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Vane Geometry Effect on Lubrication Conditions between Vane Tip and Cam-Ring in Hydraulic Vane Machines
Mohamed Elashmawy,
Abdulaziz Alghamdi
Issue:
Volume 3, Issue 1-2, January 2015
Pages:
1-10
Received:
15 November 2014
Accepted:
19 November 2014
Published:
24 November 2014
Abstract: Vane geometry is an important parameter affecting the lubrication conditions of hydraulic vane machines. A simple thermo-elasto-hydrodynamic lubrication (TEHL) model was used to calculate the friction between vane tip and cam-ring of the hydraulic vane machines. Effect of vane geometry and its dimensions on hydraulic vane machines was theoretically investigated. Navier-Stokes and energy equations were numerically solved using finite difference technique. Viscosity and density distributions were considered in the TEHL-model. Results show that vane geometry optimization is quite important to enhance lubrication conditions of hydraulic vane machines. The study shows that the straight vane geometry is the best choice for high pressure applications. At higher values, increasing of vane tip radius of curvature and vane thickness enhances lubrication conditions between vane tip and cam-ring. Vane tip radius of curvature and vane thickness should not be less than 2 mm and 1.5 mm respectively.
Abstract: Vane geometry is an important parameter affecting the lubrication conditions of hydraulic vane machines. A simple thermo-elasto-hydrodynamic lubrication (TEHL) model was used to calculate the friction between vane tip and cam-ring of the hydraulic vane machines. Effect of vane geometry and its dimensions on hydraulic vane machines was theoretically...
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Developed Design for Line Bleeding Injection Pump: Double-Act LBIP
Mohamed Elashmawy,
Mohammad Alnais
Issue:
Volume 3, Issue 1-2, January 2015
Pages:
11-16
Received:
25 October 2014
Accepted:
30 October 2014
Published:
25 November 2014
Abstract: Injection process is essential for many industrial applications especially in water desalination and water treatment market. The new concept of injection, line bleeding injection pump (LBIP) [8], opens a door for injection processes of simpler and effective injection facilities with relatively low cost and less maintenance requirements. The concept of LBIP is to utilize the pressure inside the line and intensify it to produce higher pressure than the line pressure to inject chemicals inside it. Certain amount of water should be bleed out from the line. The amount of bleed water then could be either recycled back to the line or drained back to the intake. The aim of this study is to develop LBIP design to be double act injection pump. Double-act LBIP design is promising to be more effective and low price design for relatively higher doses injection applications. It has no spring. The developed design will act as two pumps in one unit using very simple design and traditional materials. This concept will take the cost to its minimum value. The double-act LBIP price is promising to be very competitive compared to other injection pump types. Double-act LBIP is equipped with 3 adapters as a simple and accurate variable displacement facility that gives the design a strong potential as metering injection pump with wide range of injection ability (20-1000 liter/day). Both single-act and double-act LBIP designs require no driving power except for the line pressure itself. This concept is promising for researches of developing renewable energy with seawater desalination units in remote areas.
Abstract: Injection process is essential for many industrial applications especially in water desalination and water treatment market. The new concept of injection, line bleeding injection pump (LBIP) [8], opens a door for injection processes of simpler and effective injection facilities with relatively low cost and less maintenance requirements. The concept...
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Design of Swashplate Axial Piston Machines Having Low Piston Transverse Forces
Issue:
Volume 3, Issue 1-2, January 2015
Pages:
17-23
Received:
22 November 2014
Accepted:
25 November 2014
Published:
27 December 2014
Abstract: Axial piston machine of swashplate type is the common design widely used for many hydraulic applications because of its simplicity, compact design and low cost. However, this simplicity has a negative effect for piston transverse forces which limits machine performance. The main target of this study is to investigate a feasible design of a fixed displacement swashplate contour in order to minimize piston transverse forces. The design should compensate the contact surface mechanism between swasplate and piston end. Piston slipper is replaced by a ball that is rotatably mounted within a ball socket formed at the piston end. The ball runs on a circumferential contour groove formed on the swashplate surface. The sliding friction between swashplate and slipper is replaced by a rolling friction between ball and circumferential runway groove. Primary results show a rough estimation of 30% reduction of piston transverse forces due to the cam action radial forces elimination. This reduction promises to enhance overall machine performance.
Abstract: Axial piston machine of swashplate type is the common design widely used for many hydraulic applications because of its simplicity, compact design and low cost. However, this simplicity has a negative effect for piston transverse forces which limits machine performance. The main target of this study is to investigate a feasible design of a fixed di...
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Computer Aided Design of Axial Piston Machines Having a Roller Piston Bearing
Mohamed Elashmawy,
Abdulaziz Alghonamy,
Isam Elbadawi
Issue:
Volume 3, Issue 1-2, January 2015
Pages:
24-29
Received:
24 November 2014
Accepted:
26 November 2014
Published:
27 December 2014
Abstract: Swashplate axial piston machines are simple, compact and low price. This simplicity is at the expense of piston transverse forces which limits machine characteristics. The aim of this study is to propose more effective developed design using roller piston bearing. Ball bearing was proposed to reduce transverse forces acting on the piston end of the axial piston machines. The proposed roller bearing design will provide line contact bearing between roller and cam contour compared to point contact of ball bearing arrangement. The roller runs on a flat surface contour formed on the swashplate which is simpler in manufacturing process. The sliding friction between swashplate and slipper is replaced by a rolling friction between roller and runway of cam surface contour. Results show the feasibility of the developed design. The proposed design promises to increase the pressure limitation of the ball bearing arrangement. Parameters such as piston displacement, cam action angle are the same for both roller and ball piston bearing. A comparison analysis was also performed between two alternative cam contours, sinusoidal and linear piston displacement. The selection criterion was based on piston transverse torque. Results show that sinusoidal piston displacement is much better choice than the linear one.
Abstract: Swashplate axial piston machines are simple, compact and low price. This simplicity is at the expense of piston transverse forces which limits machine characteristics. The aim of this study is to propose more effective developed design using roller piston bearing. Ball bearing was proposed to reduce transverse forces acting on the piston end of the...
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