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Investigation of Fluid Flow in Grinding using LDA Techniques and CFD Simulation

Wu, H (2009) Investigation of Fluid Flow in Grinding using LDA Techniques and CFD Simulation. Doctoral thesis, Liverpool John Moores University.

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Abstract

This research aimed to establish the requirements for effective fluid flow in grinding and to improve the efficiency of the fluid delivery system (fluid delivery optimization). Highly efficient fluid delivery will lower grinding temperatures, reduce the risk of thermal damage and reduce wheel wear. The thesis describes the work completed in the investigation of the complex fluid flow that occurs in the region close to the grinding contact zone between the wheel and workpiece and the boundary layer phenomena around the periphery of the rotating grinding wheel. Studies on air scraper and shoe nozzle application are also presented. Laser Doppler Anemometry (LDA) was employed to obtain a basic understanding of the flow velocity profile in the region close to the grinding contact zone in a low speed grinding system and key characteristics of the fluid flow under varying grinding conditions were identified. The mathematical formulae describing the air velocity distribution around the wheel have been derived from theory based on Newton's laws. Air boundary layer flow around the rotating grinding wheel was studied using LDA measurements and Computational Fluid Dynamics (CFD) simulation to get the air velocity distribution in varying conditions. The experimental results and the investigation made clear the contradictory knowledge relative to this issue and gave a full understanding of the air boundary layer flow. Air scrapers are used to reduce the effects of the air boundary layer. The effects of the size and position of the different scrapers on the air flow velocity and pressure distribution was investigated using CFD simulation. The research work provides a comprehensive assessment of the ability of the air scraper to reduce the intensity of the air boundary layer. The upper surface of the shoe nozzle can be regarded as an air scraper used to interrupt the air flow. Three different shoe nozzles were applied to investigate the fluid delivery situation using CFD simulation. Results from preliminary studies are presented for the shoe nozzle application. The effects of input fluid velocity, gap size and wheel speed on the pressure distribution along the arc of the gap are reported.

Item Type: Thesis (Doctoral)
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TJ Mechanical engineering and machinery
Divisions: General Engineering Research Institute
Date Deposited: 15 Mar 2017 10:31
Last Modified: 15 Mar 2017 10:31
URI: http://researchonline.ljmu.ac.uk/id/eprint/5944

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