Estimating Hydrodynamic Characteristics of Sediment Exclusion Labyrinth Weir Using 3D Numerical Analysis

2015 ◽  
Vol 15 (2) ◽  
pp. 277-283
Author(s):  
Sooyoung Kim ◽  
Kwang Hyun Ryu ◽  
Hong Taek Kim ◽  
Seung Oh Lee
2020 ◽  
Author(s):  
Bendaoud Nadia ◽  
Mehala Kadda

Hydrodynamic bearing are components that provide the guiding in rotation of rotating machines, such as turbines, the reactors. This equipment works under very severe operating conditions: high rotational speed and high radial load. In order to improve the hydrodynamic performance of these rotating machines, the industrialists specialized in the manufacture of hydrodynamic journal bearings, have designed a bearing model with its textured interior surface. The present work is a numerical analysis, carried out to observe the effect of a turbulent fluid flow in a non-textured and textured plain bearing and to thus to see the improvement of the hydrodynamic and tribological performances to a non- textured and textured surface of the plain bearing, under severe operating parameters. The rotational velocity varies from 11,000 to 21,000 rpm and radial load ranging from 2000 N to 9000 N. The numerical analysis is performed by solving the continuity equation of Navier-Stocks, using the finite volume method. The numerical results show that the most important hydrodynamic characteristics such as pressure, flow velocity of the fluid, friction torque, are significant for the textured plain bearing under rotational velocity of 21,000 rpm and radial load 10,000 N compared to obtained for a non-textured plain bearing.


Author(s):  
Bendaoud Nadia ◽  
Mehala Kadda

Hydrodynamic plain bearings are components that provide the guiding in rotation of rotating machines, such as turbines, the reactors. This equipment works under very severe operating conditions. In order to improve the hydrodynamic performance of these rotating machines, the industrialists specialized in the manufacture of hydrodynamic bearings have designed a bearing model with its textured interior surface. The numerical analysis is carried out to study the for both plain bearings types with a textured a non-textured surface thus to see the improvement of the plain bearing hydrodynamic performances, as well as the fluid flow behavior in motion. The analysis is performed by solving the continuity equation of Navier-Stokes, by the finite volume method, using CFD code. The numerical results show that the most important hydrodynamic characteristics such as pressure, minimal film thickness, friction torque, leakage flow, are significant for the textured plain bearing under rotational velocity of 6000rpm and radial load 10000N compared to obtained for a non-textured plain bearing.


2012 ◽  
Vol 19 (2) ◽  
pp. 17-24 ◽  
Author(s):  
Hassan Ghassemi ◽  
Amin Mardan ◽  
Abdollah Ardeshir

Numerical Analysis of Hub Effect on Hydrodynamic Performance of Propellers with Inclusion of PBCF to Equalize the Induced Velocity In this article the boundary element method (BEM) is applied to analyze the propeller hub as a non-lifting body and the blades in its vicinity as lifting bodies. In solver, the geometrical modeling of hub, blades are PBCF (Propeller Boss Cap Fin) constructed by quadrilateral elements. The velocity potential is determined on each element by discretized boundary integral equation. Iterative procedure is used to consider the adjacent body effect. In each step the body was independently analyzed with the influence of near body considered in inflow velocity. The induced velocity of propeller was calculated with and without PBCF in downstream. PBCF, an energy-saving device, reduces and uniforms the induced velocity of propeller in downstream. Numerical results of propeller hydrodynamic characteristics including hub effect, induced velocities, PBCF influence are presented.


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2015
Author(s):  
Ren ◽  
Hua ◽  
Ji

When a planing boat sails at the free surface, the posture changes drastically with time, so the surface piercing propellers usually work in oblique flow. In this paper, numerical simulations are performed to predict the performance of PSP-841B with Unsteady Reynolds Averaged Navier–Stokes (URANS) method coupling with sliding mesh and volume of fluid (VOF) method. The results show that the predicted thrust and torque coefficients of PSP-841B are in good agreement with the experimental data. It proves the present numerical schemes are feasible and validated. These schemes are applied in the simulations of SPP-1 that is installed to a planing craft. In oblique flow, the ventilation volume of SPP-1 increases dramatically, resulting in the postponed transition of vented status that changes from the fully dry to partially wetted; at the low advance ratios, the thrust and torque coefficients are less than that in the horizontal case. As the advance speed increases, the vented mode of SPP-1 varies from full ventilation to partially wet, and the forces and moments get closer to the results in the horizontal flow. In addition, the blockage effect of air cavity to the inflow in oblique flow is more significant than the results in the horizontal case.


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