Investigation of the Submerged Depth of Aeration Impellers in an Oxidation Ditch by Numerical Simulation

2012 ◽  
Vol 178-181 ◽  
pp. 429-432
Author(s):  
Y. L. Liu ◽  
B. Lv ◽  
W.L. Wei
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Average Velocity ◽  
Sewage Treatment ◽  
Processing System ◽  
Simulation Method ◽  
Velocity Fields ◽  
Oxidation Ditch ◽  
Depth Direction ◽  
Sewage Treatment System

In this paper, the flow structure of the oxidation ditch was studied using numerical simulation method and different submerged depth of aeration impellers. The computed velocity fields were analyzed, which shows that under the same conditions, and by using the optimal submerged depth the average velocity of the flow in oxidation ditch is increased and the velocity near-bottom has increased significantly. The results of comparisons show that the velocity distribution is more uniform along the depth direction, and that the flow velocity distribution structure can prevent sludge from settling in the oxidation ditch processing system at the submergence ratio called the optimal submergence ratio, which helps to improve the efficiency of oxidation ditch sewage treatment system.

Investigation of Effects of Baffle Configuration on the Performance of a Fixed-Cone Valve by Gas-Liquid Two-Phase Model

2012 ◽  
Vol 166-169 ◽  
pp. 1824-1829
Author(s):  
W.L. Wei ◽  
B. Lv ◽  
Y.L. Liu ◽  
X.F. Yang
Keyword(s):  
Numerical Simulation ◽  
Energy Dissipation ◽  
Turbulent Flow ◽  
Average Velocity ◽  
Simulation Method ◽  
Velocity Fields ◽  
Two Phase ◽  
Pressure Fields ◽  
New Type ◽  
Conventional Type

Nested type Fixed-Cone Valve, numerical simulation, energy dissipating, turbulent flow Abstract: In this paper, In this paper, a new type of Fixed-Cone Valve was proposed by improving the conventional type Fixed-Cone Valve .The flow fields of the two kinds of Fixed-Cone Valves were studied by using numerical simulation method .The computed pressure fields and the velocity fields were analyzed ,which shows that under the same conditions ,and by using the nested Fixed-Cone valve, the pressure of the upstream pipe and the cone valve and the average velocity along the downstream pipeline are reduced ,but the rate of energy dissipation is increased.

Research on the Shape of Oxidation Ditch Diversion Wall

2012 ◽  
Vol 178-181 ◽  
pp. 419-423
Author(s):  
Y. L. Liu ◽  
B. Lv ◽  
W.L. Wei
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Simulation Method ◽  
Flow Patterns ◽  
Oxidation Ditch ◽  
Bend Flow ◽  
The Common ◽  
Equal Thickness ◽  
Common Shape ◽  
Velocity Region

Diversion wall can improve bend flow patterns in an oxidation ditch. In this paper, a non-equal thickness diversion wall was proposed, and studied by numerical simulation method. The simulated velocity field of the new shape of oxidation ditch diversion wall was compared with that of the common shape diversion wall under the same boundary conditions, which shows that the new shape can better improve the bend flow patterns in an oxidation ditch, and reduce the size of the backflow area and increase the high-velocity region in the channel.

Three-dimensional numerical simulation of velocity field distribution in an oxy-coal combustor-melter-separator furnace

2021 ◽  
Vol 118 (5) ◽  
pp. 510
Author(s):  
Yao-zong Shen ◽  
Kai Zhao ◽  
Zheng Kong ◽  
Yu-zhu Zhang ◽  
Yan Shi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Velocity Distribution ◽  
Molten Pool ◽  
Dead Zone ◽  
Sudden Change ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Simulation Method ◽  
Distribution Area

In view of the influence of tuyere layout change on velocity field in oxy-coal combustor-melter-separator furnace, three-dimensional numerical simulation method was used to compare the distribution of velocity field in the furnace under different tuyere layout. The purpose is to explore the influence of the velocity distribution on the molten pool flow in the process of multi-tuyere injection. It is shown that the maximum velocity of the upper and lower tuyeres is 60 m/s and 50 m/s. And the change of tuyere has a significant effect on the velocity distribution in the molten pool, and the sudden change of velocity near the tuyere will trigger a certain scale of gyratory zone. In addition, the change of tuyere arrangement will result in the concentration of velocity distribution in the molten pool and the increase of flow dead zone, while the change of tuyere spacing will not only promote the increase of flow dead zone, but also reduce the velocity distribution area.

Numerical Simulation of the Influence of Outer Chamber Height on Flow Field in Circumfluent Cyclone Separator

2013 ◽  
Vol 694-697 ◽  
pp. 555-559
Author(s):  
Ji Hai Duan ◽  
Xing Xing Guan
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Flow Field ◽  
Optimization Design ◽  
Simulation Method ◽  
Velocity Fields ◽  
Cyclone Separator ◽  
Outer Chamber ◽  
Pressure Fields ◽  
Chamber Height

Through the numerical simulation method, the Reynolds stress turbulence model (RSM) was used to simulate the flow field of circumfluent cyclone separator with three different outer chamber heights. Three circumfluent cyclones (CFC), with different outer chamber heights, are compared with each other. Pressure fields, velocity fields and pressure drop have been investigated. The results show that in a certain range, the outer chamber height of circumfluent cyclone separator has an optimum value, which can have higher separate efficiency and lower pressure drop. This provides a strong theoretical basis for the local optimization design of the cyclone.

The Numerical Investigation of Configuration Improvement on Gas Distributor in a Hydrogenated Reactor

2013 ◽  
Vol 781-784 ◽  
pp. 2847-2850
Author(s):  
Cai Xia Li ◽  
Si Min Wang ◽  
Shi Feng Xu ◽  
Jian Wen
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Velocity Distribution ◽  
Numerical Investigation ◽  
Center Manifold ◽  
Simulation Method ◽  
Hydrogenation Reaction ◽  
Instructional Information ◽  
Gas Distributor ◽  
The Stability

Gas distributor is of vital significance to the stability of hydrogenation reaction. The distribution performance of original style was studied with CFD numerical simulation method and an improved distributor was proposed in this paper. Compared with the original style, the new structure overcame the center-manifold phenomenon. The velocity distribution of the new distributor at evaluation plane was more uniform and pressure drop was smaller. The distribution performance of the new distributor was better, and the improved structure of the new distributor was obtained through further investigation, which will provide instructional information for industry application.

Application of Programmable Logic Controller in Sewage Treatment

2014 ◽  
Vol 910 ◽  
pp. 332-335 ◽  
Author(s):  
Zi Sheng Zhang ◽  
Bo Feng Liu ◽  
Shu Qing Guo ◽  
Deng Yuan Song ◽  
Zhan You Wang
Keyword(s):  
Automatic Control ◽  
Sewage Treatment ◽  
Control Variable ◽  
Manual Control ◽  
Programmable Logic ◽  
Oxidation Ditch ◽  
Sludge Dewatering ◽  
Development Platform ◽  
Automation Control ◽  
Sewage Treatment System

In order to seek a better way of control in sewage treatment, a control system which consisted of water unit, sand unit, the oxidation ditch unit, precipitation unit and sludge dewatering unit was designed. The paper investigates various controllable parameters in sewage treatment system and the way of present common automation control. We designed manual control variable aeration program and two automatic control subroutine which included thickness grille and pumping station by using WIN 32 software. The program is designed in Siemens STEP 7 V5.5 software development platform and chose the 10 input contacts which are I0.0~I0.7, I1.0~I1.1 and 10 output contact which are Q1.0~Q1.1, Q0.0~Q0.7.This design achieves automatic control and improves the purifying efficiency on the premise of ensuring water quality.

Numerical simulation of the effects of canopy properties on airflow and pollutant dispersion in street canyons

2021 ◽  
pp. 1420326X2110051
Author(s):  
Le Wang ◽  
Wen-Xin Tian ◽  
Xiu-Yong Zhao ◽  
Chuan-Qing Huang
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Street Canyon ◽  
Pollutant Dispersion ◽  
Simulation Method ◽  
Tree Canopy ◽  
Pollutant Concentration ◽  
Air Velocity ◽  
Street Canyons ◽  
Leaf Distribution

The air flow and pollutant concentration fields in a street canyon affected by trees could affect the comfort and health of residents. At present, the description of the non-uniform/discontinuous distribution of leaves is difficult. In this study, the leaf distribution in the canopy was characterized by establishing non-continuous (uniform/random) algorithm based on a numerical simulation method, and the effects of canopy properties including, height, porosity and uniform/random leaf distribution, on the airflow and pollutant concentration fields in urban street canyons were investigated. The position of the tree canopy was found to directly affect the airflow field form and the air velocity distribution in the street canyon at low inflows. The average air velocity in the street canyon could be reduced significantly when the top of the tree canopy is near the top of the street canyon. The air velocity and pollutant concentration in the street canyon would vary only slightly due to the canopy porosity. Due to the increasing canopy porosity, the air velocity would increase, and the pollutant concentration would be reduced. The leaves are non-continuous and uniformly distributed at constant porosity, which does not significantly change the velocity distribution and pollutant concentration in the street canyon.

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