2013-3-6 Entropy and Heat Transfer By inspection of Eq.6.2a,the defining equation for entropy change on a differential basis is s-(9 (Eq.6.2b) Equation 6.2b indicates that when a closed system undergoing an internally reversible process receives energyby heat increase in entropy.Conversely,when energy is removed by heat transfer,the entropy of the system decreases. From these considerations,we say that entropy transfer accompanies heat transfer.The direction of the entropy Entropy and Heat Transfer In an internally reversible.adiabatic process (no heat transfer),entropy remains constant.Such a constant entropy process is called an isentropic process. On rearrangement,Eq.6.2b gives (80)m=Tds Integrating from state 1 to state 2, 0n-Tds (E4.6.23) 72013-3-6 7 Entropy and Heat Transfer ►By inspection of Eq. 6.2a, the defining equation for entropy change on a differential basis is (Eq. 6.2b) ►Equation 6.2b indicates that when a closed system undergoing an internally reversible process receives energy by heat transfer, the system experiences an increase in entropy. Conversely, when energy is removed by heat transfer, the entropy of the system decreases. From these considerations, we say that entropy transfer accompanies heat transfer. The direction of the entropy transfer is the same as the heat transfer. Entropy and Heat Transfer Integrating from state 1 to state 2, (Eq. 6.23) ►On rearrangement, Eq. 6.2b gives ►In an internally reversible, adiabatic process (no heat transfer), entropy remains constant. Such a constant￾entropy process is called an isentropic process