Hydraulic efficiency of baffled disinfection contact tanks

2010 ◽  
pp. 1081-1086 ◽  
Keyword(s):  
Hydraulic Efficiency ◽  
Contact Tanks

scholarly journals Effect of Porous Baffles on the Energy Performance of Contact Tanks in Water Treatment

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1084 ◽  
Author(s):  
M. A. Kizilaslan ◽  
E. Demirel ◽  
M. M. Aral
Keyword(s):  
Energy Efficiency ◽  
Water Treatment ◽  
Porous Layer ◽  
Hydraulic Efficiency ◽  
Tracer Transport ◽  
Dispersion Effects ◽  
Conventional Design ◽  
Flow Through ◽  
Contact Tanks ◽  
Porous Zone

Three-dimensional numerical simulations are performed to evaluate the effect of porous baffles on the efficiency of water treatment contact tanks. A second-order accurate numerical model is employed for the solutions of unsteady flow and tracer transport through the porous baffles. The flow through the porous medium is characterized while using the Darcy-Forchheimer relationship. Large Eddy Simulation (LES) model is used to simulate the instantaneous mixing of the tracer in the chambers of the contact tank. Three different porosities are considered to evaluate the effect of porosity on the hydraulic and mixing efficiencies of the contact tank. Simulated time-averaged flow field shows that porous baffles that are placed at the entrance of each chamber could successfully mitigate short-circuiting and yield plug-flow conditions through the system for low porosities. Flow in the contact tank becomes laminar as the flow velocities decrease due to viscous effects and inertial resistance in the porous zone. For this case, the tracer is transported with bulk flow through the system and leaves the contact tank with a high peak seen in the Residence Time Distribution (RTD) plot. Porous layer increases the hydraulic efficiency of the conventional design from “poor” to “good” according to the baffling factor and increases the overall efficiency from “compromising” to “good” according to the AD index. Comparison of the performance of the porous layer with the previously developed slot-baffle design shows that the slot-baffle design increases the efficiency of the tank with increasing dispersion effects, whereas the porous design increases hydraulic efficiency and reduces the dispersion effects. While the porous design reduces energy efficiency by 33% due to a drastic increase in drag in the flow through porous zone, the slot-baffle design increases the energy efficiency of the conventional design by 67%.

A clear trade‐off between leaf hydraulic efficiency and safety in an aridland shrub during regrowth

2021 ◽  
Author(s):  
Guang‐Qian Yao ◽  
Zheng‐Fei Nie ◽  
Yuan‐Yuan Zeng ◽  
Muhammad Waseem ◽  
Md. Mahadi Hasan ◽  
...  
Keyword(s):  
Hydraulic Efficiency ◽  
Trade Off

scholarly journals The Relevance of Grated Inlets within Surface Drainage Systems in the Field of Urban Flood Resilience. A Review of Several Experimental and Numerical Simulation Approaches

2021 ◽  
Vol 13 (13) ◽  
pp. 7189
Author(s):  
Beniamino Russo ◽  
Manuel Gómez Valentín ◽  
Jackson Tellez-Álvarez
Keyword(s):  
Overland Flow ◽  
Drainage System ◽  
Critical Conditions ◽  
Hydraulic Efficiency ◽  
Storm Events ◽  
Urban Resilience ◽  
Urban Flood ◽  
Drainage Systems ◽  
Surface Drainage ◽  
Intense Storm

Urban drainage networks should be designed and operated preferably under open channel flow conditions without flux return, backwater, or overflows. In the case of extreme storm events, urban pluvial flooding is generated by the excess of surface runoff that could not be conveyed by pressurized sewer pipes, due to its limited capacity or, many times, due to the poor efficiency of surface drainage systems to collect uncontrolled overland flow. Generally, the hydraulic design of sewer systems is addressed more for underground networks, neglecting the surface drainage system, although inadequate inlet spacings and locations can cause dangerous flooding with relevant socio-economic impacts and the interruption of critical services and urban activities. Several experimental and numerical studies carried out at the Technical University of Catalonia (UPC) and other research institutions demonstrated that the hydraulic efficiency of inlets can be very low under critical conditions (e.g., high circulating overland flow on steep areas). In these cases, the hydraulic efficiency of conventional grated inlets and continuous transverse elements can be around 10–20%. Their hydraulic capacity, expressed in terms of discharge coefficients, shows the same criticism with values quite far from those that are usually used in several project practice phases. The grate clogging phenomenon and more intense storm events produced by climate change could further reduce the inlets’ performance. In this context, in order to improve the flood urban resilience of our cities, the relevance of the hydraulic behavior of surface drainage systems is clear.

Hydraulic Design of Inlet Guide Vane and its Full Flow Passage Numerical Simulation on Centrifugal Pump

2014 ◽  
Author(s):  
Hucan Hou ◽  
Yongxue Zhang ◽  
Zhenlin Li ◽  
Xin Zhou ◽  
Zizhe Wang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Inlet Guide Vane ◽  
Hydraulic Efficiency ◽  
Flow Passage ◽  
Setting Angle ◽  
Hydraulic Design

In order to effectively improve hydraulic performance of centrifugal pump on off-conditions, the hydraulic design of inlet guide vane (IGV) was completed by adopting two dimensional theory in-house code based on one kind of IS series of centrifugal pump, which can achieve pre-whirl regulation of centrifugal pump. During design process the trailing edge of vane is assumed as equal velocity moment condition, and the distribution of vane setting angle along meridional streamline is also given as a quartic function firstly, the camber line is then drawn by point-by-point integration method and thickened at both sides along circumferential direction. With local vortex dynamics diagnosis theory, the optimal improvement of vane space shape can be finished by adjusting the design parameters of vane setting angle distribution coefficient ap. The full flow passage numerical simulations of centrifugal pump with IGV device are completed to analyze the influence of pre-whirl regulation on hydraulic performance of centrifugal pump under various pre-whirl angles. The results show that the pre-whirl regulation can improve the hydraulic performance of centrifugal pump on off-conditions. Under the positive pre-whirl regulation conditions, the best efficient point shift to small flow rate zone, and under the negative pre-whirl regulation conditions it moves to large flow rate zone. Compared with the pump without IGV device at the same flow rate condition of 0.8Q (Q the design flow rate), the hydraulic efficiency of centrifugal pump with IGV device improves obviously and reaches up to 1.43%. Meanwhile compared with that installed with the straight vanes designed based on the traditional theory, the inner flow field of centrifugal pump with the designed vanes improves and the overall hydraulic efficiency of centrifugal pump is somewhat increased.

The relevance of xylem network structure for plant hydraulic efficiency and safety

2007 ◽  
Vol 247 (4) ◽  
pp. 788-803 ◽  
Author(s):  
Lasse Loepfe ◽  
Jordi Martinez-Vilalta ◽  
Josep Piñol ◽  
Maurizio Mencuccini
Keyword(s):  
Network Structure ◽  
Hydraulic Efficiency

scholarly journals Performance Improvement of a Liquid Molten Salt Pump: Geometry Optimization and Experimental Verification

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 423 ◽  
Author(s):  
Kai Wang ◽  
Xin Lu ◽  
Yu Li ◽  
Xianghui He ◽  
Houlin Liu ◽  
...  
Keyword(s):  
Molten Salt ◽  
Performance Improvement ◽  
Pressure Fluctuation ◽  
Geometry Optimization ◽  
Internal Flow ◽  
Experimental Methods ◽  
Sharp Corner ◽  
Hydraulic Efficiency ◽  
Low Velocity ◽  
Pump Performance

In order to enhance the hydraulic efficiency of a liquid molten salt pump, the improvement on the pump was carried out through numerical and experimental methods. The internal flow field obtained by the numerical simulation was analysed. The results show that there are low-velocity area in the scroll region and large curvature of the streamline at the outlet. Geometric modification was made by trimming the back-blades of the impeller and filleting the sharp corner of the outlet pipe. The modified pump performance was verified by the experiments. The hydraulic efficiency, the pressure fluctuation, vibration characteristics between the original and modified pump were compared. The results showed that the hydraulic efficiency of the modified pump increased 7.4%. In addition, the pressure fluctuation and vibration intensity were also reduced compared with the original pump. This result shows that the geometric modification improves not only the hydraulic performance but also the structural properties.

Experimental analysis on the hydraulic efficiency of mudflow breakers

2004 ◽  
pp. 385-392
Author(s):  
A Armanini ◽  
C Dalrì ◽  
F Della Putta ◽  
M Larcher ◽  
L Rampanelli ◽  
...  
Keyword(s):  
Experimental Analysis ◽  
Hydraulic Efficiency
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