A Preliminary Analysis of a Turgo Type Turbine CFD Simulation Designed With an Integrated Dimensional Methodology

2012 ◽  
Author(s):  
Jorge Luis Clarembaux Correa ◽  
Jesús De Andrade ◽  
Miguel Asuaje
Keyword(s):  
Preliminary Analysis ◽  
Relative Velocity ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Hydrodynamic Performance ◽  
Volumetric Fraction ◽  
Hydrodynamic Parameters ◽  
Simulation Results ◽  
2D And 3D

A useful methodology in the design of a Turgo Type Turbine (TTT) has been accomplished through the theoretical calculation of the runner performance and efficiency, using 1D, 2D and 3D theory with certain simpliflying assumptions. The adaptation of several geometric and hydrodynamic parameters into the solution of the Rankine ovoids streamlines function, a three-dimensional potential flow, resulted in the design of a three dimensional TTT runner. A significant CFD simulation of this turbine was achieved, showing its hydrodynamic performance and the behaviour of the streamlines path through the buckets hit by the jet. The distribution of the water volumetric fraction was reported from the nozzle to the buckets In the same way, this numerical approach described the evolution of the velocity vectors from the water crossing the buckets. Furthermore, a comparison between the relative velocity angles from the three dimensional potential theory and the CFD simulation results was done, in order to find potential similarities from the water that actually passes into the buckets.

scholarly journals Study of the nozzle check valve with respect to its operating characteristics

2018 ◽  
Vol 180 ◽  
pp. 02044 ◽  
Author(s):  
Roman Klas ◽  
Vladimír Habán ◽  
Pavel Rudolf
Keyword(s):  
Cfd Simulation ◽  
Check Valve ◽  
Operating Characteristics ◽  
Valve Design ◽  
Pressure Fields ◽  
Valve Disc ◽  
Unsteady Operation ◽  
Simulation Results ◽  
2D And 3D ◽  
Main Operating

Several modifications were developed when designing the nozzle valve. This study offers an assessment of the properties of new modifications of the nozzle valve design. The main operating characteristics, such as loss and flow coefficients, were determined using a CFD methods. Besides mentioned coefficients, the forces acting on the valve disc are also decisive for the behavior of the valve, both in its steady and unsteady operation. It is important to examine the possible simplification and matching of CFD simulation results from 2D and 3D geometries in terms of subsequent dynamic analysis of the valve. This will be taken into consideration by comparing the above-mentioned operating characteristics, by analyzing the forces acting on the valve disc and comparing the velocity and pressure fields.

Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump

2011 ◽  
Author(s):  
Kai Wang ◽  
Houlin Liu ◽  
Shouqi Yuan ◽  
Minggao Tan ◽  
Yong Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Cfd Simulation ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Absolute Velocity ◽  
Operation Condition ◽  
Test Technique ◽  
Simulation Results

A double blades pump is widely used in sewage treatment industry, while at present the research on the internal flow characteristics of the double blades pump is very few. So, the CFD technology and the stereo PIV test technique are applied to study the inner flow in a double blades pump whose specific speed is 110.9. The commercial code FLUENT is used to simulate the inner flow in the double blades pump at 0.6Qd, 0.8Qd, 1.0Qd, 1.2Qd and 1.4Qd. The RNG k-ε turbulence model and SIMPLEC algorithm are used in FLUENT. According to the results of the three-dimensional steady numerical simulation, the distributions of velocity field in the impeller are obtained at the five different operating conditions. The analysis of the numerical simulation results shows that there is an obvious vortex in the impeller passage at off-design conditions. But the number, location and area of the vortex are different from each operation condition. In order to validate CFD simulation results, the stereo PIV is used to test the absolute velocity distribution in the double blades pump at Jiangsu University. The distributions of three-dimensional absolute velocity field at the above five different operating conditions are obtained by the PIV test, and the measured results are compared with the CFD simulation results. The comparison indicates that there are vortexes in impeller passages of the double blades pump under the five operating conditions. But as to the area of the vortex and the relative velocity values of the vortex core, there are some differences between the experiment results and the numerical simulation results. The research work can be applied to instruct the hydraulic design of double blades pumps.

Hydrodynamics and Flow Characterization of Tuna-Inspired Propulsion in Forward Swimming

2019 ◽  
Author(s):  
Junshi Wang ◽  
Huy Tran ◽  
Martha Christino ◽  
Carl White ◽  
Joseph Zhu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Underwater Vehicle ◽  
Numerical Approach ◽  
Primary Objective ◽  
Computational Effort ◽  
The Body ◽  
Hydrodynamic Performance ◽  
Immersed Boundary ◽  
Ring Structures

Abstract A combined experimental and numerical approach is employed to study the hydrodynamic performance and characterize the flow features of thunniform swimming by using a tuna-inspired underwater vehicle in forward swimming. The three-dimensional, time-dependent kinematics of the body-fin system of the underwater vehicle is obtained via a stereo-videographic technique. A high-fidelity computational model is then directly reconstructed based on the experimental data. A sharp-interface immersed-boundary-method (IBM) based incompressible flow solver is employed to compute the flow. The primary objective of the computational effort is to quantify the thrust performance of the model. The body kinematics and hydrodynamic performances are quantified and the dynamics of the vortex wake are analyzed. Results have shown significant leading-edge vortex at the caudal fin and unique vortex ring structures in the wake. The results from this work help to bring insight into understanding the thrust producing mechanism of thunniform swimming and to provide potential suggestions in improving the hydrodynamic performance of swimming underwater vehicles.

Research on the Model of Water Jet Propulsion Using Compressed Gas Based on Fluent Software

2013 ◽  
Vol 288 ◽  
pp. 276-281
Author(s):  
Xiao Gang Zhou ◽  
Jia Hua Han
Keyword(s):  
Numerical Model ◽  
Physical Model ◽  
Cfd Simulation ◽  
Water Jet ◽  
Jet Propulsion ◽  
Hydrodynamic Parameters ◽  
Compressed Gas ◽  
Fluent Software ◽  
Simulation Results

For the problems of the propeller and traditional water-jet propulsion, a new water-jet propulsion device using compressed gas is introduced in this paper. The physical model of this water-jet propulsion is designed and tested, and a numerical model of its drive device is established and the grid is divided by the software GAMBIT. The related hydrodynamic parameters are acquired through the simulation of the drive device by the software Fluent. The results of the simulations and the experiments are basically consistent. So this new water-jet propulsion method is feasible and it is an effective way to conduct the research by CFD simulation. The simulation results provide some references for designing the drive device of this water-jet propulsion model.

scholarly journals Unsteady CFD simulation of 3D AUV hull at different angles of attack

2016 ◽  
Vol 13 (2) ◽  
pp. 111-123
Author(s):  
Sudipta Ray ◽  
Dipankar Chatterjee ◽  
Sambhunath Nandy
Keyword(s):  
Cfd Simulation ◽  
Autonomous Underwater Vehicle ◽  
Turbulent Transport ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Underwater Vehicle ◽  
Three Dimensional Flow ◽  
Pressure Coefficients ◽  
Hydrodynamic Parameters ◽  
Sst Turbulence Model

An unsteady, three-dimensional flow simulation is carried out over the bare hull of the autonomous underwater vehicle currently being developed by CSIR-CMERI, Durgapur, India at various angles of attack with the help of a Finite Volume-based CFD software. The purpose of the study is to provide estimation of various hydrodynamic forces acting on the bare hull at different angles of operation. The operating range of velocity of the vehicle is 0-6 knot (0-3 m/s), considering up to 2 knots of upstream current. For the purpose of the CFD simulation, the widely-implemented RANS approach is used, wherein the turbulent transport equations are solved using the low-Re version of the SST ?-? turbulence model. The motion of the vehicle is considered within a range of the pitch angle (0<=alpha<=20). The results are presented in terms of variations of the relevant hydrodynamic parameters. The effects of the angle of attack on the drag and pressure coefficients are discussed in detail.

Numerical Study on the Effect of Stern Flap for Hydrodynamic Performance of Catamaran

2019 ◽  
Author(s):  
Peng Zhou ◽  
Liwei Liu ◽  
Lixiang Guo ◽  
Qing Wang ◽  
Xianzhou Wang
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Experimental Studies ◽  
Hydrodynamic Performance ◽  
Flow Solver ◽  
Calm Water ◽  
Unsteady Simulation ◽  
Ship Hydrodynamic ◽  
Simulation Results

Abstract This paper presents CFD simulation results of the stern flap effect with different lengths for hydrodynamic performance of catamaran moving in calm water, including resistance and sailing attitude. Inhouse viscous CFD (computational fluid dynamics) code HUST-Ship (Hydrodynamic Unsteady Simulation Technology for Ship) is used for the study. The catamaran with/without stern flap with different lengths were studied. The trim and sinkage of the catamaran were solved coupled with flow solver. Experimental studies in calm water were conducted to validate the numerical method. The comparison of hydrodynamic performance of catamaran with stern flaps of different lengths was made. The results show that the stern flap can reduce the sailing attitude and has influence for the resistance of catamaran at high-speed.

A CFD Simulation Analysis of the Water Volumetric Fraction Distribution in the Runner of a Turgo Type Turbine Designed With an Integrated Dimensional Methodology

2014 ◽  
Author(s):  
Jorge Luis Clarembaux Correa ◽  
Jesús de Andrade ◽  
Sergio Croquer ◽  
Miguel Asuaje
Keyword(s):  
Steady State ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Steady State Regime ◽  
Volumetric Fraction ◽  
Cfd Models ◽  
Fraction Distribution ◽  
State Regime

Our previous work, on development of a design methodology inspired in the analysis of One-Dimensional and Three-dimensional Theories [1], allowed to obtain a Turgo Type Turbine (TTT) bucket using 8 geometric parameters as a function of the jet diameter, and Rankine Ovoids potential flow. CFD models under steady state regime [2] made possible to verify deduced expressions for torque, output power and hydraulic efficiency. In this paper, the effects of the water volumetric fraction distribution in the runner have been included, which are significantly conclusive to understand the runner hydrodynamic behavior and highlighted several optimizations to the performance equations that could be considered as a potential novelty for these turbines. In the same way, an influence study of nozzle parameters determined that the most profitable performance is achieved for an absolute velocity angle coming from the jet of 19.8°. Finally, several differences in the flow distribution in the runner were evaluated through a non-steady state regime CFD simulation, when comparing with the steady state.

scholarly journals Computational modeling of gas mixture dispersion in a dynamic setup – 2d and 3d numerical approach

2018 ◽  
Vol 44 ◽  
pp. 00146 ◽  
Author(s):  
Andrzej Polanczyk ◽  
Zdzisław Salamonowicz
Keyword(s):  
Fluid Model ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Chlorine Concentration ◽  
Gas Mixture ◽  
Circular Profile ◽  
Volume Of Fluid Model ◽  
Two Stages ◽  
2D And 3D

The aim of the study was to prepare a mathematical model of gas mixture dispersion with the use of Computational Fluid Dynamic (CFD) technique. Three dimensional chlorine dispersion in a dynamic setup with the use of Volume of Fluid model (VOD) model was applied. The area of investigation was equal to 0.1km2 and the high of the mathematical domain was equal to 50m. Atmosphere was considered in two stages: as one direction of wind flow and no wind. Comparison of constant and dynamic conditions indicated high impact of wind. For the windless case circular profile of chlorine concentration around dispersion source was observed. While, for the wind application the main chlorine concentration moved ahead the source of dispersion.

scholarly journals 2D and 3D Potential Flow Simulation around NACA 0012 Airfoil with Ground Effect

2021 ◽  
Author(s):  
YavuzHakan Ozdemir ◽  
Baris Barlas
Keyword(s):  
Boundary Element ◽  
Potential Flow ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Ground Effect ◽  
Physical Problems ◽  
Constant Strength ◽  
Simulation Results ◽  
Naca 0012 ◽  
2D And 3D

Abstract The purpose of this paper is to develop a Boundary Element Based Method (BEM) for determining the steady potential about two and three dimensional airfoil. The numerical investigation of NACA 0012 airfoil with using Boundary Element Method is utilized. Two different physical problems of the NACA 0012 airfoil are examined: potential flow around airfoil in an unbounded fluid and potential flow prediction with ground effect. Computation of potential flow around the airfoil is investigated by the mixed constant strength source and constant strength dipole based panel method. Boundary Element Code is written in FORTRAN. To check the accuracy of the 2D boundary element based code, the validation studies are carried out by comparing the present results obtained for the NACA 0012 airfoil from the XFoil and other published simulation results. 3D results are also evaluating with the available experimental and other numerical simulation results. The numerical outcomes are examined in terms of pressure distribution and lifting force on the foil.

Transfers with a rendezvous lasting no more than one orbit between close near-circular coplanar orbits

2020 ◽  
pp. 82-93
Author(s):  
Aleksandr F. BRAGAZIN ◽  
Alexey V. USKOV
Keyword(s):  
Key Words ◽  
Relative Velocity ◽  
Free Parameter ◽  
Space Station ◽  
Characteristic Velocity ◽  
Orbital Station ◽  
Orbit Transfer ◽  
Simulation Results ◽  
The Moment ◽  
Phase Differences

Consideration has been given to orbit transfers involving spacecraft rendezvous which belong to a class of coplanar non-intersecting near-circular orbits of a spacecraft and a space station. The duration of the transfer is assumed to be limited by one orbit. The feasibility of a rendezvous using an optimal two-burn orbit-to-orbit transfer is studied. To determine a single free parameter of the transfer, i.e. the time of its start, ensuring a rendezvous at a given time or at a given velocity at the end of transfer, appropriate equations have been obtained To implement in the guidance algorithms optimal three-burn correction programs are proposed to achieve a rendezvous at a given time with a specified relative velocity at the moment of spacecraft contact. A range of phase differences at the start of maneuvering is determined, within which the characteristic velocity of the rendezvous is equal to the minimum characteristic velocity of the orbit-to-orbit transfer. The paper presents simulation results for “quick" rendezvous profiles that use the proposed programs. Key words: spacecraft, orbital station, “quick” rendezvous, orbit transfer, rendezvous program.

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