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
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Famous quotes containing the word work:
“... possibly there is no needful occupation which is wholly unbeautiful. The beauty of work depends upon the way we meet it—whether we arm ourselves each morning to attack it as an enemy that must be vanquished before night comes, or whether we open our eyes with the sunrise to welcome it as an approaching friend who will keep us delightful company all day, and who will make us feel, at evening, that the day was well worth its fatigues.”
—Lucy Larcom (1824–1893)
“The best thing about Sassy Seats is that grandmothers cannot figure out how they work and are in constant fear of the child’s falling. This often makes them forget to comment on other aspects of the child’s development, like why he is not yet talking or is still wearing diapers. Some grandmothers will spend an entire meal peering beneath the table and saying, “Is that thing steady?” rather than, “Have you had a doctor look at that left hand?””
—Anna Quindlen (20th century)
“... married women work and neglect their children because the duties of the homemaker become so depreciated that women feel compelled to take a job in order to hold the respect of the community. It is one thing if women work, as many of them must, to help support the family. It is quite another thing—it is destructive of woman’s freedom—if society forces her out of the home and into the labor market in order that she may respect herself and gain the respect of others.”
—Agnes E. Meyer (1887–1970)