Engineering Equation Solver Ees Cengel Thermo Iso Apr 2026

"Isothermal boundary work for ideal gas" W_b = m R T ln(v2/v1) "Negative if compressed" "Alternatively:" W_b = m R T ln(P1/P2)

| Cengel Table | EES function | |--------------|---------------| | Saturated water T | v_f = volume(Water, T=T_sat, x=0) | | Saturated water P | h_g = enthalpy(Water, P=P_sat, x=1) | | Superheated | v = volume(R134a, T=T, P=P) | | Compressed liquid approx | h(T,P) ≈ h_f@T in EES: h = enthalpy(Fluid$, T=T, P=P) (EES corrects) |

P1 = 3 [MPa] T1 = 400 [C] P2 = 50 [kPa] Fluid$ = 'Steam' s1 = entropy(Fluid$, P=P1, T=T1) h1 = enthalpy(Fluid$, P=P1, T=T1) Engineering Equation Solver EES Cengel Thermo Iso

EES is case-insensitive but uses ^ for power. 3. Implementing Iso-Processes in EES a) Isobaric (( P = constant )) Cengel rule: ( P_1 = P_2 ), ( Q - W_b = \Delta H ) (for closed system, often ( W_b = P\Delta V )).

"1st law for ideal gas isothermal: Δu=0" Q_in = W_b Most powerful in EES – just set ( s_2 = s_1 ) and EES finds the rest. "Isothermal boundary work for ideal gas" W_b =

"Given final state: superheat to T2" T2 = 80 [C] v2 = volume(Fluid$, P=P2, T=T2) u2 = intEnergy(Fluid$, P=P2, T=T2) h2 = enthalpy(Fluid$, P=P2, T=T2)

"Actual (given efficiency η=0.85)" η = 0.85 η = (h1 - h2a)/(h1 - h2s) h2a = h1 - η*(h1 - h2s) W_a = h1 - h2a EES replaces table lookup: "1st law for ideal gas isothermal: Δu=0" Q_in

R = 0.287 [kJ/kg-K] "Air" T = 300 [K] m = 1 [kg] P1 = 100 [kPa] P2 = 500 [kPa] v1 = R T/P1 v2 = R T/P2

"1st law" Q_in - W_b = m*(u2 - u1) Rule: ( v_1 = v_2 ), ( W_b = 0 ), ( Q = \Delta U ).

"Given" P1 = 100 [kPa] T1 = 300 [K] P2 = 1000 [kPa] Fluid$ = 'Air' "EES treats as ideal gas with var cp" s1 = entropy(Fluid$, P=P1, T=T1) "Isentropic" s2 = s1 T2 = temperature(Fluid$, P=P2, s=s2) h1 = enthalpy(Fluid$, T=T1) h2 = enthalpy(Fluid$, T=T2)

v2 = v1 "Final pressure given" P2 = 500 [kPa] T2 = temperature(Fluid$, P=P2, v=v2) u2 = intEnergy(Fluid$, P=P2, v=v2)