scholarly journals Numerical Simulation of Hydraulic Characteristics in A Vortex Drop Shaft

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1393 ◽  
Author(s):  
Wenchuan Zhang ◽  
Junxing Wang ◽  
Chuangbing Zhou ◽  
Zongshi Dong ◽  
Zhao Zhou
Keyword(s):  
Numerical Simulation ◽  
Cavitation Erosion ◽  
Flow Characteristics ◽  
Vertical Shaft ◽  
Hydraulic Characteristics ◽  
Drop Shaft ◽  
New Type ◽  
Velocity Pressure ◽  
Inflow Conditions ◽  
Shaft Wall

A new type of vortex drop shaft without ventilation holes is proposed to resolve the problems associated with insufficient aeration, negative pressure (Unless otherwise specified, the pressure in this text is gauge pressure and time-averaged pressure) on the shaft wall and cavitation erosion. The height of the intake tunnel is adjusted to facilitate aeration and convert the water in the intake tunnel to a non-pressurized flow. The hydraulic characteristics, including the velocity (Unless otherwise specified, the velocity in this text is time-averaged velocity), pressure and aeration concentration, are investigated through model experiment and numerical simulation. The results revealed that the RNG k-ε turbulence model can effectively simulate the flow characteristics of the vortex drop shaft. By changing the inflow conditions, water flowed into the vertical shaft through the intake tunnel with a large amount of air to form a stable mixing cavity. Frictional shearing along the vertical shaft wall and the collisions of rotating water molecules caused the turbulence of the flow to increase; the aeration concentration was sufficient, and the energy dissipation effect was excellent. The cavitation number indicated that the possibility of cavitation erosion was small. The results of this study provide a reference for the analysis of similar spillways.

Numerical Simulation and Model Test on Hydraulic Characteristics of Long-Distance Inverted Siphon

2012 ◽  
Vol 212-213 ◽  
pp. 1131-1135 ◽  
Author(s):  
Juan Li ◽  
Zhen Wei Mu ◽  
Lin Li
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Inlet Section ◽  
Hydraulic Characteristics ◽  
Filling Process ◽  
Long Distance ◽  
Three Dimensional Flow ◽  
Inverted Siphon

Make Use of three-dimensional flow field turbulence numerical simulation of unsteady flow k~εturbulence model and tracking the free surface VOF method of long-distance inverted siphon. By numerical calculation of flow characteristics and pressure distribution, carried out with the model test contrast, the results were coordinate and meet the requirements of design. But vortex formed in the filling process, it is recommended to optimize the inverted siphon inlet section. The method of combining calculation and test on the long-distance inverted siphon provide the reference for the design and operation.

Numerical Simulation of Heat Transfer Characteristics of Dimpled Plate

2012 ◽  
Vol 170-173 ◽  
pp. 2686-2692
Author(s):  
Chang Fa Ji ◽  
Xiao Bing Liu ◽  
Rui Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Heat Transfer Efficiency ◽  
New Type ◽  
The Impact

Designed a new type of plate heat exchanger-dimpled plate heat exchanger, then conducted a three-dimensional numerical simulation on flow, heat transfer and resistance characteristics of 15 kinds of different sizes dimpled plate heat exchangers by Fluent software，obtains the impact of the dimples geometric parameters such as dimple diameter, dimple spacing, dimple height on the heat transfer and flow characteristics. The results show that in different Reynolds number, dimple diameter, dimple spacing and dimple height on the effect of the dimple plate heat transfer efficiency is quite similar, and the impact becomes increasingly evident with the Reynolds numbers increasing. The combined effect of plate heat exchanger is best when dimple diameter, dimple spacing, dimple height are separately 12mm, 21mm, 4mm in the 15 kinds of different combination dimpled plates.

Numerical Simulation of the Two-Phase Flow in a New Type Cyclone

2011 ◽  
Vol 201-203 ◽  
pp. 263-266 ◽  
Author(s):  
Ning Ning Xing ◽  
Wei Lin Zhao
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Particle Trajectory ◽  
Swirling Flow ◽  
Flow Characteristics ◽  
Cement Plant ◽  
Phase Flow ◽  
Two Phase ◽  
New Type ◽  
Fluent Software

A new type cyclone with oblique top, transitional volute chamber, eccentric inner cylinders and sloping outlet were designed and manufactured by numerical analysis, which had been applied to the five-stage preheater in the cement plant with the capacity of 5000t/d. To simulate the gas flow field and particle trajectory in cyclone, the Fluent software was used, and the RNG k-ε model and discrete random walk model were proposed. The flow characteristics of gas-solid two-phase were analyzed. It is found that the strongly swirling flow occurs in the new type cyclone, and the particles of raw meal can be more efficiently separated from the gas.

scholarly journals Hydraulic Characteristics and Numerical Simulation of the Entrance Section of Ladder-Shaped Spillway

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
X. B. Gu ◽  
Q. H. Wu ◽  
Y. Wang ◽  
H. X. Zhao
Keyword(s):  
Numerical Simulation ◽  
Energy Dissipation ◽  
Dissipation Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Energy Dissipation Rate ◽  
Numerical Results ◽  
Experimental Results ◽  
Flow State ◽  
Hydraulic Characteristics

The ladder-shaped spillway in a certain reservoir junction is set as the engineering background in the paper. The hydraulic similarly model experiment and three-dimensional numerical simulation of hydraulic characteristics of water flow are performed. The outflow capacity, flow state analysis, velocity distribution, water surface line, pressure, and the energy dissipation rate are analyzed, and experimental results are compared with the numerical results. The conclusions demonstrate that the numerical results of the flow characteristics are very proximate to actual experimental results, the changeable law is the same, and their energy dissipation rate is basically consistent; it shows the feasibility of three-dimensional numerical simulation; the conclusions can provide the basis for the optimization about the flow state of the ladder-shaped spillway in the future.

3D Numerical Simulation of a New Type of Throttle Control Valve

2011 ◽  
Vol 215 ◽  
pp. 199-203
Author(s):  
San Pin Zhou
Keyword(s):  
Numerical Simulation ◽  
Flow Characteristics ◽  
Control Valve ◽  
Hydraulic Pressure ◽  
Valve Design ◽  
Controlling System ◽  
Simulation Calculation ◽  
New Type ◽  
And Performance ◽  
Liquid Movement

According to the requirements of hydraulic pressure controlling system of the State 863 Plan of China: “the development of cased hole twin packer cell”, a new type of two-way valve used in the hydraulic pressure controlling system of downhole tester was developed, which could control the direction of liquid movement. The valve has not only the sealing function of seal valve, but also the adjustment function of the rate of flow of throttle valve. It is different from the ordinary two-way valve in structure because of its particular demands of function and performance. In this paper, a study was carried out on the flow field and flow characteristics in the throttle control valve by means of hydromechanics numerical simulation and with the resulting analysis, structural optimization was performed to the throttle control valve. The result that obtained by simulation calculation can provide theoretic reference for the valve design.

Study on the Flow Characteristics of Shengli Oilfield Super Heavy Oil

2017 ◽  
Vol 10 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Wang Shou-long ◽  
Li Ai-fen ◽  
Peng Rui-gang ◽  
Yu Miao ◽  
Fu Shuai-shi
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Heavy Oil ◽  
Flow Characteristics ◽  
Fluid Viscosity ◽  
Linear Flow ◽  
Start Up ◽  
Non Linear ◽  
Core Permeability ◽  
Velocity Pressure

Objective:The rheological properties of oil severely affect the determination of percolation theory, development program, production technology and oil-gathering and transferring process, especially for super heavy oil reservoirs. This paper illustrated the basic seepage morphology of super heavy oil in micro pores based on its rheological characteristics.Methods:The non-linear flow law and start-up pressure gradient of super heavy oil under irreducible water saturation at different temperatures were performed with different permeable sand packs. Meanwhile, the empirical formulas between start-up pressure gradient, the parameters describing the velocity-pressure drop curve and the ratio of gas permeability of a core to fluid viscosity were established.Results:The results demonstrate that temperature and core permeability have significant effect on the non-linear flow characteristics of super heavy oil. The relationship between start-up pressure gradient of oil, the parameters representing the velocity-pressure drop curve and the ratio of core permeability to fluid viscosity could be described as a power function.Conclusion:Above all, the quantitative description of the seepage law of super heavy oil reservoir was proposed in this paper, and finally the empirical diagram for determining the minimum and maximum start-up pressure of heavy oil with different viscosity in different permeable formations was obtained.

scholarly journals Numerical and Experimental Study of Lightning Stroke to BIPV Modules

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Lightning Stroke ◽  
Study Results ◽  
Pv Modules ◽  
New Type ◽  
Metal Frame ◽  
Current Flows

Building Integrated Photovoltaic (BIPV) modules are a new type of photovoltaic (PV) modules that are widely used in distributed PV stations on the roof of buildings for power generation. Due to the high installation location, BIPV modules suffer from lightning hazard greatly. In order to evaluate the risk of lightning stroke and consequent damage to BIPV modules, the studies on the lightning attachment characteristics and the lightning energy withstand capability are conducted, respectively, based on numerical and experimental methods in this paper. In the study of lightning attachment characteristics, the numerical simulation results show that it is easier for the charges to concentrate on the upper edge of the BIPV metal frame. Therefore, the electric field strength at the upper edge is enhanced to emit upward leaders and attract the lightning downward leaders. The conclusion is verified through the long-gap discharge experiment in a high voltage lab. From the experimental study of multi-discharge in the lab, it is found that the lightning interception efficiency of the BIPV module is improved by 114% compared with the traditional PV modules. In the study of lightning energy withstand capability, a thermoelectric coupling model is established. With this model, the potential, current and temperature can be calculated in the multi-physical field numerical simulation. The results show that the maximum temperature of the metal frame increases by 16.07 °C when 100 kA lightning current flows through it and does not bring any damage to the PV modules. The numerical results have a good consistency with the experimental study results obtained from the 100 kA impulse current experiment in the lab.

Sublimation of composite ice and its influence on performance of ice shells

2021 ◽  
Vol 36 (1) ◽  
pp. 67-77
Author(s):  
Yue Wu ◽  
Junkai Huang ◽  
Jiafeng Chen
Keyword(s):  
Numerical Simulation ◽  
Shell Structure ◽  
Composite Shell ◽  
Engineering Practice ◽  
Sublimation Rate ◽  
Long Span ◽  
Static Performance ◽  
New Type ◽  
Ice Sublimation ◽  
Composite Shell Structure

The long-span ice composite shell structure is a new type of ice and snow structure developed in recent years. The engineering practice of ice composite shell shows that sublimation is one of the important reasons for its damage and even collapse. In this paper, we firstly supplemented the existing H-K equation and obtained the revised ice sublimation equation through indoor evaporative plate experiment considering the influence of admixtures and wind speed. Afterwards, combining the simulations of solar radiation and CFD, the numerical simulation of sublimation distribution on the surface of were realized by programming in Grasshopper platform. During sublimation, the thickness of the ice composite shell decreases by 0.38 mm every 10 days and the sublimation rate on the sunny side was 1.7 times that on the shady side. Finally, the static performance and stability of the sublimated ice composite spherical shell were analyzed. After 70 days of sublimation, the thickness of the ice composite shell structure becomes thinner and uneven, which leads its sensitivity to external load increases.

Numerical Simulation Study on Cooling Characteristics of a New Type of Film Hole

2020 ◽  
Author(s):  
Chunhai Guo ◽  
Bin Wang ◽  
Zhenya Kang ◽  
Wenwu Zhang ◽  
Huilong Zheng
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
New Type
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