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:
“Memory is a wonderfully useful tool, and without it judgement does its work with difficulty; it is entirely lacking in me.... Now, the more I distrust my memory, the more confused it becomes. It serves me better by chance encounter; I have to solicit it nonchalantly. For if I press it, it is stunned; and once it has begun to totter, the more I probe it, the more it gets mixed up and embarrassed. It serves me at its own time, not at mine.”
—Michel de Montaigne (1533–1592)
“The next work of Carlyle will be entitled “Bow-Wow,” and the title-page will have a motto from the opening chapter of the Koran: “There is no error in this Book.””
—Edgar Allan Poe (1809–1845)
“The complexion of the element
In favor’s like the work we have in hand,
Most bloody-fiery, and most terrible.”
—William Shakespeare (1564–1616)