In 1941, Sir Frank Whittle designed the first successful turbojet engine for air defense during World War II. Dubbed the Gloster Meteor, it flew in defense over Great Britain. Whittle improved his jet engine as the war progressed. He shipped a prototype engine to General Electric in the United States in 1942. GE built America’s first jet engine for military aviation applications the following year.
Whittle came to the USA for the first time on a secret mission in the summer of 1942. He met with officials from General Electric in Lynn, MA and Bell Aircraft Company in Buffalo, NY. Later in 1942, he visited GE in Schenectady, NY, where a rudimentary propeller jet engine was under development. Whittle’s comments and suggestions to American engineers proved invaluable in modifications and improvements that soon followed.
One can argue that the development of jet engine might have been accelerated had World War II lasted longer. However, the other side of that argument is that the application of turbo-technology to other industries became a post-war quest of American industry. In the eyes of many engineers on both sides of “the pond,” this method of power production and propulsion could be used to drive land-based generators, compressors and other load devices, as well as to propel ships and aircraft in commercial applications. All that was needed was funding and the imagination of the engineers involved, eager as they were to apply this innovative prime mover.
Fig. 1-1: Sir Frank Whittle and his multi-combustor jet turbine (circa 1941)
The multi-combustor, turbo-jet engine (hereafter called the gas turbine) has Frank Whittle proudly standing beside it in Fig. 1-1. Notice that there are 10 combustion chambers (tube shaped) encircling the engine, with stainless steel nozzles to inject fuel into them at the front ends. The chambers are interconnected by cross-fire tubes, as is common on most modern gas turbines. The exhaust diffuser is in the center. The reverse-flow concept of the hot gases is obvious from the photograph. So are the transition pieces curling from the discharge of each combustor.
“If necessity is the mother of invention,” as preached to engineering students by college professors, then the end of WW-II brought many needs to the front burner ready to be invented. Jet engine technology needed to be harnessed and applied to other commercial endeavors. As a prime mover, the gas turbine needed to find applications that could deliver power to other modes of transportation, electrical power delivery and natural gas pipelines prime movers. However, as inventors soon found, not every idea has a viable application to industry, or a willingness of the public to accept them. Engineers like Whittle would encounter doubters, the enemies of progressive thinkers. Progress often depended upon inventors who could convince entrepreneurs and angel investors to take a chance on their ideas and innovations. This presumes that negative forces are not overwhelmingly against such visionaries. As explained in later chapters of this blog, GE engineers struggled to get funding in a fledgling gas turbine department in Schenectady, NY in the 1950s.
It is uncertain if Frank Whittle could have envisioned a modern gas turbine like the one shown in Fig. 1-2 below. A single-fuel (natural gas) General Electric MS7001EA gas turbine (approximately 80 megawatt rating) is shown, with fuel line “pigtails” coming from the manifold on the left leading to each combustor. The chambers themselves are inside the combustion wrapper, which encircles the turbine, so only the covers are showing.
Since the combustors are interconnected via cross-fire tubes, only one combustor needs to have a sparkplug (igniter) and another, a flame detector. However, for redundancy and reliability, modern gas turbines typically have at least two of each, as shown in Fig. 1-3.
Design of combustion systems, like those depicted herein, seems to be a “settled” issue. Most manufacturers have decided that this is the design that makes the most sense. It allows for temperature equalization and flow distribution to the first-stage turbine nozzle and rotating wheels with buckets (blades) that develop the output power. Refer to Fig. 1-4 below.
Fig. 1-5 below should be studied for its completeness regarding the design of a typical modern combustion system for a GE MS7001EA gas turbine. Notice that the combustors are “canted” in design to straighten the hot gas flow through the transition pieces toward the first-stage nozzle (not shown). Also, this design shortens the length of the turbine and thus bearing spans. The reverse flow of the air from the compressor discharge casing is also shown entering the combustor.
Other areas of development have also occurred over the past 70 years with gas turbine technology. Advances in metallurgy, ceramic coatings and internal cooling designs have evolved over the past seven decades, to a point where efficiencies and higher internal firing temperatures have made the gas turbine a viable competitor to other forms of power generation.
In conclusion, over sixty years ago an engineer from Britain named Frank Whittle envisioned, designed and built a multi-combustor, aero-derivative gas turbine engine for land-based applications. His innovative design in gas turbine technology has prevailed for the following six decades well into the 21st century.
Taken from Lucier Blog
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