Isentropic Relation

• An isentropic process is a reversible-adiabatic process. For an adiabatic process =0, and for a reversible process, =0. From Eq. (38.26), for an isentropic process, . However, in Eq. (38.37), substitution of isentropic condition yields

or

or

(38.39)

Using , we have

(38.40)

Considering Eq. (38.38), in a similar way, yields

or

(38.41)

Using , we get

(38.42)

• Using we can write

(38.43)

• Combining Eq. (38.40) with Eq. (38.43), we find,

(38.44)

This is a key relation to be remembered throughout the chapter.