Experimental and numerical study on the thermal control strategy for a gas foil bearing enhanced with thermoelectric modules

Abstract

The authors report the method for temperature gradient control in gas foil bearings with the use of thermoelectric modules. The paper presents a prototype installation consisting of a gas foil bearing with integrated 36 thermoelectric modules, an electric spindle, measurement and control system. The results of a preliminary qualitative and quantitative assessment of the investigated temperature gradient control are shown, making use of the carried out numerical simulations. Steady state thermal analyses were performed for the defined control currents assigned to the Peltier modules. The metamodeling technique improved the search for a suboptimal choice on the control currents values in terms of temperature gradient control efficiency. Consideration of simultaneous forward and backward heat pumping directions for the selected thermoelectric modules improved temperature gradient reduction by additional 10%. Moreover, the paper is complemented with the results of an experimental test performed for a prototype installation of a gas foil bearing. A straightforward adaptive algorithm, dedicated to control thermal parameters of the bearing’s foil, was successfully tested. The control algorithm allowed for a significant temperature gradient reduction, however considerable oscillations in the temperature profile were observed. In order to eliminate these oscillations, a PID controller was implemented into the algorithm. Consequently, the magnitude of the temperature oscillations was reduced by 60%.