2.2 Entropy not Conserved S.J.T.0. Phase Transformation and Applications Entropy is not conserved in natural processes,in contrast to the energy function(U) Steady state and no extraneous heat losses. Q,=-9m Energy is conserved. △U+w=△U,+AUm=2,+9u=0 The process of heat transfer at the boundaries of reservoirs I and II is considered to be reversible. ASin=AS,+ASy T-Tn ≠0 The irreversibility TTTT TTo gave rise to an entropy increase. SJTU Thermodynamics of Materials Fall 2012 X.J.Jin Lecture 4 Second law llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2012 © X. J. Jin Lecture 4 Second law II 2.2 Entropy not Conserved Entropy is not conserved in natural processes, in contrast to the energy function (U). TI TII Steady state and no extraneous heat losses. QI = −QII Energy is conserved. Δ = Δ + Δ = + = 0 UI +II UI UII QI QII The process of heat transfer at the boundaries of reservoirs I and II is considered to be reversible. ≠ 0 ⎥⎦⎤ ⎢⎣⎡ − + = − Δ + = Δ + Δ = + = I II I II II IIII I II IIII II I II I II T T T T Q TQ TQ TQ TQ S S S The irreversibility gave rise to an entropy increase