Practical gas power cycles are complex. We simplify our analysis by making the following approximations which are known as air standard assumptions.
(a) The working fluid is an ideal gas.
(b) The specific heats (cp & cv) are constant.
(c) The cyclic process is reversible.
(d) There is no dissociation at the end of the heating process.
(e) Circulating mass of the working fluid is constant in the cycle.
(f) Addition of heat to the cycle is done by an external source.
(g) Rejection of heat by the cycle is done to an external sink.
(h) There is no change in K.E. & P.E.