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:
“But this rough magic
I here abjure, and when I have required
Some heavenly music—which even now I do—
To work mine end upon their senses that
This airy charm is for, I’ll break my staff,
Bury it certain fathoms in the earth,
And deeper than did ever plummet sound
I’ll drown my book.”
—William Shakespeare (1564–1616)
“When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; what is man, that thou art mindful of him? and the son of man, that thou visitest him? For thou hast made him a little lower than the angels, and hast crowned him with glory and honour.”
—Bible: Hebrew Psalms, 8:2.
“Man was kreated a little lower than the angells and has bin gittin a little lower ever sinse.” (Josh Billings, His Sayings, ch. 28, 1865)
“It is ultimately in employers’ best interests to have their employees’ families functioning smoothly. In the long run, children who misbehave because they are inadequately supervised or marital partners who disapprove of their spouse’s work situation are productivity problems. Just as work affects parents and children, parents and children affect the workplace by influencing the employed parents’ morale, absenteeism, and productivity.”
—Ann C. Crouter (20th century)