Numerical Simulation Of Flow Field Research Articles

Optimal design and performance analysis of an external circulation un-contact rotor pump

It's difficult to calculate the flow pulsation and efficiency of an un-contact rotor pump as there's a gap between the two rotors and internal leakage exists during the operation process. We analyze the primary cause that affects the volumetric efficiency of external circulation un-contact rotor pumps and discuss its gap leakage mechanisms. We establish the pump's 3d model, by using the calculation method and physical model provided from FLUENT software, and moving mesh grid and UDF technology are adopted in the unsteady flow field numerical simulation of the pump. Two rotors were set as rotating entities with fixed rotational speeds, while the boundary of the flow field calculation area changed as the rotors rotated, picking up each iterative step of the two rotors by the size of the moment and the outlet velocity through the function, and depositing them into the text file. The relationship between the two rotors' gap quantity, the rotor and the pump body's gap quantity, the transient flow characteristics and the pressure distribution of the pump's body were studied. The calculation results show that pump efficiency is the highest when the two rotors' minimum gap quantity is 0.17 millimetre, the rotor and the pump body's minimum axial gap quantity is 0.1 millimetre.

The 3D Numerical Simulation of Flow Field on Y-Shape Flaring Gate Piers Combined with Stepped Spillway

The energy dissipater of stepped spillway combined with flaring gate pier is widely used in china's hydraulic engineering. The finite volume method is applied to discrete analysis, with the RNG turbulence model and VOF model of water vapor two-phase, iterative solution of geometry reconstruction format unsteady flow to generate free surface. Adopting structured grid for geometric shape, numerically simulated the water vapor two-phase flow from the reservoir to stilling basin. The parabolic water-vapor interface , overall flow pattern, water wings, section depth and other hydraulic characteristics was produced by simulating the three-dimensional flow field.Compared the simulated results of water depth, flow velocity in stilling pool, the board pressure with experiment data, the average error is: the left side depth of 3 # table hole of 7.1%, and the right of 7.4%; the underside flow velocity of 3 # table hole of 5%;1 # table hole stilling pool board pressure of 7.6%,3 # table hole stilling pool board pressure of 6.6%.

Flow Field Numerical Simulation Analysis of Five Wing Horizontal Wave Turbine Power Plant with Different Blade Angles

Used FLUENT software to simulate the flow distribution of a certain horizontal turbine with its blade angle changed from 25 ° to-35 °.The simulation results show the flow field changes with a period which was a fifth to the turbine rotational period. When the blade heads deflected laterally, the high flow velocity appeared near rear back turbine blades, or it appeared near the facing flow blades which were in the front lower part of the turbine. Besides, for blade angle deflected inside models, a stable annular velocity vector vortex gradually emerged around turbine as blade angle increased. The maximum velocity of flow field increased firstly and then stayed stable as blade angle changed. The flow distribution results fully confirmed that the reasonable optimization to the blade angle of the turbine can help the turbine achieve a more effective rotation and improve the flow distribution.

The Study on Cavitation Phenomena of Zoom Nozzle Based on Orthogonal Experimental and Spraying Mechanics

Abstract: The simulation model of zoom nozzle was established in this article.The numerical simulation of flow field in the zoom nozzle was completed with the Fluent software and based on orthogonal experimental method the structure size optimization of the nozzle was completed too.The results showed that the cavitation phenomenon is easy to form near the transition area of the cylindrical section and expansion section of the nozzle.Using orthogonal experimental method,we can achieve structure size optimization of the nozzle from reducing cavitation rate and increase the distance that emergence point of maximum cavitation rate with the cylindrical section of nozzle.

Flow Field Numerical Simulation of Straight Line Conjugate Internal Meshing Gear Pump

In the designing of the straight line conjugate internal meshing gear pump, it is very important for us to analyze its flow field performance. In this paper, FLUEN is utilized to analyze its flow field which bases on moving grid computing ,the paper can get factors that structure impacts on performance. The work provides reference and a certain theory foundation for optimization of the gear pump and straight line conjugate internal meshing gear pump will be widely used in engineering machinery.

An arbitrary Lagrangian–Eulerian formulation for solving moving boundary problems with large displacements and rotations

An Arbitrary Lagrangian–Eulerian (ALE) formulation based on the unstructured finite volume method is proposed for solving moving boundary problems with large displacements and rotations. The numerical method is based on the side-centered arrangement of the primitive variables that does not require any ad-hoc modifications in order to enhance pressure coupling. The continuity equation is satisfied within each element at machine precision and the summation of the continuity equations can be exactly reduced to the domain boundary, which is important for the global mass conservation. A special attention is given to construct an ALE algorithm obeying the discrete geometric conservation law (DGCL). The mesh deformation algorithm is based on the indirect Radial Basis Function (RBF) algorithm at each time level while avoiding remeshing in order to enhance numerical robustness. For the parallel solution of resulting large-scale algebraic equations in a fully coupled form, a matrix factorization is introduced similar to that of the projection method for the whole system and the parallel algebraic multigrid solver BoomerAMG is used for the scaled discrete Laplacian provided by the HYPRE library which we access through the PETSc library. The present numerical algorithm is initially validated for the decaying Taylor–Green vortex flow, the flow past an oscillating circular cylinder in a channel and the flow induced by an oscillating sphere in a cubic cavity. Then the numerical algorithm is applied to the numerical simulation of flow field around a pair of flapping Drosophila wings in hover flight. The time variation of the Eulerian coherent structures in the near wake is shown along with the aerodynamic loads.

Flow Field Numerical Simulation and Performance Study of Two-Stage Superheated Electrical Steam Trap

In order to promote the localization of critical valve in ultra-supercritical thermal power generating unit, a two-stage superheated electrical steam trap was designed and developed. Its structure and operation principle was introduced. Three-dimensional numerical simulation of the internal turbulent fluid field was performed by using Fluent of computational fluid dynamics software. The results show that the superposed design of associated reaction with multiaperture equalizer and guide sleeve was adopted in the two-stage superheated steam trap. The internal flow field become more uniform, local maximum velocity reached 37.2m/s. The brush erosion of valve seat is reduced and the service life is increased. Success rate of the first sample's trial-manufacture is greatly improved by using CFD simulation experiment in the process of design. Development cycle is shortened and the cost is reduced, which can provide a reference for two-stage superheated steam trap design.

Numerical Simulation of Flow Field of Inflation Pressure for Large Complex Sulfide Mineral of Low-Tin Flotation Machine

For flotation characteristics of complex sulfide mineral of low-tin in Guangxi Dachang mine, fluid dynamics software FLUENT was applied to simulate the turbulence intensity of slurry fluid in flotation machine at different inflation pressures. The effect of flow field characteristics was gotten for flotation machine. Simulation results show that the best inflation pressure was 120000 Pa.

Numerical simulation of flow field and optimization for well test separator in platform offshore

In order to meet the requirements of the well test separator, cyclone，the effective separation of gas and liquid component, was added. According to the role of the various components, the numerical simulation was simplified as single phase or two phase, which carried out by Fluent software with the appropriate boundary conditions and mixture model to optimize internal components. Then the simulation of the whole separator was carried out. Through numerical simulation and optimization, the optimal structure of the components could be obtained, which can effectively increase the separation efficiency and meet the requirements of the oil in water <5%, water containing oil <5%, gas containing liquid <5%.

Study on the Method for CFX Numerical Simulation of Flow Field in Screw Conveyer of Sand Fracturing Blender

Screw conveyer is an important component of sand fracturing blender.seamless Link of Pro/e and CFX through ANSYS Workbench. Numerical simulation of water flow over the screw conveyer using Realizable k-ε turbulence model. From the stress nephogram, velocity nephogram, Velocity vector pofile and micro swirl field pattern, it is seems that the test results can work well under the actual operation condition of field application. This paper also focuses on exploring the method of CFX software simulation when it is used to calculate the internal flow field of the screw type sand transporter. Hence, it is an important guiding significance to the structural optimization design of screw conveyer.

Numerical Simulation of Flow Field around DLR_F4 Using Meshless Method

In order to investigate the calculation ability of meshless method and calculation precision for lift and drag force coefficient based on N-S equations with S-A turbulence model and Euler equations, numerical simulation of flow field around the DLR-F4 wing-body, supplied by the AIAA Drag Prediction Workshop, is employed using meshless method. Furthermore, the calculated results are compared with experiment results and Waller’s simulation results achieved by MGAERO software. It’s found that the present simulation results without consideration of fluid viscosity don’t agree well with Waller’s and experimental results. The present simulation results with consideration of fluid viscosity were found to be in good agreement with experimental results. These results indicate that meshless method coupled with S-A turbulence model could predict the natural flow characteristic around the DLR-F4 wing-body configuration well.

Kinetic analysis of surface roughness in a microchannel

A flow field numerical simulation was performed for a 2D compressible gas flow through a rough microchannel using the kinetic S-model equation with the Maxwell diffuse reflecting boundary condition at the solid wall. The implicit scheme for the solution of the S-model equation was applied and the algorithm using massive parallelization in both physical and velocities spaces has been optimized. The roughness geometry is modeled as a series of triangular obstructions with the relative roughness ∊ equals to 1.25%, 2.5% and 5%. Wide ranges of Mach and Knudsen numbers were considered. Obtained results are compared with existing expressions and available numerical results. It was found that the surface roughness has an important influence on friction factor. In particular, this effect becomes a more significant with the decrease of the Knudsen number. Compressible gas flow is also sensitive to the height of the wall roughness element. Nevertheless, for a high rarefied gas both compressibility and roughness effects become weak.

Numerical Simulation of Flow Field in the New Reactor with Two-Phase Fluid

On the basic of the PIV flows field measurement, mature commercial software to fit and test heat plate reactor momentum transfer mathematical model are used and the flow field in various operation conditions of heat plate reactor is simulated. The transfer process of two-phases flow is complicated, the ideal even bubbles model is used to simulate, analyze and calculate, the deviation values of temperature profile of two-phases flow and flow profile of H 2O-Air are minor, but they are high than that of homogeneous phase flow. We use the mature business software (CFX) of CFD not only to fit, prove the momentum and heat transfer model in reactor with the experiment data of flow profile and temperature profile, but also to simulate the whole flow profile and temperature profile of two-phase fluids, their deviation values between the calculated values and experiment value are lower than the values simulated by traditional empirical formula, these will provide analysis of the transfer process in reactor with reliable mechanism model and computing method.

Three-dimensional flow field numerical simulation and performance analysis for a new type canned motor pump

A new type of canned motor pump with extensive application value is designed, researched, and developed in this article. In order to grasp the characteristic of the internal flow field of the pump, the internal flow field is simulated numerically by using FLUENT software with the standard k–ɛ turbulence model, SIMPLEC algorithm, and multiple reference frame model. The distribution of the pressure and velocity of the flow in the canned motor pump is analyzed in different working conditions. Moreover, the head and efficiency of the pump is predicted based on the simulation results, which show that the head and efficiency of the canned motor pump in small flow rate will be better. The performance of the canned motor pump can be improved by appropriately increasing the outer diameter of the impeller and the base diameter of the volute. The results of the numerical simulation are in accord with theoretical analysis, which verifies the correctness of the numerical simulation. The investigations have important theoretical guiding significance for the design of the canned motor pump.

LES-Based Numerical Simulation of Flow Noise for UUV with Full Appendages

Numerical simulation of flow field and flow noise was carried out on SUBOFF with Lighthill acoustical analogy and large eddy simulation method. The results agreed well with the numerical and experimental results obtained from published literature. The validation of the computational method of flow noise used in this paper was carried out. The geometric model was established for the unmanned underwater vehicle with full appendages and the flow field’s computational region discretization was carried out by using structural grid. Numerical simulation of flow noise for unmanned underwater vehicle with full appendages was taken. The numerical results show that the angle of attack has little effect on the flow noise level of the vehicle while the angle ranged from 0° to 4°. Compared with the “＋”-type rudders, the flow noise level of the underwater vehicle with “X”-type rudders is about 3dB lower.

J061052 櫛刃構造フローバッテリーにおける反応流動シミュレーション(〔J061-05〕燃料電池・二次電池におけるナノ・マイクロ現象とマクロ性能(5):各種電池)

J061052 櫛刃構造フローバッテリーにおける反応流動シミュレーション(〔J061-05〕燃料電池・二次電池におけるナノ・マイクロ現象とマクロ性能(5):各種電池)

Optimization study of artificial reef assemblage based on the numerical simulation of flow field

Based on the aggregation experiments of feature-reef trough,the occurrence frequency of Sparus Macrocephalus larvae around artificial fish reefs was studied with different structures and at different background velocities.The highest frequency of fish occurrence,space volume of flow velocity of 0.7 times and0.8 times to background were considered as indexes of wake vortex range.The space volume with vertical upwelling velocity 0.1 time and 0.2 time of the upwind horizontal velocity was considered as the index of upwelling range.Based on Fluent with a turbulence model named LES(Large Eddy Simulation),a numerical trough was built and four unit-reef assemblages as an example were adopted to analyze the difference and merits of various assemblages' flow effect.The result showed it was appropriate to place 20-30 unit reefs(cube,3 meters of side length)as a 5-point symmetric mode,and 1-2 times reef distance in reef area,as this could not only bring about synergistic effect of reefs,but also optimize the regulation range of unit-reef.

A Study of Thermal Response and Flow Field Coupling Simulation around Hayabusa Capsule Loaded with Light-Weight Ablator

The numerical simulation of flow field around Hayabusa capsule loaded with light-weight ablator thermal response coupled with pyrolysis gas flow inside the ablator was carried out. In addition, the radiation from high temperature gas around the capsule was coupled with flow field. Hayabusa capsule reentered the atmosphere about 12 km/sec in velocity and Mach number about 30. During such an atmospheric entry, space vehicle is exposed to very savior aerodynamic heating due to convection and radiation. In this study, Hayabusa capsule was treated as a typical model of the atmospheric entry spacecraft. The light-weight ablator had porous structure, and permeability was an important parameter to analyze flow inside ablator. In this study, permeability was a variable parameter dependent on density of ablator. It is found that the effect of permeability of light-weight ablator was important with this analysis.

RETRACTED: Computational investigation of powder coating of nanoparticles in supersonic and hypersonic impactors

Abstract In this study, numerical simulation of flow field in a supersonic/hypersonic impactor with one or two nozzles was carried out using a commercial computational fluid dynamics (CFD) software FLUENT. The objective was to investigate the effects of working parameters such as pressure ratio (50

Simulation of Scavenging Process in a Two-Stroke Gasoline Engine

Three-dimension transient numerical simulation of flow field in the transfer ports , exhaust port, intake port, crankcase and cylinder system of two-stroke gasoline engine was studied by using CFD software Fire, and the situations of airflow movement and exhaust gas distribution were presented dynamically in the scavenging process. The results show that flow field structure of the upper cylinder is mainly comprised of a pair of toroidal vortex and tumble vortex, while flow field structure of the lower cylinder is mainly comprised of four radial swirls and "short-circuiting" fuel losses. Along with the progress of scavenging process, the area of fresh charge and mixture increase while the exhaust gas area decreases accordingly. When the piston reaches to the BDC (bottom dead center), the exhaust gas area almost disappears.