Next generation aeroderivative-I

May 1 2013 - Ivan G Rice

History tells us that industrial gas turbines, both aero and HD units, are technically closely linked to the jet and fan engines used for fighter planes and large military transports. The cold war with Russia spurred our government and that of England to spend huge amounts of money in the development of these engines. Great progress was made over the years.

After the Korean, Vietnam and Russian cold war, federal funding dropped off somewhat, but even so, progress continued at a rapid pace. Because of the large capital needed and the risks involved in developing commercial engines, companies turned to forming groups of companies to share in the risks, manufacturing of parts, capital expenditures and profits. Not all projects turned out to be winners. One of the first successful joint ventures was the union of GE and the French company Snecma for the development of the TF - 56 fan engine for the Boeing 737.  Today, there are many such conglomerate organizations formed to fund and make fan engines for the airline industry.

Over the past 25 years, unbelievable progress has been made to give the world the modern day fan engines and the HD GTCCs with over 60 percent cycle efficiency. New fan engines and advanced GTCCs are now entering service. The cycle efficiency of GTCCs is projected by the author to reach 65 percent in a few years.

Background of gas turbine development

Let us briefly look back to 1937 when Brown Boveri first introduced a large and bulky axial flow 3500 KW gas turbine generator set. The machine was very large for its output, the size of a bloated box car and having a huge combustor on the top. Engineers from various countries around the world went to Switzerland to see the monster run. Most were skeptical of the potential of the machine with only 17 percent efficiency. The gas turbine fired at about 1200o F and had a pressure ratio of about 4, but it did run and produce AC power. It was an improvement over the earlier constant-volume even larger Holzworth machine also built by Brown Boveri.

As an example of skepticism, the US Navy in 1940 issued a report stating that the GT was not suitable to propel ships and certainly could not be used to power airplanes. Nevertheless, there were two engineers who saw something different in the Brown Boveri Monster. Dr. Hans von Oham of Germany was first to shrink the size of the Swiss machine by applying a high speed axial flow compressor, an inline combustor system and an axial flow turbine.

The engine was developed in complete secrecy and powered a plane a year before the Sir Frank Whittle’s double flow radial compressor, cocked combustor cans and axial flow turbine first ran. The first time the West knew about this jet was when the ETO fighter pilots flying the fast Mustang P51s saw the twin M-262 without a propellers steak past them to their utter astonishment. The jets came too late to effect the outcome of the war but the effect on the commercial airline industry and the way of travel has been tremendous.

Since Pratt & Whitney introduced the geared turbofan aircraft engine, the question has been what is the next generation aeroderivative? Ivan Rice explores that question in this series.


Next generation aeroderivative-II

Next generation aeroderivative-III

Next generation aeroderivative-IV