Flash drum simulation

1 inlet -> vapor + liquid

Governing equations

The exact equations the solver works for a flash drum — the same math shown in the app's "Theory" panel, not a black box.

K_i = \frac{y_i}{x_i} = \gamma_i\,\frac{P_i^{sat}(T)}{P}

\sum_i \frac{z_i\,(K_i-1)}{1+\psi\,(K_i-1)} = 0 \quad(\text{Rachford-Rice})

x_i = \frac{z_i}{1+\psi(K_i-1)},\qquad y_i = K_i x_i

K: equilibrium ratio K=y/x — how strongly a component favours the vapour; K>1 boils off, K<1 stays in the liquid
y: vapour-phase mole fraction
x: liquid-phase mole fraction
z: overall feed mole fraction — what splits between the two phases
\psi: vapour fraction — the share of the feed that flashes to vapour (Rachford-Rice solves for it)
\gamma: liquid activity coefficient — the non-ideality correction; γ=1 is an ideal mixture, γ>1 means the components 'dislike' mixing and volatility rises
P^{sat}: pure-component vapour pressure [Pa] — how eager a pure component is to boil at this temperature
P: system pressure [Pa]
T: temperature [K]

pressure [Pa]; and one of temperature [K] OR duty [W] (default 0 = adiabatic)