scholarly journals DEVELOPMENT OF STRONGLY COUPLED SIMULATION METHOD AND STUDY ON CALCULATION METHOD OF VIEW FACTOR : Study on transient simulation method for coupling three dimensional conduciton, convection and radiation (Part 1)

2003 ◽  
Vol 68 (565) ◽  
pp. 41-46
Author(s):  
Masashi IMANO ◽  
Takashi KURABUCHI ◽  
Motoyasu KAMATA
Keyword(s):  
Calculation Method ◽  
Three Dimensional ◽  
Simulation Method ◽  
Transient Simulation ◽  
View Factor ◽  
Coupled Simulation ◽  
Strongly Coupled ◽  
Factor Study

Transient Simulation of a Three-Dimensional Moving Downburst

2012 ◽  
Vol 446-449 ◽  
pp. 3875-3878
Author(s):  
Bai Feng Ji ◽  
Wei Lian Qu
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Wind Field ◽  
Three Dimensional ◽  
Simulation Method ◽  
Transient Simulation ◽  
Dynamics Simulation ◽  
Transmission Tower ◽  
Transient Wind

Thunderstorm microbursts, which are sources of extreme wind loadings in nature, have caused numerous structural failures, especially collapses of transmission tower around the world. Numerical simulation using computational fluid dynamics (CFD) has recently made significant progress in simulating downbursts. In this paper, transient simulation of a three-dimensional moving downburst was studied using computational fluid dynamics simulation method. Transient simulation of a three-dimensional moving downburst was conducted using time-filtered Reynolds Averaged Navier-Stokes (RANS) numerical simulation method. The three-dimensional transient wind field characteristics in a moving downburst were studied in detail. The results indicate that transient wind field characteristics in a moving downburst present quite different characteristics compared with stationary downburst at different heights and radial positions.

A Quasi-3D Calculation Method for Gas Turbine Combustor Liner Wall Cooling Techniques

1994 ◽  
Author(s):  
N. K. Rizk
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Calculation Method ◽  
Film Cooling ◽  
Radiation Flux ◽  
Three Dimensional ◽  
View Factor ◽  
Calculation Technique ◽  
Conventional Film

To obtain more accurate estimates of wall temperature of gas turbine combustors, it is essential to include the radiation flux contribution from the flame and hot gases into each wall segment. This step calls for the knowledge of the detailed three-dimensional combustor flow field in addition to an accurate means of defining a radiation view factor. In the present investigation, a quasi-three-dimensional calculation method is adopted to predict the wall temperature of a number of production combustors. The method utilizes the flow field parameters as given by the analytical code to evaluate the radiation and convection heat loading to the wall. It makes use of empirical expressions for overall effectiveness of different cooling schemes including conventional film cooling, extended surface convective/film cooling, impingement jets and transpiration systems such as Lamilloy*, effusion, and compliant matrix cooling. The calculation technique takes into account the fuel effects on wall temperature through their impact on the detailed flow field and radiation flux. The model validation involved comparing the calculations with the measured data of several combustors that used either film cooling devices or effusion hole schemes and operated on typical aviation fuels as well as special high density fuel types. An investigation of such effects as air distribution and the spray SMD on wall temperature was also conducted in the present effort.

scholarly journals PSCAD-MATLAB Coupled Simulation Method for Power Flow Optimization using Continuous Reactive Power Controllable Device

2021 ◽  
Vol 1754 (1) ◽  
pp. 012026
Author(s):  
Fan Yang ◽  
Kai Chen ◽  
Shaofeng Qian ◽  
JiangYang Zhan ◽  
Rui Yu ◽  
...  
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Simulation Method ◽  
Coupled Simulation ◽  
Flow Optimization

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

scholarly journals Prandtl Number in Classical Hard-Sphere and One-Component Plasma Fluids

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 821
Author(s):  
Sergey Khrapak ◽  
Alexey Khrapak
Keyword(s):  
Prandtl Number ◽  
Hard Sphere ◽  
Solid Phase ◽  
Freezing Point ◽  
Three Dimensional ◽  
Order Unity ◽  
Strongly Coupled ◽  
Dielectric Fluids ◽  
Weakly Coupled ◽  
Component Plasma

The Prandtl number is evaluated for the three-dimensional hard-sphere and one-component plasma fluids, from the dilute weakly coupled regime up to a dense strongly coupled regime near the fluid-solid phase transition. In both cases, numerical values of order unity are obtained. The Prandtl number increases on approaching the freezing point, where it reaches a quasi-universal value for simple dielectric fluids of about ≃1.7. Relations to two-dimensional fluids are briefly discussed.

scholarly journals Three-dimensional 𝒩 = 2 supersymmetric gauge theories and partition functions on Seifert manifolds: A review

2019 ◽  
Vol 34 (23) ◽  
pp. 1930011 ◽  
Author(s):  
Cyril Closset ◽  
Heeyeon Kim
Keyword(s):  
Correlation Functions ◽  
Gauge Theories ◽  
Three Dimensional ◽  
Partition Functions ◽  
Exact Results ◽  
Strongly Coupled ◽  
Seifert Manifolds ◽  
Recent Developments ◽  
Supersymmetric Gauge ◽  
Chern Simons

We give a pedagogical introduction to the study of supersymmetric partition functions of 3D [Formula: see text] supersymmetric Chern–Simons-matter theories (with an [Formula: see text]-symmetry) on half-BPS closed three-manifolds — including [Formula: see text], [Formula: see text], and any Seifert three-manifold. Three-dimensional gauge theories can flow to nontrivial fixed points in the infrared. In the presence of 3D [Formula: see text] supersymmetry, many exact results are known about the strongly-coupled infrared, due in good part to powerful localization techniques. We review some of these techniques and emphasize some more recent developments, which provide a simple and comprehensive formalism for the exact computation of half-BPS observables on closed three-manifolds (partition functions and correlation functions of line operators). Along the way, we also review simple examples of 3D infrared dualities. The computation of supersymmetric partition functions provides exceedingly precise tests of these dualities.

scholarly journals Study of the Effect of Centrifugal Force on Rotor Blade Icing Process

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengzhi Wang ◽  
Chunling Zhu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Force ◽  
Rotor Blade ◽  
Flow Direction ◽  
Three Dimensional ◽  
Simulation Method ◽  
Two Phase ◽  
Numerical Simulation Method ◽  
Calculation Results ◽  
Flow Field Characteristics

In view of the rotor icing problems, the influence of centrifugal force on rotor blade icing is investigated. A numerical simulation method of three-dimensional rotor blade icing is presented. Body-fitted grids around the rotor blade are generated using overlapping grid technology and rotor flow field characteristics are obtained by solving N-S equations. According to Eulerian two-phase flow, the droplet trajectories are calculated and droplet impingement characteristics are obtained. The mass and energy conservation equations of ice accretion model are established and a new calculation method of runback water mass based on shear stress and centrifugal force is proposed to simulate water flow and ice shape. The calculation results are compared with available experimental results in order to verify the correctness of the numerical simulation method. The influence of centrifugal force on rotor icing is calculated. The results show that the flow direction and distribution of liquid water on rotor surfaces change under the action of centrifugal force, which lead to the increasing of icing at the stagnation point and the decreasing of icing on both frozen limitations.

Thermo-mechanical coupling particle simulation of three-dimensional large-scale non-isothermal problems

2017 ◽  
Vol 34 (5) ◽  
pp. 1551-1571 ◽  
Author(s):  
Ming Xia
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Particle Simulation ◽  
Similarity Criteria ◽  
Particle Model ◽  
Length Scale ◽  
Content Type ◽  
Mechanical Coupling ◽  
Particle Simulation Method

Purpose The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale non-isothermal problems, so that a small 3D length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large 3D length-scale one. Design/methodology/approach The objective is achieved by following the scaling methodology proposed by Feng and Owen (2014). Findings After four basic physical quantities and their similarity-ratios are chosen, the derived quantities and its similarity-ratios can be derived from its dimensions. As the proposed comprehensive 3D upscale theory contains five similarity criteria, it reveals the intrinsic relationship between the particle-simulation solution obtained from a small 3D length-scale (e.g. a laboratory length-scale) model and that obtained from a large 3D length-scale (e.g. a geological length-scale) one. The scale invariance of the 3D interaction law in the thermo-mechanical coupled particle model is examined. The proposed 3D upscale theory is tested through two typical examples. Finally, a practical application example of 3D transient heat flow in a solid with constant heat flux is given to illustrate the performance of the proposed 3D upscale theory in the thermo-mechanical coupling particle simulation of 3D large-scale non-isothermal problems. Both the benchmark tests and application example are provided to demonstrate the correctness and usefulness of the proposed 3D upscale theory for simulating 3D non-isothermal problems using the particle simulation method. Originality/value The paper provides some important theoretical guidance to modeling 3D large-scale non-isothermal problems at both the engineering length-scale (i.e. the meter-scale) and the geological length-scale (i.e. the kilometer-scale) using the particle simulation method directly.

Calculation and Design Method Study of the Coil-Wound Heat Exchanger

2014 ◽  
Vol 1008-1009 ◽  
pp. 850-860 ◽  
Author(s):  
Zhou Wei Zhang ◽  
Jia Xing Xue ◽  
Ya Hong Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Design Method ◽  
Fluid Velocity ◽  
Exchange Process ◽  
Three Dimensional ◽  
Simulation Method ◽  
Physical Parameters ◽  
Numerical Result

A calculation method for counter-current type coil-wound heat exchanger is presented for heat exchange process. The numerical simulation method is applied to determine the basic physical parameters of wound bundles. By controlling the inlet fluid velocity varying in coil-wound heat exchanger to program and calculate the iterative process. The calculation data is analyzed by comparison of numerical result and the unit three dimensional pipe bundle model was built. Studies show that the introduction of numerical simulation can simplify the pipe winding process and accelerate the calculation and design of overall configuration in coil-wound heat exchanger. This method can be applied to the physical modeling and heat transfer calculation of pipe bundles in coil wound heat exchanger, program to calculate the complex heat transfer changing with velocity and other parameters, and optimize the overall design and calculation of spiral bundles.

Effects of Wheel-Shaft-Fluid Coupling and Local Wheel Deformations on the Global Behavior of Shaft Lines

2002 ◽  
Vol 124 (4) ◽  
pp. 953-957 ◽  
Author(s):  
D. Lornage ◽  
E. Chatelet ◽  
G. Jacquet-Richardet
Keyword(s):  
Three Dimensional ◽  
Fluid Film ◽  
Global Behavior ◽  
Three Dimensional Model ◽  
Fluid Films ◽  
Strongly Coupled ◽  
Proposed Model ◽  
Structural Deformations ◽  
Time Marching ◽  
Fluid Coupling

Rotating parts of turbomachines are generally studied using different uncoupled approaches. For example, the dynamic behavior of shafts and wheels are considered independently and the influence of the surrounding fluid is often taken into account in an approximate way. These approaches, while often sufficiently accurate, are questionable when wheel-shaft coupling is observed or when fluid elements are strongly coupled with local structural deformations (leakage flow between wheel and casing, fluid bearings mounted on a thin-walled shaft, etc.). The approach proposed is a step toward a global model of shaft lines. The whole flexible wheel-shaft assembly and the influence of specific fluid film elements are considered in a fully three-dimensional model. In this paper, the proposed model is first presented and then applied to a simple disk-shaft assembly coupled with a fluid film clustered between the disk and a rigid casing. The finite element method is used together with a modal reduction for the structural analysis. As thin fluid films are considered, the Reynolds equation is solved using finite differences in order to obtain the pressure field. Data are transferred between structural and fluid meshes using a general method based on an interfacing grid concept. The equations governing the whole system are solved within a time-marching procedure. The results obtained show significant influence of specific three-dimensional features such as disk-shaft coupling and local disk deformations on global behavior.

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