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:
“You live on hopes, I guess. You always dream that someday you might have a lot of money, your ship might come in. But if the ship doesn’t come in, I’m going to work as long as I can.”
—Marion Gray (b. c. 1914)
“I must work, so as not to be a fool, to get on, to become a journalist, because that’s what I want!... I can’t imagine that I would have to lead the same sort of life as Mummy ... and all the women who do their work and are then forgotten. I must have something besides a husband and children, something that I can devote myself to!”
—Anne Frank (1929–1945)
“I see no reason for calling my work poetry except that there is no other category in which to put it.”
—Marianne Moore (1887–1972)