Design and Shape Optimisation of Nozzles for a Flat Air Bearing Device

This study offers a numerical and experimental study in the design and further shape optimisation of nozzles for a flat type air-bearing device which is supposed to be used for handling a certain magnitude of loads. Making use of pressurised air allows for the design of mechanical systems requiring handling heavy loads or extreme precision in positioning. In a design of flat type air-bearings, particularly when carrying heavy loads is considered, the shape of nozzles becomes very important. In order to analyse and further optimisation of the dimensions of a nozzle in this study, Computational Fluid Dynamic (CFD) analysis with k-ω turbulence modelling has been performed to simulate the supersonic fluid flow behaviour inside the chamber and divergent nozzle of the bearing device. Three different geometries with fixed inlet diameter of 2 mm and outlet diameters of 3, 6 and 12 mm were studied. An experimental investigation was conducted with the same nozzle geometries and also different nozzle numbers (and arrangements) to find the best option with respect to the performance in handling loads. Results from experimental study are in accordance with results of CFD analysis, making the numerical modeling a useful tool for a comparative study in this research to determine the optimum size and shape of nozzles as well as optimum pressure for a particular load.