An investigation of the heat transfer by conduction and radiation between hot glass and tool moulding

Gheblawi, Ezzeddin (2006) An investigation of the heat transfer by conduction and radiation between hot glass and tool moulding. Doctoral thesis, Northumbria University.

Preview

PDF (PhD thesis) ezzeddin.gheblawi_phd.pdf - Accepted Version Download (18MB) | Preview

Abstract

This research work investigates heat transfer through the contact line between a glass mould and plunger in a press forming process. Models are formed and compared with experimental measurements to enable clarification of the glass properties that should be used in the optimisation process and have been suggested in previous research works. Two cases of heat transfer are considered in the models firstly the case of both conductive and radiative are present and then the case of radiative (reheat). The models developed during the study are based on one-dimensional heat transfer. The model is based on the period of the formation process starting from the point at which the molten glass is brought into contact with a mould until the time at which the formed glass is inverted. The models are concerned with the changes in temperature profile during this period at both the centre and the surface of the glass depending on the mode of heat transfer considered, the properties of the glass, and the properties of the tooling. The properties of the glass considered in the models include the absorption coefficient, refractive index, heat transfer coefficient, internal and external emissivity, specific heat and conductivity. In the radiation case the modelling results show the internal emissivity has a little effect on the surface temperature while the external emissivity has an effect temperature fall. Modelling of changes in glass thickness and glass absorption coefficient during the reheat stage of the process has been carried out based on white and green glass. Validation of these models has been accomplished by performing experimental work.

Actions (login required)

View Item

Downloads