A Numerical Study of Turbulent Flow Characteristics of Servo-Valve Orifices

1989 ◽  
Vol 203 (2) ◽  
pp. 139-147 ◽  
Author(s):  
D C Pountney ◽  
W Weston ◽  
M R Banieghbal
Keyword(s):  
Experimental Study ◽  
Turbulent Flow ◽  
Numerical Scheme ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Flow Patterns ◽  
Servo Valve ◽  
Valve Orifice ◽  
Numerical Predictions

A numerical scheme based on the k—e turbulences model has been employed to determine turbulent flow characteristics of servo-valve orifices. Numerical predictions of flow patterns, flow coefficients and pressure variations within the valve orifice are presented and their implications for control of spool forces and cavitation effects are considered. The limitations of the model are considered and a proposal for more effective servo-valve modelling, together with a comparable experimental study, is made.

Experimental and Numerical Study of Methanol-Water Mixture Single-Phase Heat Transfer in a Micro-Channel Heat Sink

2012 ◽  
Author(s):  
Chun K. Kwok ◽  
Matthew M. Asada ◽  
Jonathan R. Mita ◽  
Weilin Qu
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Single Phase ◽  
Numerical Study ◽  
Pure Water ◽  
Molar Fraction ◽  
Water Mixture ◽  
Micro Channel ◽  
Numerical Predictions

This paper presents an experimental study of single-phase heat transfer characteristics of binary methanol-water mixtures in a micro-channel heat sink containing an array of 22 microchannels with 240μm × 630μm cross-section. Pure water, pure methanol, and five methanol-water mixtures with methanol molar fraction of 16%, 36%, 50%, 63% and 82% were tested. Key parametric trends were identified and discussed. The experimental study was complemented by a three-dimensional numerical simulation. Numerical predictions and experimental data are in good agreement with a mean absolute error (MAE) of 0.87%.

Experimental Study of Surrogate Particle Transport and Deposition in a Square Channel Using Particle Tracking Technique

2019 ◽  
Author(s):  
Daniel Orea ◽  
Thien Nguyen ◽  
Rodolfo Vaghetto ◽  
N. K. Anand ◽  
Yassin A. Hassan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Fluid Flow ◽  
Particle Tracking ◽  
Particle Transport ◽  
Particle Deposition ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Test Facility ◽  
Square Channel ◽  
Fluid Flow Characteristics

Abstract This paper presents an experimental study of hydrodynamics flow characteristics and particle transport in a test facility. Experimental measurements of fluid flow and particle deposition are studied under isothermal conditions using particle image velocimetry (PIV) and particle tracking velocimetry (PTV) techniques. These non-intrusive optical measurement techniques have been applied in experiment conditions of Reynolds number Re = 5,077 in a 3-inch square channel and 72-inches in total length. The fluid within the channel is air seeded with aerosol droplets while the measurements of particle transport is facilitated using surrogate particles dispersed in the channel flow. Results obtained from the PIV and PTV measurements included the hydrodynamics fluid flow characteristics, and characteristics of particle transports, such as particle velocity, particle diameter distributions and particle concentration profiles. Results from the preliminary test have shown 11.08% deposition of particles. To supplement this experimental work, upstream fluid flow characteristics were provided as boundary conditions for a comparable numerical study.

Hole Cleaning in Horizontal Wells Using Viscoelastic Fluids: An Experimental Study of Drilling-Fluid Properties on the Bed-Erosion Dynamics

SPE Journal ◽  
2020 ◽  
Vol 25 (05) ◽  
pp. 2178-2193
Author(s):  
Mehmet Meric Hirpa ◽  
Ergun Kuru
Keyword(s):  
Experimental Study ◽  
Fluid Flow ◽  
Turbulent Flow ◽  
Elastic Properties ◽  
Shear Viscosity ◽  
Drilling Fluid ◽  
Flow Characteristics ◽  
Horizontal Pipe ◽  
Polymer Fluid ◽  
Bed Erosion

Summary An experimental study was conducted to determine the influence of fluid elastic properties on the critical velocity, frictional pressure drops, and the turbulent-flow characteristics of polymer-fluid flow over a sand bed deposited in a horizontal pipe. Fluids were prepared using a special technique, which allowed for the alteration of fluid elastic properties while keeping the shear viscosity constant. By conducting experiments under controlled conditions, we were able to quantify the individual effect of the fluid elasticity (independent from shear viscosity) on the critical flow rate for bed erosion and the turbulent-flow characteristics of polymer-fluid flow over the stationary sand bed. Results showed that higher critical velocities were required for the onset of the bed erosion when we use the fluid with higher elasticity.

A Numerical and Experimental Study of Laminar Unsteady Lid-Driven Cavity Flows

2017 ◽  
Author(s):  
K. M. Akyuzlu
Keyword(s):  
Experimental Study ◽  
Steady State ◽  
Flow Field ◽  
Numerical Study ◽  
Working Fluid ◽  
Cavity Flows ◽  
Square Cavity ◽  
Measured Velocity ◽  
Driven Cavity ◽  
Numerical Predictions

An experimental and numerical study was conducted to study unsteady lid-driven cavity flows. More specifically, the development of the circulation patterns inside a square cavity due to the movement of a rigid impermeable lid at constant velocity was observed experimentally and predicted numerically by CFD codes. Particle Image Velocimeter (PIV) technique was used to determine the flow field as it develops from stagnation to steady state inside a one inch (25.4 mm) square cavity driven by an impermeable lid. To avoid the three dimensional effects on the primary vortex, the depth of the cavity is taken to be 5 inches (127 mm). Working fluid is water and it is seeded with hallow glass spheres with 10 microns diameter. Experimental study was conducted for different lid velocities corresponding to Reynolds numbers for laminar to intermittent turbulence. The numerical study was carried out using commercial and in-house CFD codes for the steady state case, and using a commercial CFD code for the unsteady case. The predictions of unsteady flow field inside the two-dimensional square cavity were made using these codes which employ second order accurate (temporally and spatially) implicit numerical schemes. A time and mesh independence study was carried out to determine the optimum mesh size and time increment for the unsteady case study. Comparisons of the numerically predicted and experimentally measured velocity fields are made for steady and unsteady cases. The results indicate that the numerical predictions capture the characteristics of the circulation inside the cavity reasonably well however the magnitude of the velocities are underestimated.

Influence of weak wall undulations on the structure of turbulent pipe flow: an experimental and numerical study

1985 ◽  
Vol 160 ◽  
pp. 47-75 ◽  
Author(s):  
M. P. Chauve ◽  
R. Schiestel
Keyword(s):  
Water Flow ◽  
Pipe Flow ◽  
Numerical Study ◽  
Reverse Flow ◽  
Flow Characteristics ◽  
Flow Region ◽  
Reynolds Numbers ◽  
Turbulent Energy ◽  
Turbulent Pipe Flow ◽  
Numerical Predictions

The influence of weak periodic wall undulations on the structure of turbulent pipe flow has been studied in three ways: measurements in air flow using pressure probes and hot-wire techniques, visualizations in water flow and numerical predictions based on a turbulence (k-ε) model. The flows at Reynolds numbers of 30000 and 115000 have been particularly investigated. The flow characteristics proved to be very different from those observed in a straight pipe. Calculations and experiments agree well for the mean- and turbulent-energy fields; however the detailed behaviour of some local quantities such as anisotropy of the Reynolds stress is not well predicted particularly in the crest region. So the performances and the limitations of classical closure have been appraised. The existence of an unsteady reverse-flow region downstream of every crest suggested by measurements and calculations has been clearly confirmed by visualizations in water flow.

Experimental study on flow characteristics of ice slurry through a T-junction Part II: Turbulent flow

2020 ◽  
Vol 116 ◽  
pp. 82-88
Author(s):  
Hiroyuki Kumano ◽  
Takuya Kobayashi ◽  
Takashi Morimoto ◽  
Tatsunori Asaoka
Keyword(s):  
Experimental Study ◽  
Turbulent Flow ◽  
Flow Characteristics ◽  
Ice Slurry

Numerical Study of Friction Factor and Heat Transfer Characteristics for Single-Phase Turbulent Flow in Tubes with Helical Micro-Fins

2012 ◽  
Vol 59 (4) ◽  
pp. 469-485 ◽  
Author(s):  
Piotr Jasiński
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Numerical Simulations ◽  
Friction Factor ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Thermal Characteristics ◽  
Pressure Drops ◽  
Experimental Stand ◽  
Helical Angle

The paper presents a numerical study on the heat transfer and pressure drop, related to flow in pipes with helical micro-fins. For all tested geometries, one applied a constant wall heat flux and fully developed 3D turbulent flow conditions. The influence of the angle of micro fins (referred to the tube axis) on thermal-flow characteristics were tested. The value of this angle was varied - with a step of 10 degrees - from 0 to 90 degrees (representing grooves parallel and perpendicular to the axis, respectively). Before numerical investigation, the pipe with helical angle of 30 degree was tested on an experimental stand. The results obtained from experiment and numerical simulations were compared and presented on the charts. As an effect of the numerical simulations, the friction factor f and Nusselt number characteristics was determined for the range of Re=104 ÷ 1.6 × 106. The analysis of the results showed high, irregular influence of the helical angle on thermal characteristics and pressure drops. Additionally, the ratios: f / fplain, Nu/Nuplain and efficiency indexes (Nu/Nuplain)/( f / fplain) as a function of the Reynolds number for every helical angle were shown on the charts.

Numerical Investigation of 3-D Turbulent Flow in Orifice Plate within a Pipe

2015 ◽  
Vol 761 ◽  
pp. 27-31
Author(s):  
Mohamed Abed Alabas Siba ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Mohd Zaki Nuawi ◽  
Rasidi Rasani
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Turbulent Flow ◽  
Finite Volume ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Orifice Plate ◽  
Navier Stokes ◽  
Volume Method

A numerical study of the turbulent flow in an orifice plate within a pipe is carried out by utilizing the Navier-Stokes (N-S) equations. The governing equations are solved using primitive variables with a finite volume method (FVM) and simulated using the finite volume based commercial CFD code ANSYS. The study investigates the influences of Reynolds numbers (Re = 5000, 10000, and 15000) and aspect ratio (β = 0.2, 0.3, and 0.5), on the flow characteristics, i.e. the velocity profile, the differential pressure, and the vorticity, and on the mechanical properties, i.e. the strain, the stress, and the total deformation of the flow around and beyond the orifice. It is found that as the Reynolds number increases, the flow velocity and the pressure increase. The vorticity images show a slightly different behavior. As the Reynolds number has its own effect on the results, it is also found that the aspect ratio affects the results more significantly. The flow patterns are presented for unsteady flow throughout the orifice plate at different values of the Reynolds number.

Sign in / Sign up

Export Citation Format

Share Document