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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]
These diagrams were used to determine the efficiency of steam engines, such as those found aboard Western Rivers steamboats. Reason This image is of high technical standards, sufficient scalable resolution, is an excellent illustration of the related concepts, has a free license, supplements two separate articles, is accurate, has valuable ...
Example of a Sankey diagram Sankey's original 1898 diagram showing energy efficiency of a steam engine. Sankey diagrams are a data visualisation technique or flow diagram that emphasizes flow/movement/change from one state to another or one time to another, [1] in which the width of the arrows is proportional to the flow rate of the depicted extensive property.
An indicator diagram is a chart used to measure the thermal, or cylinder, performance of reciprocating steam and internal combustion engines and compressors. [1] An indicator chart records the pressure in the cylinder versus the volume swept by the piston, throughout the two or four strokes of the piston which constitute the engine, or ...
High pressure steam enters, red, and exhausts, yellow. The uniflow type of steam engine uses steam that flows in one direction only in each half of the cylinder. Thermal efficiency is increased by having a temperature gradient along the cylinder. Steam always enters at the hot ends of the cylinder and exhausts through ports at the cooler centre.
Indicator diagram for steam locomotive [3] Specifically, the diagram records the pressure of steam versus the volume of steam in a cylinder, throughout a piston's cycle of motion in a steam engine. The diagram enables calculation of the work performed and thus can provide a measure of the power produced by the engine. [4]
Frictional resistance is offered during the flow of steam through nozzles on moving and stationary blades. In most turbines, the blade wheels rotate in a space full of steam. The viscous friction at the wheel surface causes admission losses as steam passes from nozzle to wheel. The effect of partial admission creates eddies in the blade channels.
The thermal efficiency of modern steam turbine plants with reheat cycles can reach 47%, and in combined cycle plants, in which a steam turbine is powered by exhaust heat from a gas turbine, it can approach 60%. [4] Brayton cycle: gas turbines and jet engines The Brayton cycle is the cycle used in gas turbines and jet engines. It consists of a ...