Work
The working fluid can be used to output useful work if used in a turbine. Also, in thermodynamic cycles energy may be input to the working fluid by means of a compressor. The mathematical formulation for this may be quite simple if we consider a cylinder in which a working fluid resides. A piston is used to input useful work to the fluid. From mechanics, the work done from state 1 to state 2 of the process is given by
Where ds is the incremental distance from one state to the next and F is the force applied. The negative sign is introduced since in this case a decrease in volume is being considered. The situation is shown in the figure which follows.
The force is given by the product of the pressure in the cylinder and its cross sectional area such that
Where A.ds = dV is the elemental change of cylinder volume. If from state 1 to 2 the volume increases then the working fluid actually does work on its surroundings and this is commonly denoted by a negative work. If the volume decreases the work is positive. By the definition given with the above integral the work done is represented by the area under a pressure - volume diagram. If we consider the case where we have a constant pressure process then the work is simply given by
Read more about this topic: Working Fluid
Famous quotes containing the word work:
“The dominant and most deep-dyed trait of the journalist is his timorousness. Where the novelist fearlessly plunges into the water of self-exposure, the journalist stands trembling on the shore in his beach robe.... The journalist confines himself to the clean, gentlemanly work of exposing the griefs and shames of others.”
—Janet Malcolm (b. 1934)
“... you can have a couple of seconds to rest in. I mean seconds. You have about two seconds to wait while the blanker is on the felt drawing the moisture out. You can stand and relax those two seconds—three seconds at most. You wish you didn’t have to work in a factory. When it’s all you know what to do, that’s what you do.”
—Grace Clements, U.S. factory worker. As quoted in Working, book 5, by Studs Terkel (1973)
“His work was that curious mixture of bad painting and good intentions that always entitles a man to be called a representative British artist.”
—Oscar Wilde (1854–1900)