Numerical Simulation of Relationship Between Flow Pattern and Hydraulic Performance of Tubular Pump

2011 ◽  
Author(s):  
Li Cheng ◽  
Can Luo ◽  
Chao Liu
Keyword(s):  
Flow Pattern ◽  
Reference Frames ◽  
Static Pressure ◽  
Leading Edge ◽  
Flow Patterns ◽  
Hydraulic Performance ◽  
Hydraulic Loss ◽  
Pump System ◽  
Water Transportation ◽  
The Relationship

The bulb tubular pump had advantages of large capacity and low head. This type of pump has been widely used for water transportation project or irrigation and drainage. Nowadays China East Routine of South-to-North Water Transfers Project partly uses bulb tubular pumping station. In order to study the relationship between the flow pattern and hydraulic performance of bulb tubular pump system, the SIMPLEC algorithm, based on the RNG k-ε model with Wall-Function Law, is applied for the solution of the discretization governing equation. Using multiple reference frames, the flow detail of whole pumping system was attained. The calculation results were agreement with the test ones. The flow patterns of different operating point were analyzed. There were large eddy areas in the inlet of blades when pump systems were operated in small flowrates. The flow patterns of BEP (Best Efficiency Point) and large flowrate were good. The static pressure of suction face of leading edge was low and the static pressure of pressure face of leading edge was highest during BEP and small flowrate point. There were part low static pressure areas of leading edge of pressure surface and part high static pressure area of leading edge of suction surface during large flowrate point. The relationship between hydraulic loss of bulb of tubular pump and flowrate depended on the operating points and did not follow the quadratic law of traditional pipe. The optimal design of turbular pump should be mainly focused on the flow pattern of blades and guided vanes.

scholarly journals Flow Pattern Map of Flow Boiling in a Rectangular Channel Filled with Porous Media

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2440
Author(s):  
Youngwoo Kim ◽  
Dae Yeon Kim ◽  
Kyung Chun Kim
Keyword(s):  
Porous Media ◽  
Flow Pattern ◽  
Flow Regime ◽  
Annular Flow ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Flow Patterns ◽  
Flow Pattern Map ◽  
Mist Flow ◽  
Churn Flow

A flow visualization study was carried out for flow boiling in a rectangular channel filled with and without metallic random porous media. Four main flow patterns are observed as intermittent slug-churn flow, churn-annular flow, annular-mist flow, and mist flow regimes. These flow patterns are clearly classified based on the high-speed images of the channel flow. The results of the flow pattern map according to the mass flow rate were presented using saturation temperatures and the materials of porous media as variables. As the saturation temperatures increased, the annular-mist flow regime occupied a larger area than the lower saturation temperatures condition. Therefore, the churn flow regime is narrower, and the slug flow more quickly turns to annular flow with the increasing vapor quality. The pattern map is not significantly affected by the materials of porous media.

scholarly journals The Influence of Bulb Position on Hydraulic Performance of Submersible Tubular Pump Device

2021 ◽  
Vol 9 (8) ◽  
pp. 831
Author(s):  
Zhuangzhuang Sun ◽  
Jie Yu ◽  
Fangping Tang
Keyword(s):  
Entropy Production ◽  
Large Scale ◽  
Experimental Testing ◽  
Guide Vane ◽  
Outer Wall ◽  
Hydraulic Performance ◽  
Hydraulic Loss ◽  
Optimized Design ◽  
Outlet Channel ◽  
Wall Area

In order to study the influence of the position of the bulb on the hydraulic performance of asubmersible tubular pump device, based on a large-scale pumping station, two schemes—involving a front-mounted bulb and a rear-mounted bulb, respectively—were designed. The front-mounted scheme uses the GL-2008-03 hydraulic model and its conventional guide vane, while the rearmounted scheme uses the optimized design of a diffuser vane. The method of combining numerical simulation and experimental testing was used to analyze the differences between the external and internal characteristics of the two schemes. The results show that, under the condition of reasonable diffusion guide vane design, the efficiency under the rear-mounted scheme is higher than that under the front-mounted scheme, where the highest efficiency difference is about 1%. Although the frontmounted bulb scheme reduces the hydraulic loss of the bulb section, the placement of the bulb on the water inlet side reduces the flow conditions of the impeller. Affected by the circulation of the guide vane outlet, the hydraulic loss of the outlet channel is greater than the rear-mounted scheme. The bulb plays a rectifying function when the bulb is placed behind, which greatly eliminates the annular volume of the guide vane outlet, and the water outlet channel has a smaller hydraulic loss. In the front-mounted scheme, the water flow inside the outlet channel squeezes to the outer wall, causing higher entropy production near the outer wall area. The entropy production of the rear-mounted scheme is mainly in the bulb section and the bulb support. This research can provide reference for the design and form selection of a submersible tubular pump device, which has great engineering significance.

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2003 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Micro Channels

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406 × 2.032 mm cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal that the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Annual flow is identified as the dominant flow pattern for conditions relevant to two-phase micro-channel heat sinks, and forms the basis for development of a theoretical model for both pressure drop and heat transfer in micro-channels. Features unique to two-phase micro-channel flow, such as laminar liquid and gas flows, smooth liquid-gas interface, and strong entrainment and deposition effects are incorporated into the model. The model shows good agreement with experimental data for water-cooled heat sinks.

scholarly journals Footprints of a flapping wing

2017 ◽  
Vol 818 ◽  
pp. 1-4 ◽  
Author(s):  
Jun Zhang
Keyword(s):  
Flow Pattern ◽  
External Force ◽  
Thrust Force ◽  
Flow Patterns ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Left Behind ◽  
Full Picture

Birds have to flap their wings to generate the needed thrust force, which powers them through the air. But how exactly do flapping wings create such force, and at what amplitude and frequency should they operate? These questions have been asked by many researchers. It turns out that much of the secret is hidden in the wake left behind the flapping wing. Exemplified by the study of Andersen et al. (J. Fluid Mech., vol. 812, 2017, R4), close examination of the flow pattern behind a flapping wing will inform us whether the wing is towed by an external force or able to generate a net thrust force by itself. Such studies are much like looking at the footprints of terrestrial animals as we infer their size and weight, figuring out their walking and running gaits. A map that displays the collection of flow patterns after a flapping wing, using flapping frequency and amplitude as the coordinates, offers a full picture of its flying ‘gaits’.

scholarly journals Suspended sediment distribution under varied currents in the largest river-connected lake of China

2017 ◽  
Vol 18 (3) ◽  
pp. 994-1004 ◽  
Author(s):  
Hua Wang ◽  
Yijun Zhao ◽  
Fengnian Zhou ◽  
Huaiyu Yan ◽  
Yanqing Deng ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Suspended Sediment ◽  
Flow Patterns ◽  
Field Investigation ◽  
Gravity Flow ◽  
Shear Stresses ◽  
Sediment Distribution ◽  
Back Flow ◽  
The North ◽  
Dry Seasons

Abstract Poyang Lake was selected as the research area. Based on laboratory experiment, field investigation and numerical simulation, the spatial distributions of suspended sediment (SS) under the gravity-flow, jacking-flow and back-flow patterns were quantitatively analysed. An annular flume experiment was conducted to determine the critical starting shear stresses of the sediments in the flood and dry seasons. By numerical experiment, the SS transport under different flow patterns was explored. Several results stand out. (1) The critical starting shear stresses of the sediments in the flood and dry seasons were 0.35 N·m−2 and 0.29 N·m−2, respectively. (2) Due to the strongest flow disturbance and scouring effect, SS under the gravity-flow pattern was characterized by the highest loads. The lowest SS was observed during the jacking-flow pattern, which could be attributed to the lowest water level gap between the lake and external rivers. The loads ranged from 0.053 kg·m−3 to 0.068 kg·m−3. (3) Under the back-flow pattern, SS in the north lake was evidently influenced by the Yangtze River, and the mean value was approximately 0.12 kg·m−3. With the gradually weakened back-flow impact, the SS load was decreased from the north to the middle of the lake.

Solution of Levi Civita’s Problem by Infinite Matrix Inversion

1973 ◽  
Vol 40 (1) ◽  
pp. 31-36 ◽  
Author(s):  
M. Bentwich
Keyword(s):  
Flow Pattern ◽  
Flow Direction ◽  
Leading Edge ◽  
Arbitrary Cross Section ◽  
Matrix Inversion ◽  
Infinite Matrix ◽  
Algebraic Equations ◽  
Flow Past ◽  
Linear Algebraic Equations ◽  
Wet Surface

The author proposes a new method by which one can solve for the two-dimensional irrotational fully cavitating flow past a cylinder of arbitrary cross section. Unlike the available solutions, it is in the form of two expansions each valid in part of the complex potential plane w = Φ + iΨ. The a priori unknown coefficients in the two expansions are linked by infinitely many linear algebraic equations. By inverting the associated matrix and utilizing the boundary condition, that represent the geometry of the wet surface, the coefficients in the expansions are evaluated and the solution is completed. Cases in which the wet surface is circular, the pressure along the free streamlines is constant, and the entire flow pattern is symmetric with respect to flow direction at infinity are considered in detail. Also, the well-known solution for the flow past a flat plate is compared to that obtained by the method of matrix inversion. Judging from these results, the convergence of the series appears to be very rapid. The author finally discusses the applicability of the method to cases in which the obstacle has a sharp leading edge, the pressure in the cavity is not uniform, or the flow pattern is not symmetric.

The Influence of Wrap Angle of Blade on the Internal Flow Field and Hydraulic Performance of Double Suction Pump

2018 ◽  
Author(s):  
Hao Chang ◽  
Weidong Shi ◽  
Wei Li ◽  
Jianrui Liu ◽  
Ling Zhou ◽  
...  
Keyword(s):  
Flow Field ◽  
Cross Section ◽  
Turbulence Model ◽  
Static Pressure ◽  
Internal Flow ◽  
Hydraulic Performance ◽  
Optimal Model ◽  
Suction Pump ◽  
External Characteristic ◽  
Wrap Angle

In order to study the influence rule of wrap angle of blade on the internal flow field and hydraulic performance of double suction pump, 5 kinds of wrap angles of blade with 100°, 110°, 120°, 130° and 140° are designed in this paper. The turbulence model and the grid type are analyzed, the performance of ES350-575 double suction pump is obtained by employ the software CFX. The static pressure and velocity distributions in the cross-section are analyzed. Therefore, the optimal model is obtained, and the relevant external characteristic test is conducted. The result shows that the reasonable increase of the wrap angle of blade can enhance the performance of the pump effectively, which can improve the static pressure and velocity distributions of the internal flow field.

Flow patterns of vertical plane thermal buoyant jet in shallow water

2018 ◽  
Vol 32 (12n13) ◽  
pp. 1840041
Author(s):  
Li-Qing Zhao ◽  
Jian-Hong Sun ◽  
Yang Lu
Keyword(s):  
Flow Pattern ◽  
Vertical Plane ◽  
Free Water ◽  
Simulation Method ◽  
Boussinesq Approximation ◽  
Flow Patterns ◽  
Buoyant Jet ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Impinging Flow

A heated plane water jet impinging vertically onto free water surface has been numerically studied based on large eddy simulation method coupled with the volume of fluid approach. The Boussinesq approximation is adopted to simulate the effect of buoyancy. Results showed that there exist two flow patterns for the plane thermal buoyant jet, which are the stable impinging flow pattern and the flapping impinging flow pattern. Distinct temperature stratification can be found in the stable impinging flow pattern, while it disappears in the flapping impinging flow pattern.

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