scholarly journals Evaluation of hydraulic dead-zone and particle removal efficiency in the base frame of a constructed wetland using computational fluid dynamics

2013 ◽  
Vol 27 (4) ◽  
pp. 495-502
Author(s):  
Young-Gyun Choi ◽  
Min-Cheol Park
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Dead Zone ◽  
Particle Removal

scholarly journals Investigation of dust particle removal efficiency of self-priming venturi scrubber using computational fluid dynamics

2018 ◽  
Vol 50 (5) ◽  
pp. 665-672 ◽  
Author(s):  
Sarim Ahmed ◽  
Hassan Mohsin ◽  
Kamran Qureshi ◽  
Ajmal Shah ◽  
Waseem Siddique ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Dust Particle ◽  
Removal Efficiency ◽  
Particle Removal ◽  
Venturi Scrubber

Improving the design of a pickup head for particle removal using computational fluid dynamics

2011 ◽  
Vol 225 (4) ◽  
pp. 939-948 ◽  
Author(s):  
B Wu ◽  
J Men ◽  
J Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Removal Efficiency ◽  
Inclination Angle ◽  
Gas Flow ◽  
Road Surface ◽  
Particle Model ◽  
Particle Removal ◽  
Inclination Angles

The purpose of this article is to optimize the design of a pickup head that removes particles from road surface. A validated computational fluid dynamics model was proposed to evaluate the particle removal performance of the designed pickup head with different inclination angles. The gas-particle flow through the pickup head was modelled using the EulerianLagrangian approach. The realizable k model and the discrete particle model were adopted to simulate gas flow field and solid particle trajectories, respectively. The results indicate that the inclination angle of the rear edge wall and the pressure drop across the pickup head have great impact on the particle removal performance. Both the particle overall removal efficiency and the grade efficiency increase with the increment of inclination angle, and higher pressure drop can pick up more particles from the road surface, but it would induce unnecessary energy consumption. Therefore, it is necessary to design a pickup head with high removal efficiency and low pressure drop. Through simulation, the optimal angle should be 135 for the range of the inclination angle in this study, and pressure drop is about 2400Pa. Furthermore, more information can be acquired for pickup head design.

scholarly journals Computational fluid dynamics analysis of the hydraulic (filtration) efficiency of a residential swimming pool

2018 ◽  
Vol 16 (5) ◽  
pp. 750-761 ◽  
Author(s):  
J. Zhang ◽  
N. Sinha ◽  
M. Ross ◽  
A. E. Tejada-Martínez
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Residence Time ◽  
Dead Zone ◽  
Three Dimensional ◽  
Circulation Pattern ◽  
Filtration Efficiency ◽  
Swimming Pools ◽  
Hydraulic Efficiency ◽  
Computational Fluid Dynamics Analysis

Abstract Hydraulic or filtration efficiency of residential swimming pools, quantified in terms of residence time characteristics, is critical to disinfection and thus important to public health. In this study, a three-dimensional computational fluid dynamics model together with Eulerian and Lagrangian-based techniques are used for investigating the residence time characteristics of a passive tracer and particles in the water, representative of chemicals and pathogens, respectively. The flow pattern in the pool is found to be characterized by dead zone regions where water constituents may be retained for extended periods of times, thereby potentially decreasing the pool hydraulic efficiency. Two return-jet configurations are studied in order to understand the effect of return-jet location and intensity on the hydraulic efficiency of the pool. A two-jet configuration is found to perform on par with a three-jet configuration in removing dissolved constituents but the former is more efficient than the latter in removing or flushing particles. The latter result suggests that return-jet location and associated flow circulation pattern have an important impact on hydraulic efficiency. Thus return-jet configuration should be incorporated as a key parameter in the design of swimming pools complementing current design standards.

Simulation and Analysis of Flow Field in Sludge Anaerobic Digestion Reactor based on Computational Fluid Dynamics

2017 ◽  
Vol 16 (3) ◽  
Author(s):  
Xiuqin Cao ◽  
Kun Jiang ◽  
Hao Ding ◽  
Ping Yang ◽  
Zhendong Zhao ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Anaerobic Digestion ◽  
Flow Field ◽  
Rotational Speed ◽  
Flow Behavior ◽  
Dead Zone ◽  
Fluid Velocity ◽  
Reactor Wall ◽  
Mixing Effect

AbstractBecause of the complexity of flow and the opacity of sludge, usually we can’t gain a precise and comprehensive sight of sludge flow type and its associated flow characteristics in the anaerobic digestion (AD) reactor. In the present study, we focused on the sludge rheological properties as well as the flow behavior in the digester. The viscosity decreased with the increase of shear rate, and sludge as a kind of pseudo-plastic fluid was proved. Based on computational fluid dynamics (CFD), taking sludge rheological index and rotational speed into consideration, then the flow field distribution in the digester was obtained. The fluid velocity raised with increase in rotational speed, moreover, fluid near blades had higher velocity while it was almost stagnant in the areas near reactor bottom and top as well as reactor wall and stirring shaft. The effect of rheological index on improving the velocity of fluid farther from impeller exceeded the influence on fluid at the impeller installation height. Regarding dead zone fraction as an indicator of the mixing effect, it was recommended that the suitable rotational speed for AD of 96 % moisture content sludge is 40 r/min. Finally, the reactor performance was optimized respectively from impeller form and reactor configuration, the results showed that both combined impellers and oval reactor can reduce dead zone volumes and produce a better mixing effect.

Numerical Investigation of Dusts Removal from Tramway Surface by Street Vacuum Sweeper

2011 ◽  
Vol 236-238 ◽  
pp. 1619-1622 ◽  
Author(s):  
Bo Fu Wu ◽  
Jin Lai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Pressure Drop ◽  
Removal Efficiency ◽  
Pressure Drops ◽  
Operational Safety ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

In order to enhance the operational safety of tram vehicle and reduce the wear of guide wheels mounted on the vehicle, it is necessary to remove particles such as dusts and silts from tramway surface. The aim of this paper is to evaluate the effectiveness of street vacuum sweeper for sucking up dusts from tramway surface. A numerical model was developed based on dusts removal process. Under different pressure drops across the pickup head of the street vacuum sweeper, the flow field and dusts removal efficiency were analyzed with computational fluid dynamics (CFD) method. The numerical results show that a higher pressure drop can improve the airflow field in the pickup head and results in higher dusts removal efficiency, but higher pressure drop definitely need more energy. Therefore, a balance should be taken into consideration.

scholarly journals Structural improvements on hydrodynamic separators: a computational fluid dynamics approach

2016 ◽  
Vol 74 (12) ◽  
pp. 2898-2908
Author(s):  
Joseph Albert Mendoza ◽  
Dong Hoon Lee ◽  
Sang-Il Lee ◽  
Joo-Hyon Kang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fine Particles ◽  
Swirling Flow ◽  
Particle Removal ◽  
Gravity Settling ◽  
Large Particles ◽  
Removal Efficiencies ◽  
Structural Configurations ◽  
Plate Type

Hydrodynamic separators (HDSs) have been used extensively to reduce stormwater pollutants from urbanized areas before entering the receiving water bodies. They primarily remove particulates and associated pollutants using gravity settling. Two types of HDSs with different structural configurations of the inner vortex-inducing components were presented in this study. One configuration consisted of a dip cylindrical plate with a center shaft while the other one has a hollow screen inside. With the help of computational fluid dynamics, the performance of these different types of HDSs have been evaluated and comparatively analyzed. The results showed that the particle removal efficiency was better with the cylindrical plate type HDSs than the screen type HDSs because of the larger swirling flow regime formed inside the device. Plate type HDSs were found more effective in removing fine particles (∼50 μm) than the screen type HDSs that were only efficient in removing large particles (≥250 μm). Structural improvements in a HDS such as increase in diameter and angle of the inlet pipe can enhance the removal efficiencies by up to 20% for plate type HDS while increase in the screen diameter can increase removal efficiencies of the screen type HDS.

CFD Simulation of an Airlift-Driven Raceway Bioreactor for Microalgae Cultivation

2014 ◽  
Vol 955-959 ◽  
pp. 289-292 ◽  
Author(s):  
Bin Weng ◽  
Ying Shen ◽  
Jia Cheng Chen ◽  
Hua Biao Li ◽  
Lu Ming Liu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Average Velocity ◽  
Cfd Simulation ◽  
Dead Zone ◽  
Microalgae Cultivation ◽  
Computational Fluid Dynamics Cfd

The objective of this paper is to optimize the design and structure of an airlift-driven raceway bioreactor via the computational fluid dynamics (CFD) simulation for microalgae cultivation. The calculated results showed that the airlift-driven raceway bioreactor had maximum average velocity when setting two airlift tubes (of 350 mm in length) in the middle, furthermore adding the inducing baffle structure. Under this condition, minimum dead zone ratio was obtained, which was advantageous to the microalgae cultivaiton.

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