scholarly journals Simulation of the Filling Capability in Vane Pumps

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 283 ◽  
Author(s):  
Massimo Rundo ◽  
Giorgio Altare ◽  
Paolo Casoli
Keyword(s):  
High Speed ◽  
Maximum Flow ◽  
Vane Pump ◽  
Cfd Simulations ◽  
Flow Area ◽  
Positive Displacement ◽  
Incomplete Filling ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Flow ◽  
Dissolved Air

In positive displacement pumps, the main volumetric loss at high speed is due to the incomplete filling of the variable volume chambers. The prediction of the limit speed and of the maximum flow rate delivered by a pump can be obtained only through Computational Fluid Dynamics (CFD) simulations, since the shape, the orientation, and the movement of the chambers with respect to the inlet volume must be considered, along with the non-uniform distribution of the gaseous phase, due to the dissolved air release. In this paper, the influence of different geometric parameters on the filling of a vane pump has been investigated through the commercial software PumpLinx®. At first, a model of a reference pump has been created and validated with different configurations of the suction flow area, then a simplified model has been used for assessing the influence of the geometry of the rotating assembly. It was found that a pump with a low ratio between the axial thickness and the diameter has a higher volumetric efficiency if the chambers are fed from one side only. Opposite behaviors were found in the case of pumps with small diameters and high thicknesses. Moreover, the filling could be improved by increasing the number of chambers, and by reducing the diameter of the rotor, even only locally.

scholarly journals Numerical and Experimental Investigations on Reducing Particle Accumulation for SCR-deNOx Facilities

2019 ◽  
Vol 9 (19) ◽  
pp. 4158
Author(s):  
Zeng ◽  
Yuan ◽  
Wang
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Experimental Investigations ◽  
Duct Flow ◽  
Cfd Simulations ◽  
Particle Accumulation ◽  
Computational Fluid Dynamics Cfd ◽  
Vertical Duct

Selective catalytic reduction (SCR) is widely used to remove nitrogen oxides (NOx) in the flue gas of coal-fired power plants. The accumulation of ash particles inside the SCR-deNOx facility will increase the risk of catalyst deactivation or even damage. This paper presents the numerical and experimental investigations on the particle dispersal approach for the SCR-deNOx facility of a 1000 MW coal-fired power plant. The accumulation of different-sized particles is evaluated based on computational fluid dynamics (CFD) simulations. To prevent particles from accumulation, an optimized triangular deflector is proposed and attempts are made to find out the optimal installing position of the deflector. For the π-type SCR-deNOx facilities, the particle accumulation predominantly occurred on one side of the catalysts’ entrance, which corresponds to the inner side of the wedge-shaped turning. It is indicated that particles larger than 8.8 × 10−2 mm are responsible for the significant accumulation. The triangular deflector is proved to be an effective way to reduce particle accumulation and is found most efficient when it is installed at the high-speed area of the vertical duct. Flow model test (FMT) is carried out to validate the dispersal effect for the particle with relatively large sizes and the optimal installing position of the triangular deflector.

Measurement of the Aerodynamic Pressures Produced by Passing Trains

Joint Rail ◽  
2002 ◽  
Author(s):  
Robert A. MacNeill ◽  
Samuel Holmes ◽  
Harvey S. Lee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Electric Locomotive ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Freight Car

This paper describes measurement of the aerodynamic pressures produced by a Bombardier High-Speed Non-Electric Locomotive (HSNEL) on an adjacent stationary double-stack freight car. Static pressures are measured on the near and far-side faces of the freight containers over a range of locomotive speeds from 60 to 130 mph. This data is also compared with the pressures predicted by computational fluid dynamics (CFD) simulations.

CFD Simulations and PIV Measurements for Optimization of Flow Pattern in a Sieve Plate Extraction Column

2011 ◽  
Vol 391-392 ◽  
pp. 1464-1468
Author(s):  
Chang Chun Duan ◽  
Chun Jiang Liu ◽  
Xi Gang Yuan
Keyword(s):  
Flow Pattern ◽  
Reverse Flow ◽  
Continuous Phase ◽  
Extraction Column ◽  
Sieve Plate ◽  
Cfd Simulations ◽  
Flow Area ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Present work deals with the optimization for flow pattern of continuous phase in a sieve plate extraction column using both computational fluid dynamics (CFD) simulations and particle image velocimetry (PIV) measurements. Firstly single-phase simulation was conducted for the traditional column and it was found that there was a very large reverse flow area between every two plates. Then step by step, by changing the downcomer structure, consisting of inclining downcomers, adding baffles, slotting downcomers and baffles and adjusting the number and size of slots, the reverse flow area was decreased and thereby the flow pattern of continuous phase was optimized. Finally, an optimal flow pattern was obtained with reverse flow area greatly reduced. In order to prove the validity of the simulation results, PIV experiments of two columns were carried out and it was found that the results of simulations and experiments are in good agreement.

Comparison of the CFD Results to PIV Measurements in Kinematics of Spilling and Plunging Breakers

2020 ◽  
Author(s):  
Bülent Düz ◽  
Jule Scharnke ◽  
Rink Hallmann ◽  
Jan Tukker ◽  
Siddhant Khurana ◽  
...  
Keyword(s):  
High Speed ◽  
Piecewise Linear ◽  
Sampling Rate ◽  
Navier Stokes ◽  
Computational Domain ◽  
Cfd Simulations ◽  
High Sampling Rate ◽  
Interface Reconstruction ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Abstract The kinematics under spilling and plunging breakers are investigated using both experimental and numerical methods. In a modular laboratory flume, the breakers were generated using dispersive focusing, and the kinematics underneath them were measured utilizing the Particle Image Velocimetry (PIV) technique. Using the state-of-art high-speed video cameras and lasers, the kinematics were measured at a high sampling rate without needing phase-locked averaging. Afterwards, Computational Fluid Dynamics (CFD) simulations were carried out for comparison purposes. These simulations were run in single-phase using a finite-volume based Navier-Stokes solver with a piecewise-linear interface reconstruction scheme. The spilling and plunging breakers from the measurements were reconstructed in the computational domain using an iterative scheme. As a result a good match with the measured waves was obtained in the simulations. Results indicate that even though measured kinematics are somewhat higher than the simulated ones especially in the spilling and overturning regions, the CFD simulations can accurately capture the relevant details of the flow and produce reasonably accurate kinematics in comparison with the PIV results.

Study on the Porpoising Phenomenon of High-Speed Trimaran Planing Craft

2018 ◽  
Author(s):  
Yuming Yuan ◽  
Chao Wang
Keyword(s):  
Fluid Dynamics ◽  
High Speed ◽  
Center Of Gravity ◽  
Rolling Motion ◽  
Upward Movement ◽  
Cfd Simulations ◽  
Flow Lines ◽  
Planing Craft ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Lift

This paper presents the application of Computational Fluid Dynamics (CFD) simulations to the heaving and rolling motion of the planing craft under different speeds and centers of gravity. Comparing the flow lines, the pressure distribution at the bottom of the boat, the heave and the trim angle before instability with those elements after instability, a critical trim angle results in the early separation of the air in the bow. Meanwhile, due to effect of aerodynamic lift, the bow is lifted, which eventually leads to instability of the hull. Forward or upward movement of the center of gravity may eliminate or postpone the porpoising, the backward center of gravity may result in the unstablity of the ship. Serious porpoising is random and irregular. It will damage the structure of the hull, affect the maneuverability of the ship and threaten the safety of the crew.

Numerical and Experimental Studies of Collapsing Cavitation Bubbles for Ballast Water Treatment

2018 ◽  
Author(s):  
Chang-Wei Kang ◽  
Tandiono Tandiono ◽  
Xin Lu ◽  
Cary K. Turangan ◽  
Hafiiz Osman ◽  
...  
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Hydrodynamic Cavitation ◽  
High Speed Photography ◽  
Gas Bubble ◽  
Liquid Pressure ◽  
Cfd Simulations ◽  
Bubble Cloud ◽  
Computational Fluid Dynamics Cfd ◽  
Sudden Jump

In this paper, we report both experimental and computational studies of hydrodynamic cavitation generated by accelerating liquid through a series of constrictions. The detailed process of cavitation generation is visualized using a high-speed photography. The cavitation is initiated when a gas bubble moves towards the constrictions. The gas bubble initially accelerates, expands and then splits into smaller bubbles when it moves along the constriction. As these bubbles migrate into a large liquid compartment, they collapse violently to form a bubble cloud, owing to a sudden jump in liquid pressure in the compartment. The experimental observation is further confirmed using computational fluid dynamics (CFD) simulations. We also present experimental evidence showing a significant reduction in gram-negative Escherichia coli concentration after it passes through the constrictions.

Computational Fluid Dynamics Analysis of Gerotor Lubricating Pumps at High-Speed: Geometric Features Influencing the Filling Capability

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Giorgio Altare ◽  
Massimo Rundo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Operating Conditions ◽  
Geometric Features ◽  
Inlet Pipe ◽  
Computational Fluid Dynamics Analysis ◽  
Incomplete Filling ◽  
Computational Fluid Dynamics Cfd ◽  
Circuit Configuration

The paper presents an extensive analysis of the influence on the suction capacity of the main geometric parameters of gerotor lubricating pumps. The study was carried out using a computational fluid dynamics (CFD) model developed with the commercial software PumpLinx®. The model of a reference gerotor unit was validated experimentally in terms of delivered flow rate in different operating conditions, in open and closed circuit configuration. In the former case, different geometries of the inlet pipe were tested. In the latter, the influence of the suction pressure at constant speed was analyzed. After the model validation, several geometric features were changed to assess their influence on the volumetric efficiency in conditions of incomplete filling, such as the thickness and the diameter of the gears, the position of the inlet pipe with respect to the rotors (radial, axial, and tangential), and the shape of the port plate.

Poststall Behavior of a Multistage High Speed Compressor at Off-Design Conditions

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Fanzhou Zhao ◽  
John Dodds ◽  
Mehdi Vahdati
Keyword(s):  
High Speed ◽  
Transient Flow ◽  
Axisymmetric Flow ◽  
Axial Compressor ◽  
Transient Behavior ◽  
Rotating Stall ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd

Stall followed by surge in a high speed compressor can lead to violent disruption of flow, damage to the blade structures and, eventually, engine shutdown. Knowledge of unsteady blade loading during such events is crucial in determining the aeroelastic stability of blade structures; experimental test of such events is, however, significantly limited by the potential risk and cost associated. Numerical modeling, such as unsteady computational fluid dynamics (CFD) simulations, can provide a more informative understanding of the flow field and blade forcing during poststall events; however, very limited publications, particularly concerning multistage high speed compressors, can be found. The aim of this paper is to demonstrate the possibility of using CFD for modeling full-span rotating stall and surge in a multistage high speed compressor, and, where possible, validate the results against experimental measurements. The paper presents an investigation into the onset and transient behavior of rotating stall and surge in an eight-stage high speed axial compressor at off-design conditions, based on 3D Reynolds-averaged Navier–Stokes (URANS) computations, with the ultimate future goal being aeroelastic modeling of blade forcing and response during such events. By assembling the compressor with a small and a large exit plenum volume, respectively, a full-span rotating stall and a deep surge were modeled. Transient flow solutions obtained from numerical simulations showed trends matching with experimental measurements. Some insights are gained as to the onset, propagation, and merging of stall cells during the development of compressor stall and surge. It is shown that surge is initiated as a result of an increase in the size of the rotating stall disturbance, which grows circumferentially to occupy the full circumference resulting in an axisymmetric flow reversal.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

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