Lecture 9 Flashcards
What are the three sources of entropy in a system with formula?
Entropy due to heat flow: dQ/T
Entropy due to irreversible process: dS_irr
Entropy change due to mass flow: m_in/out s
What are the equations for entropy change due to irreversible processes
ds_irr = dw_r/T
ds_irr = (du + p dv)/T
ds_irr = (dh - v dv)/T
What is total entropy change for diabatic systems?
ds = dq/T + dw_r/T = ds_q + ds_irr + mass flow s
What is entropy change for closed, adiabatic, reversible process?
0
What is the value of dS_sys/dt for steady system?
0
When can entropy change of a single system be smaller than 0
When the entropy change of the entire system is greater than 0
What is the 2nd Law of thermodynamics?
Entropy only increases or remains constant
Do work and internal energy change or transport entropy?
No
Can common case equation be used if the case deviates slightly?
No. Go back to entropy balance.
What is the common case entropy equation with v_2/v_1 good for?
Closed system
What is the common case equation with p_2/p_1 useful for?
Open system
What is a simplification that can be made to common case entropy equation for incompressible fluids and solid bodies?
p dv / T = 0
What is heat transfer for reservoirs?
0
Is it possible to generate work from a single heat reservoir?
No
What do equilibrium states of isolated systems exhibit?
Maximum Entropy
