A new multi-scale model based on CFD and macroscopic calculation for corrugated structured packing column

AIChE Journal ◽  
2013 ◽  
Vol 59 (8) ◽  
pp. 3119-3130 ◽  
Author(s):  
B. Sun ◽  
L. He ◽  
B.T. Liu ◽  
F. Gu ◽  
C.J. Liu
Keyword(s):  
Scale Model ◽  
Structured Packing ◽  
Multi Scale ◽  
Model Based ◽  
Packing Column

Numerical Investigation of Flow in an Asymmetric Plane Diffuser Using a Multi-Scale Turbulence Model

2014 ◽  
Vol 654 ◽  
pp. 51-56
Author(s):  
Zhong Shi ◽  
Zhi Qiang Li ◽  
Ge Gao ◽  
He Dong ◽  
Jian Guo ◽  
...  
Keyword(s):  
Turbulence Model ◽  
Average Method ◽  
Pressure Coefficient ◽  
Variable Interval ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Scale Model ◽  
Mean Velocity ◽  
Multi Scale ◽  
Model Based

The flow in an asymmetric plane diffuser was simulated using both the multiscale turbulence model based on the variable interval time average method and the standardk-εmodel based on the Reynolds average method. The numerical method used in this simulation is an unstructured staggered mesh scheme. The capability of the multi-scale model to simulate flow in an asymmetric plane diffuser has been validated. Pressure coefficient, frictional resistance coefficient and mean velocity profiles downstream are in agreement with experiments. Moreover, the results predicted by the multi-scale model are better than that predicted by the standardk-εmodel. The computational results show that the multiscale turbulence model can successfully simulate this type of separated flow.

Updating of structural multi-scale monitoring model based on multi-objective optimisation

2018 ◽  
Vol 22 (5) ◽  
pp. 1073-1088
Author(s):  
Yan Cui ◽  
Wei Lu ◽  
Jun Teng
Keyword(s):  
Objective Function ◽  
Health Monitoring ◽  
Measured Data ◽  
Structural Safety ◽  
Scale Model ◽  
Multi Objective ◽  
Multi Scale ◽  
Model Based ◽  
Monitoring Model ◽  
Global And Local

Structural safety assessments are implemented based on measured data, but the limited number of sensors restricts the comprehensive acquisition of response information in large complex structures. A concurrent multi-scale model utilises global and local simulation characteristics to expand the insufficient measured data. Thus, good global and local simulation capability is necessary for structural health monitoring-oriented multi-scale model, and the updating of this monitoring model needs to consider the multi-type responses that are obtained from different structural scales. However, the existing methods usually integrate multi-type responses into a single-objective function, which cannot ensure the acquisition of the optimal parameters. Moreover, in common parameter screening method, the perturbation and threshold are set artificially, which causes a strong subjectivity, and the common polynomial response surface fits poorly for highly non-linear problem. Therefore, an updating method of the structural multi-scale monitoring model based on multi-objective optimisation is proposed. For the proposed method, a variance analysis based on the orthogonal experimental design is used to screen the unique significant influence parameters. The Kriging spatial interpolation technique is used to establish the approximate surrogate model between the response and its corresponding influence parameters. Simultaneously, the responses obtained from the global and local structural scales are used to define the sub-objectives of the multi-objective function vector in order to avoid the introduction of weight coefficients. Then, the multi-objective optimisation algorithm NSGA-II is used to obtain the optimal parameter values and realise the comprehensive updating of the initial multi-scale monitoring model. Finally, based on the health monitoring system of the large shell structure of the Zhuhai Opera House, the initial multi-scale monitoring model is updated using the proposed method. The structural dynamic characteristics and local stress obtained from the initial model, updated model and the real structure are compared to validate the effectiveness of the proposed method.

Numerical Investigation of Flow Past a Backward-Facing Step Using a Multi-Scale Turbulence Model

2014 ◽  
Vol 654 ◽  
pp. 45-50
Author(s):  
He Dong ◽  
Zhi Qiang Li ◽  
Ge Gao ◽  
Zhong Shi ◽  
Jian Guo ◽  
...  
Keyword(s):  
Turbulence Model ◽  
Average Method ◽  
Pressure Coefficient ◽  
Variable Interval ◽  
Scale Model ◽  
Backward Facing Step ◽  
Mean Velocity ◽  
Multi Scale ◽  
Model Based ◽  
Flow Past

The flow past a backward-facing step was simulated using both the multiscale turbulence model based on the variable interval time average method and the standard k-ε model based on the Reynolds average method. The numerical method used in this simulation is an unstructured staggered mesh scheme. The capability of the multi-scale model to simulate flow past a backward-facing step has been validated. Both pressure coefficient and mean velocity profiles downstream are in agreement with experiments. Moreover, the results predicted by the multi-scale model are better than that predicted by the standard k-ε model. The computational results show that the multiscale turbulence model can successfully simulate this type of separated flow.

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