural design rules, like those proposed in civil engineering codes.

scholarly journals REVIEW OF CFD SIMULATION OF OXY-COAL COMBUSTION FOR ELETRICAL POWER GENERATION: OPPORTUNITIES AND CHALLENGES

2016 ◽  
Vol 15 (2) ◽  
pp. 76
Author(s):  
F. S. Nascimento ◽  
M. A. R. Nascimento ◽  
C. J. R. Coronado ◽  
L. O. Rodrigues ◽  
J. A. Carvalho Jr ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Combustion ◽  
Cfd Simulation ◽  
Numerical Models ◽  
Cost Savings ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Simulation Techniques ◽  
Reduction Of Co2 ◽  
Physical Phenomena

The oxy-combustion has generated significant interested for reduction of CO2 emission when the fossil fuel is coal, due to simplification on the separation process of CO2 from the flue gas, it can be more easily stored in reservoir. The CFD numerical simulation techniques in oxy-coal combustion has the potential to contribute to designers in cost savings and reduced computational time; Furthermore, such techniques also provide a robust tool for better understanding and description of the aerothermodynamics processes involved, as well as, aiding the design of most efficient furnaces. However, to obtain representative results of the physical phenomena, the numerical models employed by CFD needs to be suitable for oxy-coal combustion. So, the aim of the paper is to carry out a review of the recent models that are being used for turbulence, combustion and pollutant emissions. Moreover, it is shown a comparison of different results obtained in the numerical simulation of oxy-coal combustion among new models, existing models and experiments. The analysis of the models and experiments shows that the challenges that are still being faced to obtain better accuracy of numerical simulation results. Improvements in the models for oxy-coal combustion can be seen like potential opportunities to investigate and optimize the process that occur in the combustion.

Investigation of Two-Phase Rimming Flow and Heat Transfer inside Rotational Paper Cylinder Dryers using Three Multiphase Computational Models

2021 ◽  
pp. 1-21
Author(s):  
Hamed Abdul Majeed ◽  
Victor Barboza Pereira ◽  
Ting Wang ◽  
Joseph V. D'Amico ◽  
Chris Kononchek
Keyword(s):  
Heat Transfer ◽  
Mixture Model ◽  
Computational Models ◽  
Flow Behavior ◽  
Paper Industry ◽  
Computational Time ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Vof Model ◽  
Five Phases

Abstract The paper industry uses rotating cylinder dryers that employ steam to heat the paper web moving over the cylinder outer walls. As steam condenses, the condensate is accumulated inside the dryers and evacuated using siphons. The form of condensate motion occurring inside a rotating dryer consisting of three modes: puddling, cascading or rimming. To help improve the drying performance, it is important to understand the fundamental thermal-fluid physics in the rotational dryer. Thus, the objectives of this study are (a) to investigate the dynamic two-phase flow and heat transfer behavior inside the rotational dryer at different rotational speeds; (b) to employ three different multiphase computational models, the Volume of Fluid (VOF) model, the Mixture model, and the Eulerian-Eulerian (E-E) model, and compare their results. The results show that the E-E model better captures the physics of condensate behavior inside the dryer. It also predicts very well the rimming speed in comparison with the empirical correlation although it takes longer computational time than the VOF model. The mixture model doesn't adequately capture the cascade and rimming physics due to excessive liquid dispersion. Based on the results, the categorization of the thermal-flow behavior of the liquid layer is expanded from the traditional three phases to five phases: puddling, transitional cascading, cascading, transitional rimming, and steady rimming. Generally, the heat transfer increases during the initial puddling period, followed by oscillatory attenuation during the cascade period, and finally reaches the steady state after rimming is achieved.

Investigation of Two-Phase Flow and Heat Transfer Inside Rotational Paper Dryers Using Three Different Multiphase Computational Models

2020 ◽  
Author(s):  
Hamed Majeed ◽  
Victor Barboza Pereira ◽  
Ting Wang ◽  
Joseph V. D’Amico ◽  
Chris Kononchek
Keyword(s):  
Heat Transfer ◽  
Mixture Model ◽  
Liquid Layer ◽  
Computational Models ◽  
Two Phase Flow ◽  
Computational Time ◽  
Phase Flow ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Vof Model

Abstract The paper industry uses cylinder dryers that employ steam to heat the paper web moving over the cylinder outer walls. As steam condenses, the condensate is accumulated inside the cylinder dryers. The condensate is evacuated using either stationary or rotary siphons. The form of condensate motion occurring inside the cylinder can be puddling, cascading or rimming depending on the size of the cylinder dryer, the rotating speed, the amount of condensate, and the surface finish of the cylinder dryer inner wall with or without ribs or grooves. The behavior of the condensate inside the cylinder dryers affects the heat transfer through the cylinder wall, the torque and power requirements of the dryer, and the performance of the condensate evacuation via siphons. To help improve the drying performance, it is important to understand the fundamental thermal-fluid physics in the rotational dryer. Thus, the objectives of this study are (a) to investigate the dynamic two-phase flow and heat transfer behavior inside the rotational paper dryer at different rotational speeds; (b) to employ three different multiphase computational models, the Volume of Fluid (VOF) model, the Mixture model, and the Eulerian-Eulerian (E-E) model, and compare their results. The results show that the E-E model better captures the physics of condensate behavior inside the dryer. It also predicts very well the rimming speed in comparison with the empirical correlation although it takes longer computational time than the VOF model. The mixture model doesn’t adequately capture the cascade and rimming physics due to excessive liquid dispersion. Based on the results, the categorization of the thermal-flow behavior of the liquid layer is expanded from the traditional three phases to five phases: puddling, transitional cascading, cascading, transitional rimming, and steady rimming. A detailed analysis of the rotating liquid layer behavior and its corresponding wall heat transfer passing through each phase is presented. Generally, the heat transfer increases during the initial puddling period, followed by oscillatory attenuation during the cascade period, finally reaches steady state after rimming is achieved.

scholarly journals Structural Non-Linear Models and Simulation Techniques

2016 ◽  
pp. 369-406
Author(s):  
Jorge M. Delgado ◽  
Antonio Abel R. Henriques ◽  
Raimundo M. Delgado
Keyword(s):  
Computational Models ◽  
Linear Models ◽  
Civil Engineering ◽  
Numerical Models ◽  
Probabilistic Approach ◽  
Latin Hypercube Sampling ◽  
Computational Time ◽  
Rc Structures ◽  
Simulation Techniques ◽  
Non Linear

Advances in computer technology allow nowadays the use of powerful computational models to describe the non-linear structural behavior of reinforced concrete (RC) structures. However their utilization for structural analysis and design is not so easy to be combined with the partial safety factors criteria presented in civil engineering international codes. Trying to minimize this type of difficulties, it is proposed a method for safety verification of RC structures based on a probabilistic approach. This method consists in the application of non-linear structural numerical models and simulation methods. In order to reduce computational time consuming the Latin Hypercube sampling method was adopted, providing a constrained sampling scheme instead of general random sampling like Monte Carlo method. The proposed methodology permits to calculate the probability of failure of RC structures, to evaluate the accuracy of any design criteria and, in particular, the accuracy of simplified structural design rules, like those proposed in civil engineering codes.

A fast and accurate solution to optimal design of eddy-current PMCs with standard disc type

2021 ◽  
pp. 1-19
Author(s):  
Zheng rong Xia ◽  
Yong chen Pei ◽  
Dong xu Wang ◽  
Shun Wang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Optimal Solution ◽  
Industrial Applications ◽  
Accurate Solution ◽  
Parameter Determination ◽  
Experimental Investigations ◽  
Fe Model ◽  
Contribution Rate ◽  
Standard Disc

Although permanent magnet couplings (PMCs) have been under research for many years and have found successful industrial applications, this is still a technology under development. Accurate parameter determination is of significance for performance analysis and critical decisions on PMC design. However, the determination can often lead to an unacceptable increase in computation, especially when finite elements (FE) are used. The study aims to develop an FE model that is used for the structural design of a standard-disc type PMC for optimal torque. For the quick and accurate design, an integration optimal solution of the response surface methodology (RSM) and the Taguchi’s method was proposed. To verify the simulation, a series of experimental investigations were conducted on a self-developed testing platform. Furthermore, for a minimum set of FE analyses (FEA), a quantitative indicator called contribution rate, which can reflect effect level of structure parameters on the torque, was given based on the Taguchi method. Apart from this, the orthogonal matrix was used for the reduction of the FE calculation. Based on the contribution rate, the response surface methodology was adopted for the optimal torque determination with no increase in the PM volume. According to the optimization results, a fitting formula, which considers the contribution rates of the optimization variables, was presented. The results suggest that the FE simulations agree very well with the experiments, and the fitting formula can be used in the PMC design.

AFM-Based Nanoindentation Process: A Comparative Study

2012 ◽  
Author(s):  
Rapeepan Promyoo ◽  
Hazim El-Mounayri ◽  
Kody Varahramyan
Keyword(s):  
Md Simulation ◽  
Computational Models ◽  
Surface Deformation ◽  
Experimental Results ◽  
Computational Time ◽  
Machined Surface ◽  
Indentation Force ◽  
Subsurface Deformation ◽  
Different Types ◽  
Copper Aluminum

Atomic force microscopy (AFM) has been widely used for nanomachining and fabrication of micro/nanodevices. This paper describes the development and validation of computational models for AFM-based nanomachining. Molecular Dynamics (MD) technique is used to model and simulate mechanical indentation at the nanoscale for different types of materials, including gold, copper, aluminum, and silicon. The simulation allows for the prediction of indentation forces at the interface between an indenter and a substrate. The effects of tip materials on machined surface are investigated. The material deformation and indentation geometry are extracted based on the final locations of the atoms, which have been displaced by the rigid tool. In addition to the modeling, an AFM was used to conduct actual indentation at the nanoscale, and provide measurements to which the MD simulation predictions can be compared. The MD simulation results show that surface and subsurface deformation found in the case of gold, copper and aluminum have the same pattern. However, aluminum has more surface deformation than other materials. Two different types of indenter tips including diamond and silicon tips were used in the model. More surface and subsurface deformation can be observed for the case of nanoindentation with diamond tip. The indentation forces at various depths of indentation were obtained. It can be concluded that indentation force increases as depth of indentation increases. Due to limitations on computational time, the quantitative values of the indentation force obtained from MD simulation are not comparable to the experimental results. However, the increasing trends of indentation force are the same for both simulation and experimental results.

scholarly journals UPWARD FLOW AND HEAT TRANSFER AROUND TWO HEATED CIRCULAR CYLINDERS IN SQUARE DUCT UNDER AIDING THERMAL BUOYANCY

2020 ◽  
Vol 14 (1) ◽  
pp. 113-123
Author(s):  
H. Laidoudi
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Circular Cylinders ◽  
Upward Flow ◽  
Square Duct ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Ansys Cfx ◽  
Commercial Code ◽  
Physical Phenomena

This paper presents a numerical investigation of mixed convection heat transfer around a pair of identical circular cylinders placed in side-by-side arrangement inside a square cavity of single inlet and outlet ports. The investigation provided the analysis of gradual effect of aiding thermal buoyancy on upward flow around cylinders and its effect on heat transfer rate. For that purpose, the governing equations involving continuity, momentum and energy are solved using the commercial code ANSYS-CFX. The distance between cylinders is fixed with half-length of cavity. The simulation is assumed to be in laminar, steady, incompressible flow within range of following conditions: Re = 1 to 40, Ri = 0 to 1 at Pr = 0.71. The main obtained results are shown in the form of streamline and isotherm contours in order to interpret the physical phenomena of flow and heat transfer. The average Nusselt number is also computed and presented. It was found that increase in Reynolds number and/or Richardson number increases the heat transfer. Also, aiding thermal buoyancy creates new form of counter-rotating zones between cylinders.

Sign in / Sign up

Export Citation Format

Share Document