Page 18 - Advanced Gas Turbine Cycles

Preface xv

“When in jet engine design, greater accuracy was necessary for detail design, I worked
in pressure ratios, used y = 1.4 for compression and y = 1.3 for expansion and assumed
specific heats for combustion and expansion corresponding to the temperature range
concerned. I also allowed for the increase in mass flow in expansion due to fuel addition
(in the range 1.5-2%). The results, despite guesswork involved in many of the
assumptions, amply justified these methods to the point where I was once rash enough to
declare that jet engine design has become an exact science”. Whittle’s modifications of air
standard cycle analysis are developed further in the later parts of Chapter 3.
Hawthorne eventually wrote up his MIT notes for a paper with his research student,
Graham de Vahl Davis [ 161, but it is really Will Hawthorne who should have written this
book. So I dedicate it to him, one of several great engineering teachers, including Keenan,
Taylor and Shapiro, who graced the mechanical engineering department at MIT when I
was there as a young assistant professor.
My subsequent interest in gas turbines has come mainly from a happy consulting
arrangement with Rolls Royce, plc and the many excellent engineers I have worked with
there, including particularly Messrs.Wilde, Scrivener, Miller, Hill and Ruffles. The
Company remains at the forefront of gas turbine engineering.
I must express my appreciation to many colleagues in the Whittle Laboratory of the
Engineering Department at Cambridge University. In particular I am grateful to Professor
John Young who readily made available to me his computer code for “real gas” cycle
calculations; and to Professors Cumpsty and Denton for their kindness in extending to me
the hospitality of the Whittle Laboratory after I retired as Vice-Chancellor of the Open
University. It is a stimulating academic environment.
I am also indebted to many friends who have read chapters in this book including John
Young, Roger Wilcock, Eric Curtis, Alex White (all of the Cambridge Engineeering
Department), Abhijit Guha (of Bristol University), Pericles Pilidis (of Cranfield
University) and Giampaolo Manfrida (of Florence University). They have made many
suggestions and pointed out several errors, but the responsibility for any remaining
mistakes must be mine.
Mrs Lorraine Baker has helped me greatly with accurate typing of several of the
chapters, and my friend John Stafford, of Compu-Doc (silsoe-solutions) has provided
invaluable help in keeping my computer operational and giving me many tips on preparing
the material. My publishing editor, Keith Lambert has been both helpful and encouraging.
Finally I must thank my wife Sheila, for putting up with my enforced isolation once
again to write yet another book.

J. H. Horlock
Cambridge, June 2002

REFERENCES

[l] Whittle, Sir Frank. (1945). The early history of the Whittle jet propulsion engine, Proc. Inst. Mech. Engrs.
152,419-435.
[2] von Ohain, H. (1979), The Evolution and Future of Aero-propulsion Systems. 40 Years of Jet Engine
Rogress. W.J. Boyne, and D.S. Lopez, (ed.), National Air and Space Museum, Washington DC.