Comparative Study on Ultimate Pullout Resistance Test and Theoretical Derivation of Flexible Pressurized Anchor with Numerical Simulation Result

2012 ◽  
Vol 268-270 ◽  
pp. 753-760
Author(s):  
Xuan Li Zhang ◽  
Wen Bin Wei
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Theoretical Derivation ◽  
Material Body ◽  
Pullout Resistance ◽  
Test Study ◽  
Simulation Calculation ◽  
Calculation Process ◽  
Calculation Results ◽  
Pressure Stress

The study on anchorage characteristics of flexible pressurized anchor should be along with theoretical analysis, numerical simulation and test study. Through comparing three calculation results, it is concluded that the theoretical analysis and numerical simulation can authenticate the correctness of calculation process each other; After considering the situation that friction coefficient changed with different contact pressure stress, the deviation of calculation of theory derivation and numerical simulation with experimental results significantly reduced; Anchor was simplified for anisotropic composite material body, which should be able to better reduce deviation among test, theoretical derivation and numerical simulation calculation.

Aerodynamic Characteristics Simulation Analysis of a Certain Type Changed Wing Drone Aircraft Based on CFD

2014 ◽  
Vol 644-650 ◽  
pp. 746-750
Author(s):  
De You Ma ◽  
Ming Xu ◽  
Zhao Tao Chen
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Type Model ◽  
Flight Performance ◽  
Flight Data ◽  
Simulation Calculation ◽  
Calculation Results ◽  
Conventional Type

This paper aims at the change of the whole machine aerodynamic characteristics after a certain conventional type drone aircraft changing plateau type large wings , using CFD technology to establish the nomal type and plateau type model, doing numerical simulation calculation of the whole machine's aerodynamic performance under the condition of no-load, using the simulation calculation results and combined with actual flight data, compared and evaluated the aerodynamic characteristics of the drone aircraft installed different airfoil, the results show that change plateau type large wings, obviously improve the lift-to-drag performance of the whole machine, increase the range of effective attack angle, and the little change of flight performance, scientific and feasible.

scholarly journals Influence of Hole Arrangement on the Section of Cavity Formed by Cutting Blast

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xianglong Li ◽  
Qiang Li ◽  
Jianguo Wang ◽  
Zichen Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Tensile Stress ◽  
Theoretical Calculation ◽  
Hole Diameter ◽  
Charge Hole ◽  
Horizontal Distance ◽  
Tunnel Excavation ◽  
Calculation Results ◽  
The Difference

In order to optimize the arrangement of cutting holes in tunnel blast in Dahongshan Copper Mine, theoretical analysis and numerical simulation were combined to preliminarily determine the diameter of the hollow hole and the distance between the charge hole and the hollow hole during cut blast, which was verified through the field blast test. The research results show that with the increase of the hole diameter, the peak compressive stress of rock surrounding the empty hole gradually decreases, and the peak tensile stress gradually increases, which is consistent with the calculation results; when the hole diameter is 10 cm, the two first blast holes are arranged horizontally and 30 cm from the empty hole, two second blast holes are arranged vertically and 40 cm away from the empty hole, and the four third blast holes are arranged at a horizontal distance of 45 cm and a vertical distance of 45 cm from the empty hole; the contour area in numerical simulation is the maximum. The difference in contour area, contour width, and contour and contour height between the measured value and the simulation result is 5.3%, 3.3%, and 3.4%, respectively, indicating that the combination of theoretical calculation and numerical simulation is suitable for prediction of cavity section after blast in tunnel excavation.

The Effect of Using Ramps with Trench Cylindrical Holes on Film Cooling Effectiveness

2015 ◽  
Vol 3 (2) ◽  
pp. 15-27
Author(s):  
Ahmed A. Imram ◽  
Humam K. Jalghef ◽  
Falah F. Hatem
Keyword(s):  
Numerical Simulation ◽  
Film Cooling ◽  
Air Injection ◽  
Baseline Model ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Hot Air ◽  
Test Study ◽  
Cylindrical Holes

     The effect of introducing ramp with a cylindrical slot hole on the film cooling effectiveness has been investigated experimentally and numerically. The film cooling effectiveness measurements are obtained experimentally. A test study was performed at a single mainstream with Reynolds number 76600 at three different coolant to mainstream blowing ratios 1.5, 2, and 3. Numerical simulation is introduced to primarily estimate the best ramp configurations and to predict the behavior of the transport phenomena in the region linked closely to the interaction between the coolant air injection and the hot air mainstram flow. The results showed that using ramps with trench cylindrical holes would enhanced the overall film cooling effectiveness by 83.33% compared with baseline model at blowing ratio of 1.5, also  the best overall flim cooling effectevness was obtained at blowing ratio of 2 while it is reduced at blowing ratio of 3.

scholarly journals Stress wave propagation in different number of fissured rock mass based on nonlinear analysis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoming Lou ◽  
Mingwu Sun ◽  
Jin Yu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Confining Pressure ◽  
Displacement Discontinuity ◽  
Stress Wave Propagation ◽  
Theoretical Derivation ◽  
Mechanics Model ◽  
Fissured Rock ◽  
Deep Rock ◽  
Theoretical Accuracy

AbstractThe fissures are ubiquitous in deep rock masses, and they are prone to instability and failure under dynamic loads. In order to study the propagation attenuation of dynamic stress waves in rock mass with different number of fractures under confining pressure, nonlinear theoretical analysis, indoor model test and numerical simulation are used respectively. The theoretical derivation is based on displacement discontinuity method and nonlinear fissure mechanics model named BB model. Using ABAQUS software to establish a numerical model to verify theoretical accuracy, and indoor model tests were carried out too. The research shows that the stress attenuation coefficient decreases with the increase of the number of fissures. The numerical simulation results and experimental results are basically consistent with the theoretical values, which verifies the rationality of the propagation equation.

scholarly journals Numerical Simulation of Intrachamber Processes in the Power Plant

2021 ◽  
Vol 11 (11) ◽  
pp. 4990
Author(s):  
Boris Benderskiy ◽  
Peter Frankovský ◽  
Alena Chernova
Keyword(s):  
Numerical Simulation ◽  
Power Plant ◽  
Flow Structure ◽  
Power Plants ◽  
Control Volume ◽  
Conjugate Problem ◽  
Topological Features ◽  
Gas Dynamic ◽  
Calculation Results ◽  
Volume Method

This paper considers the issues of numerical modeling of nonstationary spatial gas dynamics in the pre-nozzle volume of the combustion chamber of a power plant with a cylindrical slot channel at the power plant of the mass supply surface. The numerical simulation for spatial objects is based on the solution conjugate problem of heat exchange by the control volume method in the open integrated platform for numerical simulation of continuum mechanics problems (openFoam). The calculation results for gas-dynamic and thermal processes in the power plant with a four-nozzle cover are presented. The analysis of gas-dynamic parameters and thermal flows near the nozzle cover, depending on the canal geometry, is given. The topological features of the flow structure and thermophysical parameters near the nozzle cap were studied. For the first time, the transformation of topological features of the flow structure in the pre-nozzle volume at changes in the mass channel’s geometry is revealed, described, and analyzed. The dependence of the Nusselt number in the central point of stagnation on the time of the power plants operation is revealed.

Numerical Simulation of Cavitating Flow in a Francis Turbine

2008 ◽  
Author(s):  
Lingjiu Zhou ◽  
Zhengwei Wang ◽  
Yongyao Luo ◽  
Guangjie Peng
Keyword(s):  
Numerical Simulation ◽  
Transport Equation ◽  
Flow Rate ◽  
Suction Side ◽  
Cavitating Flow ◽  
Francis Turbine ◽  
Efficiency Change ◽  
Experiment Data ◽  
Calculation Results ◽  
Vapor Fraction

The 3-D unsteady Reynolds averaged Navier-tokes equations based on the pseudo-homogeneous flow theory and a vapor fraction transport-equation that accounts for non-condensable gas are solved to simulate cavitating flow in a Francis turbine. The calculation results agreed with experiment data reasonably. With the decrease of the Thoma number, the cavity first appears near the centre of the hub. At this stage the flow rate and the efficiency change little. Then the cavity near the centre of the hub grows thick and the cavities also appear on the blade suction side near outlet. With further reduce of the Thoma number the cavitation extends to the whole flow path, which causes flow rate and efficiency decrease rapidly.

Mechanical Property Analysis and Numerical Simulation of Honeycomb Sandwich Structure’s Core

2013 ◽  
Vol 631-632 ◽  
pp. 518-523 ◽  
Author(s):  
Xiang Li ◽  
Min You
Keyword(s):  
Numerical Simulation ◽  
Elastic Constants ◽  
Sandwich Structure ◽  
Optimization Design ◽  
Simulation Analysis ◽  
Finite Element Program ◽  
Honeycomb Sandwich ◽  
Calculation Results ◽  
Element Program ◽  
Typical Satellite

Owing to the lack of a good theory method to obtain the accurate equivalent elastic constants of hexagon honeycomb sandwich structure’s core, the paper analyzed mechanics performance of honeycomb sandwich structure’s core and deduced equivalent elastic constants of hexagon honeycomb sandwich structure’s core considering the wall plate expansion deformation’s effect of hexagonal cell. And also a typical satellite sandwich structure was chose as an application to analyze. The commercial finite element program ANSYS was employed to evaluate the mechanics property of hexagon honeycomb core. Numerical simulation analysis and theoretical calculation results show the formulas of equivalent elastic constants is correct and also research results of the paper provide theory basis for satellite cellular sandwich structure optimization design.

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.

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