Application of hybrid RANS-LES models to the prediction of mixing time and residence time distribution: Case study of a draft tube reactor

2021 ◽  
Vol 240 ◽  
pp. 116676
Author(s):  
Gary J. Brown ◽  
David F. Fletcher ◽  
Jeremy W. Leggoe ◽  
David S. Whyte
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Draft Tube ◽  
Mixing Time ◽  
Tube Reactor

Hydrodynamic Investigation in an Annular Reactor with Mixing Time and Residence Time Distribution: Flow Rates Estimation with the Gauss-Newton Gradient Technique

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Skandar Rjeb ◽  
Ahmed Hannachi ◽  
Ratal Abdelhamid
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Search Algorithm ◽  
Mixing Time ◽  
Chemical Reactor ◽  
Computer Code ◽  
Flow Rates ◽  
Stirred Tank Reactors ◽  
Gradient Technique

In this work, flow patterns within an annular chemical reactor were characterized. The reactor was modeled by a cascade of communicating Continuous Stirred Tank Reactors (CSTRs) exchanging flow rates of variable intensities. Mixing time and Residence Time Distribution measurements were used as basis for flow modeling. A Matlab computer code has been developed to predict the exchanged flow rates through the minimization of an objective function. This paper describes the parameter estimation technique which is based on the Gauss-Newton method with a linear search algorithm. Only two opposite flow rates between reactor compartments were assumed and were identified for various mixing conditions. For the studied cases, the predicted responses were close to the experimental measurements.

scholarly journals A novel technique for residence time distribution (RTD) measurements in solids unit operations

2021 ◽  
Vol 32 (2) ◽  
pp. 611-618
Author(s):  
Atena Dehghani Kiadehi ◽  
Mikel Leturia ◽  
Franco Otaola ◽  
Aissa Ould-Dris ◽  
Khashayar Saleh
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Novel Technique ◽  
Unit Operations

scholarly journals Effects of Salt Tracer Volume and Concentration on Residence Time Distribution Curves for Characterization of Liquid Steel Behavior in Metallurgical Tundish

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 430
Author(s):  
Changyou Ding ◽  
Hong Lei ◽  
Hong Niu ◽  
Han Zhang ◽  
Bin Yang ◽  
...  
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Mass Concentration ◽  
Distribution Curve ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Residence Time Distribution Curve ◽  
Tracer Solution ◽  
Time Distribution Curve

The residence time distribution (RTD) curve is widely applied to describe the fluid flow in a tundish, different tracer mass concentrations and different tracer volumes give different residence time distribution curves for the same flow field. Thus, it is necessary to have a deep insight into the effects of the mass concentration and the volume of tracer solution on the residence time distribution curve. In order to describe the interaction between the tracer and the fluid, solute buoyancy is considered in the Navier–Stokes equation. Numerical results show that, with the increase of the mass concentration and the volume of the tracer, the shape of the residence time distribution curve changes from single flat peak to single sharp peak and then to double peaks. This change comes from the stratified flow of the tracer. Furthermore, the velocity difference number is introduced to demonstrate the importance of the density difference between the tracer and the fluid.

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