Numerical simulation of the flow field in a bioreactor

2000 ◽  
Vol 41 (4-5) ◽  
pp. 207-210 ◽  
Author(s):  
S. Ester ◽  
X. Guo ◽  
A. Delgado
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Numerical Method ◽  
Mechanical Behaviour ◽  
Numerical Code ◽  
Measurement Instruments ◽  
Local Flow ◽  
Velocity Pressure ◽  
Detailed Picture ◽  
Good Agreement

In order to give detailed information about the local flow field in a bioreactor a numerical method has been developed. This method gives information about the velocity, pressure and temperature in each point of the reactor, avoiding the problems caused by placing measurement instruments inside. Comparisons of experiments and numerical results show good agreement. The functionality and physical fundamentals of this tool are described. This is followed by explaining a reasonable application of the numerical code in the field of biological reactors. The reactors considered are filled with polydisperse, spherical support particles. From the results of the simulation a detailed picture of a reactor's fluid mechanical behaviour is drawn. This includes the quantification of mechanical stresses on the biofilm surface as well as information about the inflow, outflow and channelling behaviour of a reactor. Furthermore the effect of polydisperse support carries in discussed.

scholarly journals Experimental and CFD Studies of the Hydrodynamics in Wet Agglomeration Process

2018 ◽  
Vol 2 (3) ◽  
pp. 32 ◽  
Author(s):  
Benjamin Oyegbile ◽  
Guven Akdogan ◽  
Mohsen Karimi
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Analysis ◽  
Outer Region ◽  
Tangential Velocity ◽  
Numerical Code ◽  
Cfd Model ◽  
Rotating Disc ◽  
Batch Mode ◽  
Agglomeration Process

In this study, an experimentally validated computational model was developed to investigate the hydrodynamics in a rotor-stator vortex agglomeration reactor RVR having a rotating disc at the centre with two shrouded outer plates. A numerical simulation was performed using a simplified form of the reactor geometry to compute the 3-D flow field in batch mode operations. Thereafter, the model was validated using data from a 2-D Particle Image Velocimetry (PIV) flow analysis performed during the design of the reactor. Using different operating speeds, namely 70, 90, 110, and 130 rpm, the flow fields were computed numerically, followed by a comprehensive data analysis. The simulation results showed separated boundary layers on the rotating disc and the stator. The flow field within the reactor was characterized by a rotational plane circular forced vortex flow, in which the streamlines are concentric circles with a rotational vortex. Overall, the results of the numerical simulation demonstrated a fairly good agreement between the Computational Fluid Dynamics (CFD) model and the experimental data, as well as the available theoretical predictions. The swirl ratio β was found to be approximately 0.4044, 0.4038, 0.4044, and 0.4043 for the operating speeds of N = 70, 90, 110, and 130 rpm, respectively. In terms of the spatial distribution, the turbulence intensity and kinetic energy were concentrated on the outer region of the reactor, while the circumferential velocity showed a decreasing intensity towards the shroud. However, a comparison of the CFD and experimental predictions of the tangential velocity and the vorticity amplitude profiles showed that these parameters were under-predicted by the experimental analysis, which could be attributed to some of the experimental limitations rather than the robustness of the CFD model or numerical code.

Numerical Simulation of Flow in a Horizontal Sedimentation Tank

2011 ◽  
Vol 130-134 ◽  
pp. 3624-3627
Author(s):  
W.L. Wei ◽  
Zhang Pei ◽  
Y.L. Liu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Secondary Flow ◽  
Mixture Model ◽  
Turbulence Model ◽  
Two Phase ◽  
Sedimentation Tank ◽  
Phase Mixture ◽  
Good Agreement

In this paper, we use two-phase mixture model and the Realizable k-ε turbulence model to numerically simulate the advection secondary flow in a sedimentation tank. The PISO algorithm is used to decouple velocity and pressure. The comparisons between the measured and computed data are in good agreement, which indicates that the model can fully simulate the flow field in a sedimentation tank.

Numerical Simulation of Impacts of Different Types of Air Duct Outlets on Ventilation Efficiency

2013 ◽  
Vol 438-439 ◽  
pp. 1098-1103
Author(s):  
Chun Zi Nan ◽  
Ji Ming Ma ◽  
Luo Zhao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Numerical Method ◽  
Concentration Effect ◽  
Mixing Zone ◽  
Mixing Effect ◽  
Ventilation Efficiency ◽  
Different Types

To enhance the exhaust efficiency during ventilation, three types of air duct outlets were imported. According to the characteristics of velocity distribution simulated by numerical method, the flow field is divided into the mixing zone and the exhaust zone. The gradual contracted air duct outlet can enhance the mixing effect between fresh air and smoke. In the exhaust zone, however, the flow velocity on the upper section of the tunnel is weakened, which is unfavorable for smoke exhaust. Gradual expanded air duct outlet, on the contrary, may weaken the concentration effect of the airflow. The flow velocity on the upper section of the tunnel is increased in the exhaust zone, thus the flow field is more homogenized, which is in favor of smoke exhaust.

scholarly journals Numerical Simulation of Rotor in Hover and Forward Flight

2018 ◽  
Vol 179 ◽  
pp. 03011
Author(s):  
Qinghe Zhao
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Moving Grid ◽  
Steady State Flow ◽  
Forward Flight ◽  
Numerical Simulation Result ◽  
Structured Grid ◽  
Pressure Distributions ◽  
Good Agreement

The flow around rotor is numerical simulated in hover and forward flight based on multi-structured grid. In hover the flow field can be transformed into a steady-state flow field in the rotating coordinate system. The experimental data of Caradonna and Tung rotor is used to verify the numerical simulation result. The numerical results compare well with the experimental data for both non-lifting and lifting cases. Non-lifting forward flight is simulated and the prediction capabilities have been validated through the ONERA two-blade rotor. The pressure distributions of different positions under different azimuth angles are compared, which is in good agreement with the experimental data. There is unsteady shock wave when forward flight. Dual-time method is used to obtain unsteady flow field with rigid moving grid in the inertial system.

Numerical Simulation of Ship Turning in Level Ice

2010 ◽  
Author(s):  
Biao Su ◽  
Kaj Riska ◽  
Torgeir Moan
Keyword(s):  
Numerical Simulation ◽  
Numerical Method ◽  
Field Measurements ◽  
Full Scale ◽  
Ship Maneuverability ◽  
Ice Conditions ◽  
Level Ice ◽  
Ship Performance ◽  
Scale Data ◽  
Good Agreement

The ice-worthy ship must have a verifiable turning ability in the specified ice conditions. At present, most studies on ship maneuverability in ice are conducted by field measurements. In this paper a numerical method which is introduced for predicting ship performance in level ice, is applied to simulate ship turning in level ice. A real icebreaker is modeled in the simulation program. The calculated results are analyzed and compared with the full-scale data measured during turning tests. A good agreement is achieved.

3D ICE ACCRETION SIMULATION FOR COMPLEX CONFIGURATION BASING ON IMPROVED MESSINGER MODEL

2012 ◽  
Vol 19 ◽  
pp. 341-350 ◽  
Author(s):  
CHENGXIANG ZHU ◽  
BIN FU ◽  
ZHIGUO SUN ◽  
CHUNLING ZHU
Keyword(s):  
Flow Field ◽  
Numerical Method ◽  
Turbulence Model ◽  
Calculated Result ◽  
Complex Configuration ◽  
Ice Accretion ◽  
Improved Method ◽  
Experiment Data ◽  
Distribution Scheme ◽  
Good Agreement

Ice accretion on 3D complex configuration is studied by numerical method. The flow field is obtained by using Fluent 6.0 with S-A turbulence model, droplet trajectories and impingement characteristics are obtained using the Eulerian approach, ice shape is calculated basing on the improved Messinger model with a new runback distribution scheme. Using the method presented in this paper, ice accretion on NACA0012 is computed, and the results are in good agreement with the available experiment data. It shows preliminarily that the improved method described in this paper is feasible. Meanwhile, ice accretion on a four-element airplane is studied. According to the analysis of the calculated result, it illustrates that using the method presented in the paper can correctly simulate the ice accretion on 3D complex configuration.

Numerical Study of the Gas Flow in the Swirl Tube

2012 ◽  
Vol 550-553 ◽  
pp. 3194-3200
Author(s):  
Guang Cai Gao ◽  
Jian Jun Wang ◽  
You Hai Jin
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Reynolds Stress ◽  
Experimental Measurement ◽  
Gas Flow ◽  
Numerical Study ◽  
Separation Performance ◽  
Turbulent Model ◽  
Simulation Results ◽  
Good Agreement

The gas flow field in the swirl tube was studied by experimental measurement and numerical simulation. The results show that the simulation results based on the Reynolds stress turbulent model is in good agreement with the measured results probed by the five orifice Pitot-tube. Meantime, it is analyzed that there is short cut stream at the end of the exit tube, and at the dust discharge jaws, the particles are prone to be re-entrained from the hopper. All results above provide a base for further research on the optimization of the structure and the improvement of the separation performance of the swirl tube.

scholarly journals Experimental Study and Hydrodynamic Modelling of the Wet Agglomeration Process

2018 ◽  
Author(s):  
Benjamin Oyegbile ◽  
Guven Akdogan ◽  
Mohsen Karimi
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Analysis ◽  
Outer Region ◽  
Tangential Velocity ◽  
Numerical Code ◽  
Cfd Model ◽  
Rotating Disc ◽  
Batch Mode ◽  
Agglomeration Process

In this study, an experimentally validated computational model was developed to investigate the hydrodynamics in a rotor-stator vortex RVR agglomeration reactor having a rotating disc at the centre with two shrouded outer plates. A numerical simulation was performed using a simplified form of the reactor geometry to compute the 3D flow field in batch mode operations. Thereafter, the model was validated using data from a 2D Particle Image Velocimetry (PIV) flow analysis performed during the design of the reactor. Using different operating speeds—70, 90, 110 and 130 rpm, the flow fields were computed numerically followed by a comprehensive data analysis. The simulation results showed separated boundary layers on the rotating disc and the stator. The flow field within the reactor is characterized by a rotational plane circular forced vortex flow in which the streamlines are concentric circles with a rotational vortex. Overall, the results of the numerical simulation demonstrate a fairly good agreement between the CFD model and the experimental data as well as the available theoretical predictions. The swirl ratio β was found to be approximately 0.4044, 0.4038, 0.4044 and 0.4043 for operating speeds of N=70, 90, 110 and 130 rpm respectively. In terms of the spatial distribution, the turbulence intensity and kinetic energy are concentrated on the outer region of the reactor while the axial velocity showed a decreasing intensity towards the shroud. However, a comparison of the CFD and experimental predictions of the tangential velocity and the vorticity amplitude profiles shows that these parameters were under-predicted by the experimental analysis which could be attributed to some of the experimental limitations rather than the robustness of the CFD model or numerical code.

scholarly journals Investigation of Throttling Characteristics in Supersonic Polyclinic Inlet

2019 ◽  
pp. 21-33
Author(s):  
D.A. Vnuchkov ◽  
V.I. Zvegintsev ◽  
D.G. Nalivaychenko
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Air Flow ◽  
Flow Restriction ◽  
Air Inlet ◽  
Additional Heating ◽  
Flat Flow ◽  
Good Agreement

This paper presents an experimental investigation of throttling characteristics of a multi-wedge air inlet of a wind tunnel built for flat flow field at M = 2.5. The experiments were performed in a wind tunnel at M numbers of 2.55, 3.05 and 4.05. Results of numerical simulation of the flow in the air inlet, where air flow restriction was implemented by additional heating of the flow in the channel past the air inlet, are given for comparison. Experimental throttling characteristics are in good agreement with the values obtained from computations

Numerical Simulation and Analysis of the Muzzle Flow During the Revolving Barrel Gun Firing

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Wei Yu ◽  
Xiaobing Zhang
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Field ◽  
Splitting Method ◽  
Principal Component ◽  
Lateral Velocity ◽  
Muzzle Velocity ◽  
Cruise Missiles ◽  
Gun Firing ◽  
Good Agreement

The revolving barrel gun is the principal component of the close-in weapons system (CIWS) that provides important terminal defense against anti-ship cruise missiles that have penetrated fleet defenses. The muzzle flow field of the revolving barrel firing is extraordinarily complex. The 3D computational model was formulated to illustrate the details of the flow field produced by the revolving barrel gun firing. The algorithm of a second order monotone upstream-centered schemes (MUSCL) approach with the advection upstream splitting method (AUSM) solver was used to simulate the high pressure muzzle flow field. The interior ballistic process was coupled with the simulation. The predicted muzzle velocity and maximum bore pressure were in good agreement with those measured in gun firing. Moreover, the muzzle flow field was obtained during the revolving barrel firing and was subsequently analyzed. The maximum lateral velocity of the first and second projectile fired was about 1.6 and 3.8 m/s.

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