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The actual vapor power cycle differs from the ideal Rankine cycle because of irreversibilities in the inherent components caused by fluid friction and heat loss to the surroundings; fluid friction causes pressure drops in the boiler, the condenser, and the piping between the components, and as a result the steam leaves the boiler at a lower ...
1765 (): James Watt invents the separate condenser, the key being to relocate the water jet, (which condenses the steam and creates the vacuum in the Newcomen engine) inside an additional cylindrical vessel of smaller size enclosed in a water bath; the still-warm condensate is then evacuated into a hot well by means of a suction pump allowing ...
The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants (including boilers etc.), such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary ...
Steam engines and turbines operate on the Rankine cycle which has a maximum Carnot efficiency of 63% for practical engines, with steam turbine power plants able to achieve efficiency in the mid 40% range. The efficiency of steam engines is primarily related to the steam temperature and pressure and the number of stages or expansions. [15]
The figure of the Rankine cycle at the right shows a turbine rather than a reciprocating piston engine between states 3 and 4, but either device acts as the expander stage in the cycle. Condenser: The device between states 4 and 1 is the condenser. It removes heat from the engine exhaust steam to condense it back into water.
After the steam is used, it is then dumped to the main condenser. From the condenser, it is then pumped to the deaerated feed tank. From this tank it then goes back to the steam drum to complete its cycle. The feedwater is never open to the atmosphere. This cycle is known as a closed system or Rankine cycle.
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The steam then goes back into an intermediate pressure section of the turbine and continues its expansion. Using reheat in a cycle increases the work output from the turbine and also the expansion reaches conclusion before the steam condenses, thereby minimizing the erosion of the blades in last rows.