Diaphragm Stirling Engines: The Harwell Thermo-Mechanical Generator

Abstract

In free-piston Stirling engines, some of the more difficult design problems are concerned with wear and friction in the moving parts. Liquid lubricants cannot be used where they are exposed to the working gas, because they find their way into the hotter regions, where they decompose and clog the gas passages with solid matter. One approach is to use materials for the surfaces of piston and cylinder which will operate unlubricated with minimum wear. It has yet to be shown that this approach can lead to an engine operating life of more than a few thousand hours. Another approach is to use gas lubrication: some of the working gas being fed under pressure into the narrow space between piston and cylinder so as to keep the surfaces out of contact. This is said to be effective, but adds complication.

E.H. Cooke-Yarborough studied Physios at Oxford University from 1937 to 1940 and then joined the Air Ministry Research Establishment (later re-named the Tel ecommunications Research Establishment), where he worked on airborne radar3 on radar countermeasures and on guided weapons. He joined the Atomic Energy Research Establishment at Harwell in 1948, receiving Individual Merit promotion to Deputy Chief Scientist in 1955y and being appointed Head of the Electronics Division in 1957. In 1980 he was elected to the Fellowship of Engineering (whose membership consists of the 500 most prominent UK engineers) and was appointed Chief Research Scientist Instrumentation and Applied Physics Division. He left Harwell to become a private Consultant in 1982.

He led the teams which designed and put into operation at Harwell the second digital computer to go into regular use in the UK and, later, what was the first all-transistor digital computer in the UK, and the second in the world. He also led the team which developed and put into service the Thermo-mechanical Generator. He has been jointly awarded four Premiums by the Institution of Electrical Engineers: - two for innovations in Nuclear Instrumentation, one for a paper on Opto-electronic Computer Logic, and one for the invention of the Stirling-cycle Thermo-mechanical Generator. He is the author of the book ‘An Introduction to Transistor Circuits’ and of many papers on Nuclear Instrumentation, Electronic Circuits and Energy Conversion. About 75 UK patents have been filed in his name

G. Walker