Thermodynamics — MEEN 315

Evaluating Specific Entropy

Compressed Liquid, $s(p, T)=s_f(T)$

Saturated Mixture, $s(p,T)=(1-x)s_f+(x)s_g$

Superheated Vapor, $s(p,T)$

Closed System Processes

Entropy Change, Exchange, and Production

$$ m(s_2-s_1)=\int_1^2(\frac{\delta Q}{T})_b+\sigma $$

Instantaneous Rates of Entropy Change, Exchange, and Production

$$ m\frac{ds}{dt}=\Sigma\frac{\dot{Q}}{T}+\dot{\sigma} $$

Control Volumes

Entropy Rate Balance

$$ \dot{m}_{_T}\frac{ds}{dt}=\Sigma\frac{\dot{Q}}{T}+\Sigma\dot ms+\dot\sigma $$

Ideal Gas States and Processes

$$ pv=RT $$

Change in Specific Internal Energy and Enthalpy

$$ u_2-u_1=\int_{T_1}^{T_2}c_v(T)dT $$

Constant Specific Heats

$$ h_2-h_1=\int_{T_1}^{T_2}c_p(T)dT $$

$$ c_v=const\Rarr\Delta u=c_v\Delta T $$

$$ c_p=const\Rarr\Delta h=c_p\Delta T $$

Variable Specific Heats