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A steam turbine or steam turbine engine is a machine or heat engine that ... Schematic diagram outlining the difference between an impulse and a 50% reaction turbine.
The degree of reaction contributes to the stage efficiency and thus used as a design parameter. Stages having 50% degree of reaction are used where the pressure drop is equally shared by the stator and the rotor for a turbine. Figure 4. Velocity triangle for Degree of Reaction = 1/2 in a turbine
Practical hydroelectric water turbines and steam turbines did not appear until the 1880s. Gas turbines appeared in the 1930s. The first impulse type turbine was created by Carl Gustaf de Laval in 1883. This was closely followed by the first practical reaction type turbine in 1884, built by Charles Parsons.
Fig-3: Schematic Diagram of Pressure compounded Impulse Turbine. The pressure compounded Impulse turbine is also called a Rateau turbine, after its inventor. This is used to solve the problem of high blade velocity in the single-stage impulse turbine. It consists of alternate rings of nozzles and turbine blades.
A steam turbine with the case opened Humming of a small pneumatic turbine used in a German 1940s-vintage safety lamp. A turbine (/ ˈ t ɜːr b aɪ n / or / ˈ t ɜːr b ɪ n /) (from the Greek τύρβη, tyrbē, or Latin turbo, meaning vortex) [1] [2] is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work.
A reaction engine is an engine or motor that produces thrust by expelling reaction mass (reaction propulsion), [1] in accordance with Newton's third law of motion.This law of motion is commonly paraphrased as: "For every action force there is an equal, but opposite, reaction force."
Efficiencies of the turbine stages can also be plotted against this ratio. Such plots for some impulse and reaction stages are shown in the figure. The performance of steam turbines is often presented in this form. The curves in Figure also show the optimum values of the velocity ratio and the range of off-design for various types of stages.
In 1882 he introduced his concept of an impulse steam turbine [2] and in 1887 built a small steam turbine to demonstrate that such devices could be constructed on that scale. In 1890, Laval developed a nozzle to increase the steam jet to supersonic speed, working from the kinetic energy of the steam, rather than its pressure.