Papers by Keyword: Fluid Simulation

Abstract: In this paper, we present an efficient approach based on Smoothed Particle Hydrodynamics (SPH) to simulate nearly incompressible fluids. The proposed method is an extension of the traditional SPH method designed for compressible fluids. We first introduce a new scheme for pressure evaluation to satisfy the incompressibility constraints. Then novel calculation methods for pressure force and viscosity force are discussed. Finally, the results demonstrate that our method is more capable of realistically simulating fluids with near-incompressibility than previous method.

Abstract: Differential pressure flow meter is a kind of very promising flow measuring instrument, the application range is very wide. But aiming at the defects that the mechanical structure of all kinds of existing flow meters is complex, the throttling way disturbs the fluid greatly and the stability of differential pressure signal is insufficient, a kind of new inside and outside tube differential pressure flow meter was designed.

Abstract: Based on the way of parametric design with SolidWorks, The 3D model of Whole welding type forged steel ball valve is established, Based on SolidWorks Flow Simulation, the simulation dynamic characteristics of ball valve was analyzed, By studying the ball hole edge radius R, Pointed out the direction for the design, through the simulation calculation of target parameters, analyzing the rationality of the structure of the sphere, to optimize the structure of ball valve, shorten the design cycle, and improve design quality. The simulation results are helpful to design improvement. The result indicates that the method is advanced and feasible. It has better practicability.

Abstract: When extrusion molding, the pressure fluctuations within the nose is the largest problem in the extruder production. In the present, we use mainly to change speed to adjust the pressure fluctuations, but knowledge is still relatively scarce on relation between the speed and pressure. By CFX fluid simulation of flow field distribution in extruder based on PVC production, we obtain the law of pressure with the change of speed, which provide guidance for the control of press inside the extruder.

Abstract: Based on the theory of gas-solid two-phase flow, abrasive flows in ceramic nozzles with different structures are simulated by FLUENT software and the outflow velocity of particles is compared. The results show: the abrasive outflow velocity of ceramic nozzle with cone angle is large than that of ceramic nozzle with through-hole structure, and the distribution of abrasive particles is more uniform for the ceramic nozzle with cone angle. The best entrance cone angle of ceramic nozzle is 10o30o, and the maximum abrasive outflow velocity of the ceramic nozzle with cone angle of 20o is 90.16 m/s. The simulation results have a good agreement with the experimental results.

Abstract: There is much research focusing on natural phenomena simulation in virtual reality and computer graphics. Liquid is chosen as our research object, because it is one of the most common natural phenomena. A particle-based modeling method for dynamic liquid simulation is presented in this paper. In our approach, accurate solutions for the Navier-Stokes equations are first accomplished in an Euler-based grid at each time step. This returns a velocity field calculated based on the pressure solved from a converted Poisson equation. Finally, particle movements are advected through this velocity field in order to simulate the dynamics of fluid volume. Experiment shows that visual effect which can satisfy users requirement is achieved by this method. This application has promising potentials in the areas of movie making, computer games, virtual construction and virtual simulation in medicine, etc.

Abstract: Hydrodynamic force is one of the important factors to be considered in the design of hydraulic valves. In this paper, mathematical formula of steady hydrodynamic force was deduced basing on non-circular opening spool valve structure and working principle. The simulations were carried out with software FLUENT at differential pressure, different valve port openings, and then the variation of the steady hydrodynamic force can be obtained. The results show that the direction of the steady hydrodynamic force is opposite to the movement of the valve spool and tends to close the valve port; the magnitude of the steady hydrodynamic force is proportional to the valve opening and differential pressure respectively.

Abstract: In order to study the effects of velocity distribution of ultrasonic gas flow meter based on wall roughness, , a full developed turbulence model is established based on the theory of prandtl mixing length and flow loss coefficent λ has been calculated by using Colebrook friction correlation formula after analyzing time interval difference measuring method of ultrasonic flow meter. Through Matlab calculating and simulating velocity distribution in different conditions of wall roughness about the model shows and through Fluent simulating, velocity vector and pressure distribution in smooth and rough tube have been compared and analyzed. The experimental results shows that quantification of velocity distribution based on wall roughness can been solved with the model, and the analysis results have certain instructive significance to the development of ultrasonic gas flow meter.

Abstract: Turbulence generator is a key part of head box of middle or high speed papermachine. It is used to make the fiber flow smooth and steady. This paper gives simulation researches of the flow status on one turbulent tube of combined-turbulence generator, result shows that there is an optimal rate between the square tube and its equivalent diameter for Round-Square turbulence generator, and the equivalent diameter is 6.5. This guides the design of turbulence generator significantly.