From d33490f16b932c6b3d63b5d7a54a852fde0a6687 Mon Sep 17 00:00:00 2001
From: Thomas Fetzer <thomas.fetzer@iws.uni-stuttgart.de>
Date: Thu, 16 Nov 2017 12:14:55 +0100
Subject: [PATCH] [components] Introduce heat capacity functions, use them to
calculate enthalpy
Nitrogen already had a heat capacity function, however, it was calculated differently for the other gases.
---
dumux/material/components/ch4.hh | 33 ++++++++++-------
dumux/material/components/h2.hh | 29 +++++++++------
dumux/material/components/n2.hh | 40 +++++----------------
dumux/material/components/o2.hh | 31 ++++++++++------
dumux/material/fluidsystems/h2on2kinetic.hh | 2 +-
5 files changed, 70 insertions(+), 65 deletions(-)
diff --git a/dumux/material/components/ch4.hh b/dumux/material/components/ch4.hh
index fe095eec15..65c7be37ff 100644
--- a/dumux/material/components/ch4.hh
+++ b/dumux/material/components/ch4.hh
@@ -132,13 +132,26 @@ public:
/*!
* \brief Specific enthalpy \f$\mathrm{[J/kg]}\f$ of pure methane gas.
*
- * \param T temperature of component in \f$\mathrm{[K]}\f$
+ * \param temperature temperature of component in \f$\mathrm{[K]}\f$
* \param pressure pressure of component in \f$\mathrm{[Pa]}\f$
- *
- * See: R. Reid, et al. (1987, pp 154, 657, 671) \cite reid1987
*/
- static const Scalar gasEnthalpy(Scalar T,
+ static const Scalar gasEnthalpy(Scalar temperature,
Scalar pressure)
+ {
+ return gasHeatCapacity(temperature, pressure) * temperature;
+ }
+
+ /*!
+ * \brief Specific isobaric heat capacity \f$\mathrm{[J/(kg*K)]}\f$ of pure
+ * methane gas.
+ *
+ * This is equivalent to the partial derivative of the specific
+ * enthalpy to the temperature.
+ *
+ * See: R. Reid, et al. (1987, pp 154, 657, 665) \cite reid1987
+ */
+ static Scalar gasHeatCapacity(Scalar T,
+ Scalar pressure)
{
// method of Joback
const Scalar cpVapA = 19.25;
@@ -146,16 +159,12 @@ public:
const Scalar cpVapC = 1.197e-5;
const Scalar cpVapD = -1.132e-8;
- //Scalar cp =
- // cpVapA + T*(cpVapB + T*(cpVapC + T*cpVapD));
-
- // calculate: \int_0^T c_p dT
return
- 1/molarMass()* // conversion from [J/mol] to [J/kg]
- T*(cpVapA + T*
- (cpVapB/2 + T*
+ 1/molarMass()* // conversion from [J/(mol*K)] to [J/(kg*K)]
+ (cpVapA + T*
+ (cpVapB/2 + T*
(cpVapC/3 + T*
- (cpVapD/4))));
+ (cpVapD/4))));
}
/*!
diff --git a/dumux/material/components/h2.hh b/dumux/material/components/h2.hh
index 65af6a93c0..32e7d43b9b 100644
--- a/dumux/material/components/h2.hh
+++ b/dumux/material/components/h2.hh
@@ -146,13 +146,26 @@ public:
/*!
* \brief Specific enthalpy \f$\mathrm{[J/kg]}\f$ of pure hydrogen gas.
*
- * \param T temperature of component in \f$\mathrm{[K]}\f$
+ * \param temperature temperature of component in \f$\mathrm{[K]}\f$
* \param pressure pressure of component in \f$\mathrm{[Pa]}\f$
+ */
+ static const Scalar gasEnthalpy(Scalar temperature,
+ Scalar pressure)
+ {
+ return gasHeatCapacity(temperature, pressure) * temperature;
+ }
+
+ /*!
+ * \brief Specific isobaric heat capacity \f$\mathrm{[J/(kg*K)]}\f$ of pure
+ * hydrogen gas.
+ *
+ * This is equivalent to the partial derivative of the specific
+ * enthalpy to the temperature.
*
* See: R. Reid, et al. (1987, pp 154, 657, 665) \cite reid1987
*/
- static const Scalar gasEnthalpy(Scalar T,
- Scalar pressure)
+ static const Scalar gasHeatCapacity(Scalar T,
+ Scalar pressure)
{
// method of Joback
const Scalar cpVapA = 27.14;
@@ -160,14 +173,10 @@ public:
const Scalar cpVapC = -1.381e-5;
const Scalar cpVapD = 7.645e-9;
- //Scalar cp =
- // cpVapA + T*(cpVapB + T*(cpVapC + T*cpVapD));
-
- // calculate: \int_0^T c_p dT
return
- 1/molarMass()* // conversion from [J/mol] to [J/kg]
- T*(cpVapA + T*
- (cpVapB/2 + T*
+ 1/molarMass()* // conversion from [J/(mol*K)] to [J/(kg*K)]
+ (cpVapA + T*
+ (cpVapB/2 + T*
(cpVapC/3 + T*
(cpVapD/4))));
}
diff --git a/dumux/material/components/n2.hh b/dumux/material/components/n2.hh
index b9da95dce7..b0d5724008 100644
--- a/dumux/material/components/n2.hh
+++ b/dumux/material/components/n2.hh
@@ -160,36 +160,13 @@ public:
/*!
* \brief Specific enthalpy \f$\mathrm{[J/kg]}\f$ of pure nitrogen gas.
*
- * \param T temperature of component in \f$\mathrm{[K]}\f$
+ * \param temperature temperature of component in \f$\mathrm{[K]}\f$
* \param pressure pressure of component in \f$\mathrm{[Pa]}\f$
- *
- * See: R. Reid, et al. (1987, pp 154, 657, 665) \cite reid1987
*/
- static const Scalar gasEnthalpy(Scalar T,
+ static const Scalar gasEnthalpy(Scalar temperature,
Scalar pressure)
{
- // method of Joback
- const Scalar cpVapA = 31.15;
- const Scalar cpVapB = -0.01357;
- const Scalar cpVapC = 2.680e-5;
- const Scalar cpVapD = -1.168e-8;
-
- // calculate: \int_0^T c_p dT
- return
- 1/molarMass()* // conversion from [J/(mol K)] to [J/(kg K)]
-
- T*(cpVapA + T*
- (cpVapB/2 + T*
- (cpVapC/3 + T*
- (cpVapD/4))));
-
-//#warning NIST DATA STUPID INTERPOLATION
-// Scalar T2 = 300.;
-// Scalar T1 = 285.;
-// Scalar h2 = 311200.;
-// Scalar h1 = 295580.;
-// Scalar h = h1+ (h2-h1) / (T2-T1) * (T-T1);
-// return h ;
+ return gasHeatCapacity(temperature, pressure) * temperature;
}
/*!
@@ -220,6 +197,8 @@ public:
*
* This is equivalent to the partial derivative of the specific
* enthalpy to the temperature.
+ *
+ * See: R. Reid, et al. (1987, pp 154, 657, 665) \cite reid1987
*/
static const Scalar gasHeatCapacity(Scalar T,
Scalar pressure)
@@ -232,11 +211,10 @@ public:
return
1/molarMass()* // conversion from [J/(mol K)] to [J/(kg K)]
-
- cpVapA + T*
- (cpVapB + T*
- (cpVapC + T*
- (cpVapD)));
+ (cpVapA + T*
+ (cpVapB/2 + T*
+ (cpVapC/3 + T*
+ (cpVapD/4))));
}
/*!
diff --git a/dumux/material/components/o2.hh b/dumux/material/components/o2.hh
index 0ecb4a4daa..6b7ab93f2b 100644
--- a/dumux/material/components/o2.hh
+++ b/dumux/material/components/o2.hh
@@ -158,13 +158,26 @@ public:
/*!
* \brief Specific enthalpy \f$\mathrm{[J/kg]}\f$ of pure oxygen gas.
*
- * \param T temperature of component in \f$\mathrm{[K]}\f$
+ * \param temperature temperature of component in \f$\mathrm{[K]}\f$
* \param pressure pressure of component in \f$\mathrm{[Pa]}\f$
+ */
+ static Scalar gasEnthalpy(Scalar temperature,
+ Scalar pressure)
+ {
+ return gasHeatCapacity(temperature, pressure) * temperature;
+ }
+
+ /*!
+ * \brief Specific isobaric heat capacity \f$\mathrm{[J/(kg*K)]}\f$ of pure
+ * oxygen gas.
+ *
+ * This is equivalent to the partial derivative of the specific
+ * enthalpy to the temperature.
*
* See: R. Reid, et al. (1987, pp 154, 657, 665) \cite reid1987
*/
- static Scalar gasEnthalpy(Scalar T,
- Scalar pressure)
+ static Scalar gasHeatCapacity(Scalar T,
+ Scalar pressure)
{
// method of Joback
const Scalar cpVapA = 28.11;
@@ -172,16 +185,12 @@ public:
const Scalar cpVapC = 1.746e-5;
const Scalar cpVapD = -1.065e-8;
- //Scalar cp =
- // cpVapA + T*(cpVapB + T*(cpVapC + T*cpVapD));
-
- // calculate: \int_0^T c_p dT
return
- 1/molarMass()* // conversion from [J/mol] to [J/kg]
- T*(cpVapA + T*
- (cpVapB/2 + T*
+ 1/molarMass()* // conversion from [J/(mol*K)] to [J/(kg*K)]
+ (cpVapA + T*
+ (cpVapB/2 + T*
(cpVapC/3 + T*
- (cpVapD/4))));
+ (cpVapD/4))));
}
/*!
diff --git a/dumux/material/fluidsystems/h2on2kinetic.hh b/dumux/material/fluidsystems/h2on2kinetic.hh
index 3559b675e6..f635e7ab17 100644
--- a/dumux/material/fluidsystems/h2on2kinetic.hh
+++ b/dumux/material/fluidsystems/h2on2kinetic.hh
@@ -90,7 +90,7 @@ public:
case ParentType::H2OIdx:
return ParentType::H2O::liquidEnthalpy(T, p);
case ParentType::N2Idx:
- return ParentType::N2::gasEnthalpy(T, p);
+ return ParentType::N2::gasEnthalpy(T, p); // TODO: should be liquid enthalpy
default:
DUNE_THROW(Dune::NotImplemented,
"wrong index");
--
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