Mathematical Model of an Autoclave

This paper presents the mathematical modelling of the following autoclave processes: heating, cooling and pressure changes.An autoclave is a pressure vessel of a cylindrical form where the composite semi-products are placed on a metal plate above electrical heaters and heated at selected temperatures and under a higher pressure.The purpose of the modelling is to build a mathematical model with which the behaviour of the processes can be simulated and the temperature and pressure control in the autoclave can be improved.Furthermore, using this mathematical model we intend to test advanced uni-and multi-variable control algorithms.The mathematical model is built on the basis of the heat-transfer and pressure-changing theories.While the pressure-changing process is not very complex, the heating and cooling processes involve complex phenomena of heat conduction and convection.In the mathematical model some simplifications were considered and so the heat-transfer correlations past flat plates were used.Most of the data are real and obtained from the autoclave manufacturer, but where not possible, the method of the model's response fitting to the measured data with the criterion function of the sum of squared errors was used.In this way, to a great extent simulated similarly to the real process responses were obtained.It can be concluded that the obtained mathematical model is usable for the design of a variety of process-control applications.