The importance of hydrodynamics in UV advanced oxidation reactors

2007 ◽  
Vol 55 (12) ◽  
pp. 53-58 ◽  
Author(s):  
A. Sozzi ◽  
F. Taghipour
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Flow Distribution ◽  
Fluence Rate ◽  
Reactor Performance ◽  
Image Velocimetry ◽  
Reactor Axis ◽  
Computational Fluid Dynamics Cfd

The flow field of UV reactors was characterised experimentally using particle image velocimetry (PIV) and modelled with computational fluid dynamics (CFD). The reactor flow was integrated with the radiation fluence rate and photolysis kinetics to calculate the overall conversion of photo-reactant components in annular UV reactors with an inlet parallel and perpendicular to the reactor axis. The results indicated that the fluid flow distribution within the reactor volume affects photo-reactor performance.

Particle Image Velocimetry and Computational Fluid Dynamics Analysis of Fuel Cell Manifold

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
Jesper Lebæk ◽  
Marcin Blazniak Andreasen ◽  
Henrik Assenholm Andresen ◽  
Mads Bang ◽  
Søren Knudsen Kær
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Image Velocimetry ◽  
Fuel Cell ◽  
Particle Image ◽  
High Current Density ◽  
Plug Flow ◽  
Flow Distribution ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Analysis

The inlet effect on the manifold flow in a fuel cell stack was investigated by means of numerical methods (computational fluid dynamics) and experimental methods (particle image velocimetry). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode manifold. Three different inlet configurations were tested: plug flow, circular inlet, and a diffuser inlet. A very distinct jet was formed in the manifold, when using the circular inlet configuration, which was confirmed both experimentally and numerically. This jet was found to be an asymmetric confined jet, known as the symmetry-breaking bifurcation phenomenon, and it is believed to cause a significant maldistribution of the stack flow distribution. The investigated diffuser design proved to generate a much smoother transition from the pipe flow to the manifold flow with a subsequent better flow distribution. A method was found in the literature to probe if there is a risk of jet asymmetry; it is however recommended by the author to implement a diffuser design, as this will generate better stack flow distribution and less head loss. Generally, the numerical and experimental results were found in to be good agreement, however, a detailed investigation revealed some difference in the results.

Theoretical Deduction and Experimental Visualization of Streamlines in Mixed-Flow Impeller

2015 ◽  
Vol 719-720 ◽  
pp. 279-283
Author(s):  
Kun Xi Qian ◽  
Teng Jing
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Logarithmic Spiral ◽  
Pressure Head ◽  
Experimental Methods ◽  
Mixed Flow ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Streamlines in mixed-flow impeller were deduced by solving partial differential equations of continuity, motion and energy; they could be simplified to be logarithmic spiral and parabola in vertical and horizontal sections respectively. Then a mixed-flow impeller was designed and manufactured, its vane had a logarithmic spiral and its shroud had a parabola form. Computational fluid dynamics (CFD) demonstrated that the streamlines in the impeller were coincided with the vane and shroud; particle image velocimetry (PIV) exhibited also that the streamlines in vane channel were really logarithmic spiral at the designing point of pumping flow rate and pressure head. It concludes that both theoretical and experimental methods presented in this paper are informative and convincing, and thus are worthy to be investigated further.

Particle Image Velocimetry Experiment and Computational Fluid Dynamics Simulation of Flow Around Rigid Cylinder

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Guangyao Wang ◽  
Ye Tian ◽  
Spyros A. Kinnas
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Image Velocimetry ◽  
Vector Fields ◽  
Particle Image ◽  
Cfd Simulation ◽  
Dynamics Simulation ◽  
Reynolds Stresses ◽  
Rigid Cylinder ◽  
Image Velocimetry

This work focuses on the study of the flow around a rigid cylinder with both particle image velocimetry (PIV) experiment and computational fluid dynamics (CFD) simulation. PIV measurements of the flow field downstream of the cylinder are first presented. The boundary conditions for CFD simulations are measured in the PIV experiment. Then the PIV flow is compared with both Reynolds-averaged Navier–Stokes (RANS) two-dimensional (2D) and large eddy simulation (LES) three-dimensional (3D) simulations performed with ANSYS fluent. The velocity vector fields and time histories of velocity are analyzed. In addition, the time-averaged velocity profiles and Reynolds stresses are analyzed. It is found that, in general, LES (3D) gives a better prediction of flow characteristics than RANS (2D).

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