www.nottingham.ac.uk/complex-systems/index.aspx

Supervisors: The project will be jointly supervised by three researchers:

-  Professor Axinte in the Faculty of Engineering
-  Dr Hao in the Faculty of Science and Engineering
-  Professor Billingham in the School of Mathematical Sciences 

Cutting fluid plays a vital role in machining processes such as drilling, grinding, milling and turning. The main purposes of the cutting fluid are: to reduce friction between tool and work piece; to limit and dissipate any heat generated; to flush away chips from the machining process. The cutting fluid is often supplied as a jet through a nozzle, so the position, orientation and geometry of the nozzle, as well as rate of supply of fluid, need to be well optimized to achieve high removal rates and good workpiece quality in machining processes. The use of cutting fluid does, however, have significant negative effects. For example, it usually contains carcinogens that pose serious health risks for machine operators. In addition, the delivery of cutting fluid can account for more than 15% of manufacturing costs. 

In this PhD project, the student will develop a lubrication model for the flow in the grinding zone. Due to the random position and protrusion of the abrasives from the theoretical wheel geometry, there is a thin zone of varying thickness, typically <100μm, across the width of the wheel where fluid is forced into the cutting zone to lubricate and cool the workpiece; this zone will be modelled as a rapidly moving porous medium. Rational approximation methods, such as the method of matched asymptotic expansions, will be used to derive simplified equations that relate the flowrate and composition of the multiphase cutting fluid/air mixture to the parameters of the system. In particular since, on the lengthscale of the jet and the exterior fluid flow, the thickness of the grinding region is negligible, we aim to formulate a boundary condition that can provide a link between the exterior flow and the flow in the grinding zone, thereby allowing costly CFD calculations to be focussed on the lengthscale of the exterior flow, where it can be used effectively.

To validate this work we will perform Laser Doppler Anemometry measurements using a transparent (glass) enclosure and workpiece to enable the visualisation the distribution of the fluid around and within the cutting zone; additionally grinding wheels with different porosities and geometries will be tested to validate the models towards industrial utilisation. 

Summary: UK students - Tuition Fees paid, and full Stipend of £13,863 (2014/15 rate), EU students Tuition Fees paid.

Eligibility: applicants will need to be eligible for Engineering and Physical Sciences Research Council (EPSRC) funding so need to be from the UK or EU. Full eligibility criteria can be found on the EPSRC site: www.epsrc.ac.uk/skills/students/help/eligibility 

Apply: This studentship is open now and will be available until it is filled. To apply please visit the University Of Nottingham application page: www.nottingham.ac.uk/pgstudy/apply/apply-online.aspx 

Please quote ref: SCI/1449