City Research Online

Abstract

Low specific speed compressors have been historically based on positive displacement machines. Attempts to bring advantages of turbomachinery such as oil free, low parts counts, low cost of manufacture, and reliability to low flow rate applications have not been sparse, but the principle difficulty has always been that the conventional turbomachine design operates at ultra-high speed to deliver low volume flow rates. This is synonymous with low efficiency due to higher losses (windage, surface finish, and tip clearances). The innovative TurboClaw® design is a low specific speed turbomachinery with forward swept impeller geometry. It owes its high efficiency and operational stability to careful design of its nearly tangential forward swept blading and diffuser geometry. The present contribution describes the design and development of a high speed test rig to accurately measure TurboClaw efficiency using shaft torque. The test rig employs a permanent magnet high speed motor designed and developed for this purpose. The motor shaft drives a single stage TurboClaw® compressor via a high speed torque sensor. The results are presented and compared to data obtained through an energy balance method well established for this geometry since its first innovative development at Imperial College in 2003. The accurate performance measurements have been used to design and test a two stage compressor to recover energy from waste steam. This is also briefly described.

Publication Type:	Article
Subjects:	T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Engineering

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