14th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
Active and passive flow control
In order to separate the oil-lubricated bearing side of a turbomachine from the operating medium using a gas, sealants are subject to very high requirements. Aerostatic seals are considered to be very robust sealing systems and frequently used in the industrial applications. Anyhow, the performance and versatility are currently limited due to the geometrical restrictions in conventional manufacturing routes. In this context, additive manufacturing methods offer great potential to optimize functionality as well as adaptability to each particular field of application. The main advantage of these production methods is that the necessary permeability can be designed through structured and defined porosityas required. For instance, the characteristics and direction of the permeability can be controlled to affect the gas flow. However, the exploitation of this potential requires numerical models that can assist the design defined structured of additively manufactured dry gas seals. In this work, the process known as Laser Powder Bed Fusion of Metals is used to build up coaxial gas seals with defined permeability distributions. In order to investigate the seal performance, a test bench is designed, manufactured, and put into operation to validate numerical calculations performed in advance. The main parameters of the aerostatic gas-lubricated seals which are analyzed are the micrometer size gap, the gas flow through the seal, and the inlet pressure. In this work it is shown that a fabrication of additive manufactured dry gas seals with the needed characteristics is possible and the validated numerical model can be used for the future engineering of an aerostatic dry gas seals.