A new approach for modeling and analysis of the lubricated piston skirt-cylinder system with multi-physics coupling

A novel U-shaped acoustic-manipulated design to enhance the performance of low-efficiency filters for sub-micron particles

A new solar mid-and-low temperature receiver/reactor with linear Fresnel reflector

The ability of ultrasound to produce highly controlled erosion phenomenon was investigated and various erosion models have been compared by considering various parameters. In cleaning industry, Vibro Cleaner (VC) has been used to remove contaminations from the surface of metal components. This process is most preferable to out of reach or critical surface of the objects. The novelty of this research is to compare various erosion models and to identify appropriate model for ultrasonic cleaning application to get meaningful results of metal removal rate. The computational model of Vibro Cleaner has been developed using pressure acoustic transient in COMSOL Multiphysics software. Acoustic and Computational Fluid Dynamics (CFD) modules have been coupled together to investigate erosion rate. In acoustic approach, acoustic pressure and sound pressure level have been studied by means of piezoelectric transducer through tank wall transience. In CFD approach, Bubbly fluid flow has been applied to get turbulence in acoustic streaming. Also, particle tracing has been coupled to understand the particle trajectories and motion of fluid flow. Erosion terms are also introduced at a surface of metal parts which need to be clean. The Erosion rate has been evaluated by using cavitation erosion phenomenon in which cavitation bubbles strike and implode over the metal surface and clean the dirt, dust, oil and other contaminations. Various Erosion models like Finnie, E/CRC, Oka and Det Norske Veritas (DNV) have been studied and results have been compared to identify appropriate erosion model towards the ultrasonic cleaning application by considering 28 kHz frequency and PZT-4 piezoelectric transducer. Comparative study leads to conclude that the Finnie erosion model have given stringent results as compare to other erosion model.

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Erosive investigation of various erosion models for vibro cleaner developed based on ultrasonic technique using COMSOL multiphysics

The tribo-dynamics performance of the piston–cylinder system is affected by multiple physical fields. The current work presents a novel multiphysics coupling method to model and analyze the lubricated piston skirt–cylinder interface considering the cylinder liner vibration. This method is implemented by coupling multibody dynamics of the crank-connecting rod–piston–cylinder system, the heat transfer of the cylinder and piston, hydrodynamics lubrication on the skirt–cylinder interface, vibration of the cylinder liner, and thermal as well as elastic deformation in the piston–cylinder system together with rheological characteristics of lubricating oil. The proposed method is adopted into a four-stroke gasoline engine to predict its dynamics and tribological characteristics, with the purpose of revealing the influence of cylinder liner vibration on the tribo-dynamics implementation of the piston–cylinder system. The results indicate that increasing the stiffness and damping coefficient of the cylinder is beneficial to suppress the vibration of the system, but it has little effect on the tribological characteristics of the piston skirt–cylinder interface.

/pdf/the-tribo-dynamics-performance-of-the-lubricated-piston-1n27rd9r.pdf

Vipulkumar Rokad

Papers

Development of 3D improved acoustic transient model for vibro cleaner using COMSOL multiphysics

Erosive investigation of various erosion models for vibro cleaner developed based on ultrasonic technique using COMSOL multiphysics