Investigation and Analysis of the Flow Field Induced by a Symmetrical Suction Elbow at the Pump Inlet

2019 ◽  
Author(s):  
Sebastian Muntean ◽  
Alin Ilie Bosioc ◽  
Ionel Aurel Drăghici ◽  
Liviu Eugen Anton
Keyword(s):  
Flow Field ◽  
Cross Section ◽  
Three Dimensional ◽  
Axial Direction ◽  
Numerical Results ◽  
Vortex Center ◽  
Practical Applications ◽  
Curved Pipes ◽  
Annular Cross Section ◽  
Pump Inlet

Abstract The pump inlet casing deflects the fluid flow from the inlet pipe, mainly arranged normally to the axis, into the axial direction. The pump inlet casing can take a large variety of geometrical shapes from curved pipes to three-dimensional elbows. The hydrodynamic field induced by symmetrical suction elbow (SSE) at the pump inlet is experimentally investigated in order to quantify it effects at the pump inlet. The pump test rig and the experimental setup are detailed. A SSE model is installed at the pump inlet. Laser Doppler Velocimetry (LDV) measurements are performed on the annular cross section located at the pump inlet. As a result, the map of the velocity field is determined quantifying the non-uniformities induced by SSE. Next, the full 3D turbulent numerical investigation of the flow in the SSE is performed. The numerical results on the annular cross section are qualitatively and quantitatively validated against LDV data. A good agreement between numerical results and experimental data is obtained. The hydrodynamic flow structure with several pairs of vortices is identified examining the vorticity field. However, two pairs of vortices with largest contribution to the flow non-uniformity are examined. Three parameters are considered to quantify the evolution of each vortex center: two geometrical quantities (e.g. the radial and angular coordinates) and one hydrodynamic (the magnitude of vorticity). The largest values of the vorticity magnitude are identified in the center of both vortices located behind the shaft. The 3D distribution of the vortex core filaments is visualized. As a result, the 3D geometry of the SSE and the pump shaft are identified as the main sources of the flow non-uniformity at the pump inlet. This deep analysis of the 3D flow field induced by the SSE paves the way towards an improved geometry with practical applications to real pump and pump-turbines.

Three-dimensional surfactant-covered flows of thin liquid films on rotating cylinders

2018 ◽  
Vol 844 ◽  
pp. 61-91 ◽  
Author(s):  
Weihua Li ◽  
Satish Kumar
Keyword(s):  
Free Surface ◽  
Flow Visualization ◽  
Evolution Equations ◽  
Thin Liquid Film ◽  
Three Dimensional ◽  
Axial Direction ◽  
Liquid Films ◽  
Practical Applications ◽  
Rotation Rates ◽  
Visualization Experiments

The coating of discrete objects is an important but poorly understood step in the manufacturing of a broad variety of products. An important model problem is the flow of a thin liquid film on a rotating cylinder, where instabilities can arise and compromise coating uniformity. In this work, we use lubrication theory and flow visualization experiments to study the influence of surfactant on these flows. Two coupled evolution equations describing the variation of film thickness and concentration of insoluble surfactant as a function of time, the angular coordinate and the axial coordinate are solved numerically. The results show that surface-tension forces arising from both axial and angular variations in the angular curvature drive flows in the axial direction that tend to smooth out free-surface perturbations and lead to a stable speed window in which axial perturbations do not grow. The presence of surfactant leads to Marangoni stresses that can cause the stable speed window to disappear by driving flow that opposes the stabilizing flow. In addition, Marangoni stresses tend to reduce the spacing between droplets that form at low rotation rates, and reduce the growth rate of rings that form at high rotation rates. Flow visualization experiments yield observations that are qualitatively consistent with predictions from linear stability analysis and the simulation results. The visualizations also indicate that surfactants tend to suppress dripping, slow the development of free-surface perturbations, and reduce the shifting and merging of rings and droplets, allowing more time for solidifying coatings in practical applications.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Laser Velocimeter Measurements in the Pump of an Automotive Torque Converter: Part II—Unsteady Measurements

1996 ◽  
Vol 118 (3) ◽  
pp. 570-577 ◽  
Author(s):  
K. Brun ◽  
R. D. Flack ◽  
J. K. Gruver
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
Incidence Angle ◽  
Angular Position ◽  
Three Dimensional ◽  
Torque Converter ◽  
Operating Conditions ◽  
Plane Flow ◽  
Periodic Fluctuations ◽  
Pump Inlet

The unsteady velocity field found in the pump of an automotive torque converter was measured using laser velocimetry. Velocities in the inlet, mid-, and exit planes of the pump were investigated at two significantly different operating conditions: turbine/pump rotational speed ratios of 0.065 and 0.800. A data organization method was developed to visualize the three-dimensional, periodic unsteady velocity field in the rotating frame. For this method, the acquired data are assumed to be periodic at synchronous and blade interaction frequencies. Two shaft encoders were employed to obtain the instantaneous angular position of the torque converter pump and turbine at the instant of laser velocimeter data acquisition. By proper “registration” of the data, visualizing the transient interaction effects between the stator and the pump, and between the pump and the turbine, was possible. Results showed strong cyclic velocity fluctuations in the pump inlet plane as a function of the relative stator-pump position. Typical percent periodic fluctuations in the through flow velocity were 70 percent of the average throughflow velocity. The upstream propagation influence of the turbine on the pump exit plane flow field was seen to be smaller. Percent periodic fluctuations of the throughflow velocity were typically 30 percent. The effect of the stator and turbine on the midplane flow field was seen to be negligible. The incidence angle at the pump inlet fluctuated by 27 and 14 deg for the 0.065 and 0.800 speed ratios, respectively. Typical slip factors at the exit were 0.965 and fluctuated by less than 1 percent.

Influences of Axial Gap Between Blade Rows on Secondary Flows and Aerodynamic Performance in a Turbine Stage

2009 ◽  
Author(s):  
K. Yamada ◽  
K. Funazaki ◽  
M. Kikuchi ◽  
H. Sato
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Axial Direction ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Stator Vane ◽  
Is Design ◽  
Probe Measurements

A study on the effects of the axial gap between stator and rotor upon the stage performance and flow field of a single axial flow turbine stage is presented in this paper. Three axial gaps were tested, which were achieved by moving the stator vane in the axial direction while keeping the disk cavity constant. The effect of the axial gap was investigated at two different conditions, that is design and off-design conditions. The unsteady three-dimensional flow field was analyzed by time-accurate RANS (Reynolds-Averaged Navier-Stokes) simulations. The simulation results were compared with the experiments, in which total pressure and the time-averaged flow field upstream and downstream of the rotor were obtained by five-hole probe measurements. The effect of the axial gap was confirmed in the endwall regions, and obtained relatively at off-design condition. The turbine stage efficiency was improved almost linearly by reducing the axial gap at the off-design condition.

Investigation of Fan Rotor Interaction With Pressure Disturbance Produced by Downstream Pylon

2013 ◽  
Author(s):  
Tomonori Enoki ◽  
Hidekazu Kodama ◽  
Shinya Kusuda
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Rotor Blades ◽  
Flow Structures ◽  
Coupled Analysis ◽  
Unsteady Forces ◽  
Rotor Stator Interaction ◽  
The Impact ◽  
Potential Pressure

This paper presents an investigation of fan rotor interaction with potential pressure disturbances produced by a downstream pylon. Three-dimensional unsteady viscous analyses are performed for two fan rotor-stator-pylon configurations with different axial gaps between the stator and the pylon, and compared with the experimental results. To clarify the impact of the rotor-pylon interaction on the potential pressure flow field, a numerical analysis for the configuration in which a fan rotor is removed is also performed and compared with the numerical results with fan rotor. Actuator disk analyses are also performed to interpret the flow structures observed in the experiments and the numerical results. It is found that a fan rotor-stator interaction also exists in the fan flow field, and this may impact on the upstream propagating potential flow that dominates the unsteady forces acting on the rotor blades. A coupled analysis between fan rotor and stator is essential to accurately predict the unsteady blade force.

Preliminary Numerical Investigation of Effect of Interceptor on Ship Resistance

2011 ◽  
Vol 97-98 ◽  
pp. 1085-1090 ◽  
Author(s):  
Rui Deng ◽  
De Bo Huang ◽  
Guang Li Zhou ◽  
Hua Wei Sun
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Numerical Investigation ◽  
Satisfactory Agreement ◽  
High Speed ◽  
Three Dimensional ◽  
Numerical Results ◽  
Two Dimensional ◽  
Ship Resistance ◽  
The Right

In the present work, the CFD software FLUENT is used to calculate the ship resistance and simulate the flow field around it. Comparison of the numerical results with experimental data of the ship without interceptor shows basically satisfactory agreement in the case of high-speed. In order to get the right parameters of the interceptor for the ship, some two dimensional calculation is taken to study the influence of interceptor with different size. The simulation of the three dimensional vessel with interceptor is also included, and the effect is discussed.

Process Simulation of Anchor Stirring in Crystallizer

2013 ◽  
Vol 834-836 ◽  
pp. 1548-1552
Author(s):  
Qing Wu ◽  
Li Ping Guo ◽  
Jian Xin Chen ◽  
Yin Hui Li ◽  
Ai Dang Lu
Keyword(s):  
Flow Field ◽  
Process Simulation ◽  
Chloride Solution ◽  
Single Phase ◽  
Three Dimensional ◽  
Axial Direction ◽  
Single Phase Flow ◽  
Surrounding Area ◽  
Simulation Research ◽  
Stable Flow

The paper studies the mixing effects of anchor stirring on crystallization hybrid process. The single phase flow field of three dimensional in crystallizer of 5 L is simulated by the software of Star CCM+. The change of flow field is analyzed under different stirring speed in ammonium chloride solution. The simulation research shows that the speed of fluid in the area around impeller is high, but in the surrounding and bottom area of stirring shaft is low after forming a relatively stable flow field in the crystallizer. As the stirring speed enhancement, the speed of fluid in the surrounding area of impeller and velocity gradient increase too. However, the flow of fluid in the area of axial direction is not sufficient.

Fine-Scale Simulation of Sandstone Acidizing

2005 ◽  
Vol 127 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Chunlou Li ◽  
Tao Xie ◽  
Maysam Pournik ◽  
Ding Zhu ◽  
A. D. Hill
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Direction ◽  
Three Dimensions ◽  
Scale Model ◽  
Small Scale ◽  
Fine Scale ◽  
Homogeneous Case ◽  
The Matrix ◽  
Highly Correlated

We have developed a fine-scale model of the sandstone core acid flooding process by solving acid and mineral balance equations for a fully three-dimensional flow field that changed as acidizing proceeded. The initial porosity and mineralogy field could be generated in a correlated manner in three dimensions; thus, a laminated sandstone could be simulated. The model has been used to simulate sandstone acidizing coreflood conditions, with a 1in.diam by 2in. long core represented by 8000 grid blocks, each having different initial properties. Results from this model show that the presence of small-scale heterogeneities in a sandstone has a dramatic impact on the acidizing process. Flow field heterogeneities cause acid to penetrate much farther into the formation than would occur if the rock were homogeneous, as is assumed by standard models. When the porosity was randomly distributed (sampled from a normal distribution), the acid penetrated up to twice as fast as in the homogeneous case. When the porosity field is highly correlated in the axial direction, which represents a laminated structure, acid penetrates very rapidly into the matrix along the high-permeability streaks, reaching the end of the simulated core as much as 17 times faster than for a homogeneous case.

Multi-Dimensional Numerical Free Surface VOF Modeling With Moonpool Experiments

2008 ◽  
Author(s):  
Salman Sadiq ◽  
Xiong-Liang Yao
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Best Practice ◽  
Three Dimensional ◽  
Great Influence ◽  
Numerical Results ◽  
Experimental Comparison ◽  
Pressure Distributions ◽  
Entire Flow ◽  
Set Up

The homogeneous multiphase incompressible flow past a moonpool was investigated to determine the shape of vortex, flow field and pressure distributions. In this approach, a homogeneous flow model together with the VOF method for interface capturing is used to compute the entire flow field within the moonpool. The turbulence is represented via fully homogeneous buoyant model with air and water as continuous fluids. Numerical results are verified by conducting towing tank experiments. Simulation ship moonpool applications are verification of capabilities in ANSYS CFX multi-physics code by two and three dimensional circular and square shaped moonpool subjected to flow in a channel. The numerical results indicate that cavity location with a unit factor of 1.667(L/L1), where ‘L’ is length of cavity and ‘L1’ is the distance from inflow edge; was proved to be appropriate for such cavities to have optimum performance related to moonpool hydrodynamics. Distance ‘L2’ had a negligible effect on cavity. Free surface height ‘H’ inside the cavity was maintained at 0.4 m both in numerical calculations then in experiments. Numerical and experimental comparison of results reveals that due to multiphase modeling; results diverge from actual value near phase coupling. Shape factor like internal curvature, has a great influence on vortex shape and hydrodynamic forces inside the moonpool. By analyzing these numerical results a better understanding is established for VOF models and moonpool piston phenomenon. Square shaped moonpool results and numerical results agree very well till half of the moonpool depth from free surface height. These results can be very well used for the basis of designing complex shaped moonpool having free surface. The agreement with the experimental data is within the accuracy of other simulations. Further studies and the development of Best Practice Procedures are required as a next step to reduce/avoid numerical and set-up errors and establish CFD as an industrial tool.

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