Design Validation of High Speed Ratio Epicyclic Gear Technology in Compression Systems

Epicyclic gear technology is a key factor to support the compression growth strategy in electrified applications, due to the ever increasing transmission ratio required to meet the high compressor speeds. The paper collects the experience of the authors in developing a unique product through its conceptual design, as well as its mechanical and rotordynamic assessment, up to its complete validation with a full speed full load test in a complete unit arrangement. The main target of high pressure ratio compressors is to fulfil the required compression service with one casing less than traditional technology. Shawn Buckley Engineering Director Allen Gears Pershore, UK Shawn Buckley is currently the Engineering Director at Allen Gears (part of GE Oil & Gas) based in Pershore, UK joining early 1990. Shawn is responsible for leading both the original equipment and services engineering design teams producing bespoke gearboxes for a wide range of applications from power generation to naval marine main propulsion drives, employing parallel shaft, epicyclic and compound epicyclic gearing solutions. He is engineering apprentice trained and studied through the open university and is currently a member of the API 677 Task Force. Paul Bradley Engineering Technical Director Allen Gears Pershore, UK Paul Bradley is Technical Director at Allen Gears and has over 20 years experience working within the power transmission and rotating equipment industry covering gearbox design, rotordynamic analysis, bearing design and gear manufacture. He has worked on applications covering power generation, oil and gas and marine, and in addition to transmission technology his work has involved research and testing in the fields of high speed hydrodynamic bearing performance and super critical rotordyanmic instability phenomenon. He holds a PhD in Mechanical Engineering from Cranfield University and is an active member of several British Gear Association (BGA), ISO and API committees. The new compressor technology results in machines which run much higher in speed. To achieve a compressor ratio of ~30 in a single casing, the rotational speed is increase by roughly 40% respect to a traditional compression train, and therefore it becomes the most critical parameter. The specific requirements of higher speeds at high powers dictate the need for the very high speed ratio gearing, which was critical to the success of the new compressor technology. The power transmission was jointly developed by the gear and compressor manufacturers. The methods used to evaluate the gearbox configuration options are detailed in this paper, along with the gearbox specific technology design challenges faced.