Effect of Fluid Chemistry on the Consolidation and Hydraulic Conductivity of Sand-Clay Liners

The clay swelling potential of sand-clay liners exposed to saline water or specific chemicals can influence their hydraulic conductivity and other consolidation properties. The effect of saline water or chemicals on the sand-clay liners was thus studied and evaluated. The consolidation characteristics of the sand-clay liner can be different when tested under different fluid media. Bentonite and cement grouts are chemicals that have a significant effect on the sand-clay liners. Cement and bentonite can be used to seal off the openings within the liner to repair a defect or a malfunction. In this study, Al-Qatif clay was used to form a sand-clay liner when mixed with fine-grained sand (clay is 20% by dry weight). Soil samples extracted from this liner were exposed to inorganic chemical solutions. NaCl and CaCl2 solutions with concentration ranges of 0.1%, 0.5%, and 1.5% were used. Acidic water with pH values of 4, 5, and 6 was similarly used as fluid media. The effects of NaCl, CaCl2, and water with different acidity on the consolidation characteristics and hydraulic conductivity were obtained and compared to those of the distilled water. The effects of grout materials containing bentonite (1%, 2%, and 3% by weight) and cement (2.5%, 5%, and 7.5% by weight) were also investigated. The addition of bentonite grout to the liner surface was found to improve its hydraulic conductivity. The cement effect on the compressibility was found to be very significant. The findings of this study can serve as a guide for selecting parameters in the design and assessment of sand-clay liners in semi-arid regions and coastal zones.

Fabrication and Testing of Bioinspired Surface Designs for Friction Reduction at the Piston Ring and Liner Interface

The piston ring and liner interface is a major source of friction loss in automotive combustion engines. This loss can be mitigated by learning from surfaces from nature that manipulate friction. In this study, novel fabrication and testing methods were developed and used to efficiently compare 3D bioinspired surface designs to existing piston liner surface topographies. Surface designs inspired by frog toes were fabricated using two-photon lithography, and their frictional performance is compared to that of typical piston liner topography. These designs reduce surface friction by an average of 18%, and up to 39%, compared to a flat control. The developed fabrication and testing methods allow comparison with existing topographies without needing to transfer the designs to the original materials and provide an efficient approach for designing surfaces to meet the frictional challenges of the future.

Canvitation deterioration of diesel power plant cylinder liner

The generating station in which diesel engine is used as a prime mover for generating electrical energy is known as diesel power plant. The cylinders liner are cylindrical component that are fixed inside the engine block. The function of the cylinder liners is to retain the working fluid and to guide the piston. Most diesel power plant uses wet-cylinder liners that are exposed to intensive cavitation. The paper aimed at studying the behavior of the cylinder liners that can lead to cavitation. The analysis involves, modeling and simulation in using Solidworks Software. The analysis shows that the cylinders are subjected to harmonic vibration resulting to momentary separation of the coolant from the cylinder wall, creating a pressure difference around the coolant surface which forms air bubbles. These bubbles explode at an extreme velocity. The explosion of these bubbles release surface energy known as cavitation. The energy hammers the cylinder liner surface thereby removing minute particles of metal from the surface of the vibrating cylinder leading to cavitational deterioration. The paper hereby calls on automotive designers to take critical measures in designing of; cylinder liner, water jacket and the entire cooling system, in order to control this phenomenon.

Femtosecond Pulsed Ti:Sapphire Laser-Assisted Surface Texturing on Piston Ring and Its Tribology Characterization

Femtosecond laser-assisted surface texturing of compression piston rings is proposed and demonstrated. A femtosecond pulsed Ti3+:sapphire laser is used to generate dimples of the same size but with different area density on a moly-chrome ceramic deposited cast iron piston ring. The influence of the surface morphology and tribology operating conditions, such as reciprocating frequency and temperature of the lubricant, on friction and wear characteristics of textured piston rings and plateau honed liner samples is investigated. A decrease in the friction coefficient is observed with the texturing of rings. The dimple area density, which is defined as the ratio of the total textured area and the total area of the surface, of 16% and 27% offered a reduced coefficient of friction and minimize wear on the liner surface.

The effect of liner surface texture on journal bearing performance under thermo-hydrodynamic conditions

Purpose The purpose of this paper is to study the effect of liner surface texture on journal bearing performance. Modeling the profile curvature of the dimples or grooves is planned for different cases of texture surface under thermo-hydrodynamic condition (THD). The aim of this paper is to determine the effect the texture surface on the performance of journal bearing and specify the optimum shape for texture dimples. Design/methodology/approach The paper was opted for an exploratory study by applying finite difference method to solve the energy equation, the heat conduction equations and the Reynolds equation numerically. The lubricant film thickness is divided to a mesh of 640,000 points. The equations were solved for each point of the mesh by using a MATLAB code. For texture shape optimization, 24 cases of different texture shapes were selected which includes elliptical, triangle and square curvature shape. Findings The paper provides theoretical insights about the effect of texture shape on journal bearing performance. It was concluded that to get a high load-carrying capacity, the direction of curvature is preferably to be perpendicular to the sliding direction. The convex texture has higher load carrying capacity than concave texture. Finally, the surface with textures in channel form yields better overall performance than the surface with several dimples. Originality/value This paper fulfils an identified need to study how texture surface affects the performance of journal bearing under thermo-hydrodynamic conditions.