Modelling of melt on spinning wheels

Abstract

Thermal Ceramics manufacture high-temperature thermal insulation, much of which is made in the form of fibre, for use in furnaces, aeroengines, domestic appliances, fire protection systems and other applications. In the manufacturing process, a melt stream emerges from a circular orifice and falls on to two successive spinning wheels, resulting in fiberisation. However, the process also results in a significant fraction of unfiberised material in the form of shot particles. The presence of shot tends to increase the thermal conductivity of the final product. Moreover, some areas of application, such as the automotive industry, require clean fibre with zero shot. Reducing the amount of shot that is produced in the fiberisation process would also reduce the costs of 'cleaning' the fibres for these markets. The Study Group was asked to look at how melt transfers on to the spinning wheels, what kind of melt layer exists on the wheels, and how this layer breaks up. By using a mathematical model to understand the relative importance of various parameters, it is hoped to guide experimental trials and then the scale-up to production levels.