EXPERIMENTAL STUDY ON PRESSURE LOSSES IN ADDITIVELY MANUFACTURED AND MACHINED ORIFICES : A rectangular geometry of additively manufactured MA 247 orice and a circular geometry ofmachined AW-6082 T6 orifice study

• Main Author: Nambisan, Jayadev
• Format: Others
• Language: English
• Published: Linköpings universitet, Mekanisk värmeteori och strömningslära 2020
• Subjects: Cooling; Fluid Dynamics; Additive Manufacturing; Pressure Losses; Fluid Dynamics Testing; Machining; Gas Turbines; Gas Turbine Cooling; Nouveau Geometries; Engineering and Technology; Teknik och teknologier
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-170131

Gas turbine components for cooling purposes including other unique and complex three-dimensional designs could be made explicitly possible through additive manufacturing using SLM technology in contrary to the conventional machining processes. Nevertheless, the surface roughness and subsequently the friction factor governs thepressure drop in these components implicitly, thus, influencing the secondary air flow system of a gas turbine. Research studies to understand and predict flow behaviours through especially AM parts are still in a budding stage, and thus, in this scope of thesis, the same has been attempted through experimentation to quantifypressure losses in additively manufactured rectangular orices. With the purpose of a brief analogy, a set of aluminium circular samples were also tested which were manufactured by the conventional process of machining. A total of 9 rectangular MA247 samples of different lengths and hydraulic diameters were tested as continuation to the ongoing research at Siemens Industrial Turbomachinery AB and further on to that, 5 Aluminium Alloy- AW-6082 T6 material samples of circular geometry with varying lengths were tested. The on-going research focuses on the additively manufactured geometries for both rectangular and circular, and hence, the data for circular orifices were used to draw a comparison with its Aluminium counterpart. Pressure losses here were described using the coefficient of discharge and the investigations on roughness were by calculating Darcy frictional factor and Colebrooks equation. Classical theories such as the boundary layer theory, Hagen's power law, Ward-Smith's theory for vena contracta and other works by previous researchers were used to validate the results. The coefficient of discharge could be deployed to restrict and measure the mass flow in the secondary air systems, whereas the results from the calculated frictional factors could be held to simulate the flow distribution in cooling geometries. === <p>E-presentation via Zoom due to the pandemic.</p> === Part of the on-going research on pressure loss study for Gas Turbine cooling purposes by Siemens Energy