Willem Potze

Radiation heat transfer in axisymmetric quartz glass tubes

A mathematical model is proposed to describe the heat transfer in quartz glass axisymmetric tubes. Heat is transferred inside the glass by radiation and conduction. Scattering of thermal radiation inside the glass is ignored. At the boundaries of the tube the radiative intensity is specularly reflected. The spectral dependent radiative intensity and the temperature distribution inside the tube are determined. The model is applied to simulate the cooling process of a quartz glass tube. The calculated temperature is in agreement with that obtained from an experiment. Furthermore, steady-state temperature distributions in quartz glass tubes of different lengths have been determined.

Transmission deflectometer for high-range lens slope measurement

A new lens slope measurement system is developed and realized in the Philips CFT laboratory, which is named a transmission deflectometer. The slopes of two lenses are measured with this measurement system. A high measurement accuracy, 0.05 mrad, over a wide measurement range of ± 17° could be reached.