Page 16 - Advanced Gas Turbine Cycles

PREFACE

Many people have described the genius of von Ohain in Germany and Whittle in the
United Kingdom, in their parallel inventions of gas turbine jet propulsion; each developed
an engine through to first flight. The best account of Whittle’s work is his Clayton lecture
of 1946 [l]; von Ohain described his work later in [2]. Their major invention was the
turbojet engine, rather than the gas turbine, which they both adopted for their new
propulsion engines.
Feilden and Hawthorne [3] describe Whittle’s early thinking in their excellent
biographical memoir on Whittle for the Royal Society.
“‘I‘he idea for the turbojet did not come to Whittle suddenly, but over a period
of some years: initially while he was a final year flight cadet at RAF Cranwell
about 1928; subsequently as a pilot officer in a fighter squadron; and then
finally while he was a pupil on a flying instructor’s course.. . . While involved
in these duties Whittle continued to think about his ideas for high-speed high
altitude flight. One scheme he considered was using a piston engine to drive a
blower to produce a jet. He included the possibility of burning extra fuel in the
jet pipe but finally had the idea of a gas turbine producing a propelling jet
instead of driving a propeller”.

But the idea of gas turbine itself can be traced back to a 1791 patent by Barber, who
wrote of the basic concept of a heat engine for power generation. Air and gas were to be
compressed and burned to produce combustion products; these were to be used to drive a
turbine producing a work output. The compressor could be driven independently (along
the lines of Whittle’s early thoughts) or by the turbine itself if it was producing enough
work.
Here lies the crux of the major problem in the early development of the gas turbine. The
compressor must be highly efficient-it must use the minimum power to compress the gas;
the turbine must also be highly efficient-it must deliver the maximum power if it is to
drive the compressor and have power over. With low compressor and turbine efficiency,
the plant can only just be self-sustaining-the turbine can drive the compressor but do no
more than that.
Stodola in his great book of 1925 [4] describes several gas turbines for power
generation, and Whittle spent much time studying this work carefully. Stodola tells how in
1904, two French engineers, Armengaud and Lemae, built one of the first gas turbines, but
it did little more than turn itself over. It appears they used some steam injection and the
small work output produced extra compressed air-but not much. The overall efficiency
has been estimated at 2-3% and the effective work output at 6- 10 kW.
Much later, after several years of development (see Eckardt and Rufli [5]),
Brown Boveri produced the first industrial gas turbine in 1939, with an electrical power

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