- Analysis Sime The Equations Of State Are Explicit In Pressure And Temperature Is Fixed It Is Convenient To Use Egs 1 1 (136.07 KiB) Viewed 12 times
ANALYSIS: Sime the equations of state are explicit in pressure, and temperature is fixed, it is convenient to use Egs. 11.50 and 11.51, which reduce to read. V₂₁₂ (1) u(va, T) -u (v₁, T) = √ [T), -p] dv 5(v₂, T) - S(V₁,7)= (** (2), dv (2) Alsu, Ah can be found using Eq. 11.61: h₂-h₁ = (U₂-4₁) + (P₂ V₂-P₁ Vz) (8) (a) van der Waals. This equation is explicit in pressure. So (OP/2T), = R/Cv-b). Eq. (1) then becomes ½ V₁₂ 12₂2 u(v₁, 1) - u(v₁, 7) = ((-p) dv: (E-P). [ - ( # - $ ) ) *** ( * adv su Thus 4h h(v₂, 7) h(y₁, T) = P(₁,7) 1/₂ - P(x₁,7) v₁ - (₂-1₁) Also, Eq. (2) becomes %₂ S(V₁, T) - (x₁, T) = √(√)]dv = R lu (VI-6)) 4 V-b V₁ (6) Redlich-kwong. This equation is explicit in pressure. So, p/ar) = 2 V (V+)71/2. Eq.(1) then becomes Å a + A ults, T) - (1,7) V-6 * 27%) - (1 - 6172)) r dv 2 267"L (+6) 7 1/2 h(vo, 7)-h (V₁, T) = P(V₂, T) ₂ - P(V₁, TV₁ - du 20617712 t [1 Also, Eq. (2) becomes .... + $(₂,7)- $(₁,7)= Thus = 7 v-b 2v(V+6) [%] + V₂+6 %] . R ( 1 ) - [ ] ماه 45
Develop expressions for the specific enthalpy and entropy changes [h(v2, T) - h(v₁, T)], [s(v₂, T) - s(v₁, T)], using the Redlich-Kwong equation of state. Using these expressions, determine the changes in specific enthalpy, in kJ/kmol, and entropy, in kJ/kmol. K, for ethylene between 400 K, 1 bar and 400 K, 200 bar. As = i ! kJ/kmol. K Ah = i ! kJ/kmol