The Physics
An encyclopedia of scientific essays

Temperature of Steam in a Turbine

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Bibliographic Entry Result
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Cutnell, Johnson. Physics: Fourth Edition. Canada: Wiley, 1998: 454. "A power plant taps steam superheated by geothermal energy to 505K …." 232 °C
"Steam Turbine." McGraw-Hill Encyclopedia of Science and Technology. New York: McGraw Hill, 1973. "Units of this general type provide 10-1000 hp (7.5-750 kW) with steam at 100-600 lb/in.2 gage (0.7-4.1 megapascals) inlet pressure and temperatures to 800°F (427°C)." 427 °C
Three Alsthom Steam Turbine Generators 17Mw 50Hz. Warp Machinery Exchange. "Make Alsthom Model T167-215 Inlet Pressure 40 bar Inlet Temperature 465°C …." 465 °C
H. W. Dickinson. A Short History of the Steam Engine. London: F. Cass, 1963: 216. "This historic turbine developed the power stated at 500 r.p.m. with dry saturated steam of 150 lb. per sq. in. pressure, temperature 380°F …." 190 °C
400 MW GE Model G2 Steam. The Utility Warehouse. "Boiler - Keller Type CP - S/N 15505, built 1973, Operating Pressure 450F, operated at 400F. Super heat 600F operated at 535F" 200-315 °C

Do you ever wonder where power plants and submarines get their power from? Ever watch a movie, and ponder what those conical things are in factories? Both of these questions share a common guideline, the steam turbine.

A steam turbine converts energy from internal energy, in the form of heat, into mechanical energy, that is, energy that can be transformed. The laws of thermodynamics state that when a vapor expands, its temperature drops, and its internal energy is consequentially decreased. The action of the steam turbine is based on this principle. The transformation makes a large amount of work energy available for use.

A steam turbine consists of stationary and rotating blades on an axle. High pressure steam enters the turbine. The steam can be anywhere from 200 °C to 400 °C. The stationary blades direct streams of high pressure steam onto the rotating blades, which turns the axle. The steam then travels through two or more consecutive stages of stationary and rotating blades. Multiple stage are highly efficient.

Due to the increase in volume as the steam expands through the various stages of a turbine, the size of the openings that the steam passes through must increase from stage to stage. The blades are lengthened from stage to stage to allow the expansion of steam. As a result, a small industrial turbine may be more or less conical in shape, with its smallest diameter at the high-pressure end and its largest at the low-pressure end. This would explain the conical shape seen on TV.

Alan Furmanov -- 2003