From d13a4641ce899c9d61199513a477d6fb9e4777fa Mon Sep 17 00:00:00 2001
From: Ian Bell <ian.bell@nist.gov>
Date: Thu, 15 Sep 2022 10:07:57 -0600
Subject: [PATCH] Add example of calling superancillary for PC-SAFT to docs
---
doc/source/models/PCSAFT.ipynb | 46 +++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/doc/source/models/PCSAFT.ipynb b/doc/source/models/PCSAFT.ipynb
index 973f43b..57dfb23 100644
--- a/doc/source/models/PCSAFT.ipynb
+++ b/doc/source/models/PCSAFT.ipynb
@@ -104,7 +104,51 @@
"source": [
"## Superancillary\n",
"\n",
- "The superancillary equation for PC-SAFT has been developed, and is much more involved than that of the cubic EOS. As a consequence, the superancillary equation has been provided as a separate package rather than integrating it into to teqp to minimize the binary size of teqp. It can be installed from PYPI with: ``pip install PCSAFTsuperanc``"
+ "The superancillary equation for PC-SAFT has been developed, and is much more involved than that of the cubic EOS. As a consequence, the superancillary equation has been provided as a separate package rather than integrating it into to teqp to minimize the binary size of teqp. It can be installed from PYPI with: ``pip install PCSAFTsuperanc``\n",
+ "\n",
+ "The scaling in the superancillaries uses reduced variables:\n",
+ "\n",
+ "$$ \\tilde T = T/(\\epsilon/k_{\\rm B}) $$\n",
+ "$$ \\tilde\\rho = \\rho_{\\rm N}\\sigma^3 $$\n",
+ "\n",
+ "where $\\rho_{\\rm N}$ is the number density, and the other parameters are from the PC-SAFT model"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "f6e3b8d2",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "import PCSAFTsuperanc\n",
+ "\n",
+ "sigma_m = 3e-10 # [meter]\n",
+ "e_over_k = 150.0 # [K]\n",
+ "m = 5\n",
+ "\n",
+ "# The saturation temperature\n",
+ "T = 300\n",
+ "\n",
+ "[Ttilde_crit, Ttilde_min] = PCSAFTsuperanc.get_Ttilde_crit_min(m=m)\n",
+ "print('Ttilde crit:', Ttilde_crit)\n",
+ "\n",
+ "# Get the scaled densities for liquid and vapor phases\n",
+ "[tilderhoL, tilderhoV] = PCSAFTsuperanc.PCSAFTsuperanc_rhoLV(Ttilde=T/e_over_k, m=m)\n",
+ "# Convert back to molar densities\n",
+ "N_A = PCSAFTsuperanc.N_A # The value of Avogadro's constant used in superancillaries\n",
+ "rhoL, rhoV = [tilderho/(N_A*sigma_m**3) for tilderho in [tilderhoL, tilderhoV]]\n",
+ "\n",
+ "# As a sanity check, confirm that we got the same pressure in both phases\n",
+ "c = teqp.SAFTCoeffs()\n",
+ "c.sigma_Angstrom = sigma_m*1e10\n",
+ "c.epsilon_over_k = e_over_k \n",
+ "c.m = m\n",
+ "model = teqp.PCSAFTEOS([c])\n",
+ "z = np.array([1.0])\n",
+ "pL = rhoL*model.get_R(z)*T*(1+model.get_Ar01(T, rhoL, z))\n",
+ "pV = rhoV*model.get_R(z)*T*(1+model.get_Ar01(T, rhoV, z))\n",
+ "print('Pressures are:', pL, pV, 'Pa')"
]
},
{
--
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