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40 changes: 20 additions & 20 deletions Manuals/FDS_Technical_Reference_Guide/Appendices.tex
Original file line number Diff line number Diff line change
Expand Up @@ -846,22 +846,22 @@ \chapter{Analytical Jacobian Calculation for Detailed Chemical Mechanism}

The system of ODEs to solve a detailed chemical mechanism is given by Eqs.~(\ref{eq:chemistry_ode_system}) and (\ref{eq:TemperatureDerivative})
\begin{equation}\label{eq:chemistry_ode_system_appendix}
\frac{\d C_k}{\d t} = \dot{\omega}_k = \sum_{i=1}^{N_{\text{r}}} b_i \ \nu_{ki} \ r_i, j=1,2,3,...,N_{\text{s}}
\frac{\d C_k}{\d t} = \dot{\omega}_k = \sum_{i=1}^{N_{\rm r}} b_i \ \nu_{ki} \ r_i, j=1,2,3,...,N_{\rm s}
\end{equation}
\begin{equation}\label{eq:TemperatureDerivativeAppendix}
\frac{\d T}{\d t} = \dot{T} = -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\text{s}}}h_j W_j \dot{\omega}_j
\frac{\d T}{\d t} = \dot{T} = -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\rm s}}h_j W_j \dot{\omega}_j
\end{equation}
For Eq.~(\ref{eq:chemistry_ode_system_appendix}), $C_j$ is the molar concentration \si{(kmol/m^3)} of the $j$th species; $b_i$ is the reaction rate modification coefficient of the $i$th reaction due to third-body effects and pressure; $\nu_{ki} = {\nu}_{ki}^{''} - {\nu}_{ki}^{'}$; and $r_i$ is the reaction progress rate of the $i$th reaction.
\begin{equation}\label{eq:reaction_progress_rate_appendix}
r_i = k_{f,i} \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} - k_{r,i} \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}}
r_i = k_{f,i} \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} - k_{r,i} \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}}
\end{equation}
For Eq.~(\ref{eq:TemperatureDerivativeAppendix}), $\rho$ is the density \si{(kg/m^3)}, $c_p$ is the specific heat of the mixture (J/kg/K), $h_k$ is the absolute enthalpy that includes enthalpy of formation (J/kg), $W_j$ is the molecular weight (kg/kmol) of species $j$, and $\dot{\omega}$ is the species production rate given by Eq.~(\ref{eq:chemistry_ode_system_appendix}).

The system of ODEs can be represented by:
\be
\begin{aligned}
f &= \left[ \frac{\d C_1}{\d t} \ \frac{\d C_2}{\d t} \ldots \ \frac{\d C_{N_{\text{s}}}}{\d t} \ \frac{\d T}{\d t} \right]^T \
&= \left[ \dot{\omega}_1 \ \dot{\omega}_2 \ldots \ \dot{\omega}_{N_{\text{s}}} \ \dot{T} \right]^T \
f &= \left[ \frac{\d C_1}{\d t} \ \frac{\d C_2}{\d t} \ldots \ \frac{\d C_{N_{\rm s}}}{\d t} \ \frac{\d T}{\d t} \right]^T \
&= \left[ \dot{\omega}_1 \ \dot{\omega}_2 \ldots \ \dot{\omega}_{N_{\rm s}} \ \dot{T} \right]^T \
\end{aligned}
\ee

Expand All @@ -870,12 +870,12 @@ \chapter{Analytical Jacobian Calculation for Detailed Chemical Mechanism}
\begin{aligned}
J &=
\begin{bmatrix}
\frac{\partial\dot{\omega}_1}{\partial C_1}& \frac{\partial \dot{\omega}_2}{\partial C_1} & \ldots & \frac{\partial \dot{\omega}_{N_{\text{s}}}}{\partial C_1} & | & \frac{\partial \dot{T}}{\partial C_1}\\
\frac{\partial\dot{\omega}_1}{\partial C_2}& \frac{\partial \dot{\omega}_2}{\partial C_2} & \ldots & \frac{\partial \dot{\omega}_{N_{\text{s}}}}{\partial C_2} & | &\frac{\partial \dot{T}}{\partial C_2}\\
\frac{\partial\dot{\omega}_1}{\partial C_1}& \frac{\partial \dot{\omega}_2}{\partial C_1} & \ldots & \frac{\partial \dot{\omega}_{N_{\rm s}}}{\partial C_1} & | & \frac{\partial \dot{T}}{\partial C_1}\\
\frac{\partial\dot{\omega}_1}{\partial C_2}& \frac{\partial \dot{\omega}_2}{\partial C_2} & \ldots & \frac{\partial \dot{\omega}_{N_{\rm s}}}{\partial C_2} & | &\frac{\partial \dot{T}}{\partial C_2}\\
\ldots & \ldots & \ldots & \ldots & | & \ldots\\
\frac{\partial \dot{\omega}_1}{\partial C_{N_{\text{s}}}}& \frac{\partial \dot{\omega}_2}{\partial C_{N_{\text{s}}}} & \ldots & \frac{\partial \dot{\omega}_{N_{\text{s}}}}{\partial C_{N_{\text{s}}}} & | & \frac{\partial \dot{T}}{\partial C_{N_{\text{s}}}}\\
\frac{\partial \dot{\omega}_1}{\partial C_{N_{\rm s}}}& \frac{\partial \dot{\omega}_2}{\partial C_{N_{\rm s}}} & \ldots & \frac{\partial \dot{\omega}_{N_{\rm s}}}{\partial C_{N_{\rm s}}} & | & \frac{\partial \dot{T}}{\partial C_{N_{\rm s}}}\\
---& --- & --- & --- & | & ---\\
\frac{\partial \dot{\omega}_1}{\partial T}& \frac{\partial \dot{\omega}_2}{\partial T} & \ldots & \frac{\partial \dot{\omega}_{N_{\text{s}}}}{\partial T} & | & \frac{\partial \dot{T}}{\partial T}\\
\frac{\partial \dot{\omega}_1}{\partial T}& \frac{\partial \dot{\omega}_2}{\partial T} & \ldots & \frac{\partial \dot{\omega}_{N_{\rm s}}}{\partial T} & | & \frac{\partial \dot{T}}{\partial T}\\
\end{bmatrix}
&=\begin{bmatrix}
\frac{\partial \mathbf{\dot{\omega}}}{\mathbf{\partial C}}& \frac{\partial \dot{T}}{\partial \mathbf{C}}\\
Expand All @@ -888,16 +888,16 @@ \subsection*{Calculation of $\frac{\partial \mathbf{\dot{\omega}}}{\mathbf{\part
By taking derivative of Eq.~(\ref{eq:chemistry_ode_system_appendix}) with respect to concentration, we can write:
\begin{equation}\label{eq:Jac1st}
\begin{aligned}
\frac{\partial \dot{\omega}_k}{\partial C_l} &= \sum_{i=1}^{N_{reac}} \left[ \nu_{ki} \ r_i \ \frac{\partial b_i}{\partial C_l} + b_i \nu_{ki} \ \left( k_{f,i} \nu_{li}^{'} \ \frac{\prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} }{C_l} - k_{r,i} \ \nu_{li}^{''} \ \frac{\prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}} }{C_l} \right) \right],
\frac{\partial \dot{\omega}_k}{\partial C_l} &= \sum_{i=1}^{N_{reac}} \left[ \nu_{ki} \ r_i \ \frac{\partial b_i}{\partial C_l} + b_i \nu_{ki} \ \left( k_{f,i} \nu_{li}^{'} \ \frac{\prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} }{C_l} - k_{r,i} \ \nu_{li}^{''} \ \frac{\prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}} }{C_l} \right) \right],
\end{aligned}
\end{equation}
Here, the $\frac{\partial b_i}{\partial C_l}$ term can be calculated using Eqs.~(\ref{eq:reac_mod_coeff})-(\ref{eq:falloff_Fi}).

\subsection*{Calculation of $\frac{\partial \mathbf{\dot{\omega}}}{\partial T}$}
By taking derivative of Eq.~(\ref{eq:chemistry_ode_system_appendix}) with respect to temperature, we can write:
\begin{multline}\label{eq:Jac2nd}
\frac{\partial \dot{\omega}_k}{\partial T} = \sum_{i=1}^{N_{reac}} \left[ \nu_{ki} \ r_i \ \frac{\partial b_i}{\partial T} + b_i \nu_{ki} \ \left\{ \frac{\partial k_{f,i}}{\partial T} \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} + k_{f,i} \frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} \right) \right. \right. \\
- \left. \left. \frac{\partial k_{r,i}}{\partial T} \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}} - k_{r,i} \frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}} \right) \right\} \right]
\frac{\partial \dot{\omega}_k}{\partial T} = \sum_{i=1}^{N_{reac}} \left[ \nu_{ki} \ r_i \ \frac{\partial b_i}{\partial T} + b_i \nu_{ki} \ \left\{ \frac{\partial k_{f,i}}{\partial T} \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} + k_{f,i} \frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} \right) \right. \right. \\
- \left. \left. \frac{\partial k_{r,i}}{\partial T} \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}} - k_{r,i} \frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}} \right) \right\} \right]
\end{multline}
Similar to $\frac{\partial b_i}{\partial C_l}$, $\frac{\partial b_i}{\partial T}$ can be calculated using Eqs.~(\ref{eq:reac_mod_coeff})-(\ref{eq:falloff_Fi}).
\begin{equation} \label{eq:kfTmpDerivative}
Expand All @@ -912,14 +912,14 @@ \subsection*{Calculation of $\frac{\partial \mathbf{\dot{\omega}}}{\partial T}$}
Here, $K_i$ is the concentration equilibrium constant obtained using Eq.~(\ref{eq:equilibrium_const}). Through mathematical derivation, it can be shown that:
\begin{equation}\label{eq:EqConstTmpDerivative}
\begin{aligned}
\frac{1}{K_i} \frac{\partial K_i}{\partial T} = -\frac{1}{T} \left( \sum_{i=1}^{N_{\text{s}}} {\nu}_{ji}^{''} - \sum_{i=1}^{N_{\text{s}}} {\nu}_{ji}^{'} \right) + \frac{1}{R T} \left( \frac{\Delta G_{\mathrm{rxn}}}{T} + \Delta S_{\mathrm{rxn}} \right)
\frac{1}{K_i} \frac{\partial K_i}{\partial T} = -\frac{1}{T} \left( \sum_{i=1}^{N_{\rm s}} {\nu}_{ji}^{''} - \sum_{i=1}^{N_{\rm s}} {\nu}_{ji}^{'} \right) + \frac{1}{R T} \left( \frac{\Delta G_{\mathrm{rxn}}}{T} + \Delta S_{\mathrm{rxn}} \right)
\end{aligned}
\end{equation}
Here, $\Delta S_{\mathrm{rxn}}$ is the change in entropy, and can be calculated similar to the process described in Section \ref{sec:equilChem}.
\begin{equation}\label{eq:ConcTmpDerivative}
\begin{aligned}
\frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} \right) &= - \frac{1}{T} \left( \sum_{j=1}^{N_{\text{s}}} {\nu}_{ji}^{'} \right) \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{'}} \right) \\
\frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}} \right) &= - \frac{1}{T} \left( \sum_{j=1}^{N_{\text{s}}} {\nu}_{ji}^{''} \right) \left( \prod_{j=1}^{N_{\text{s}}} (C_j)^{{\nu}_{ji}^{''}} \right){}
\frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} \right) &= - \frac{1}{T} \left( \sum_{j=1}^{N_{\rm s}} {\nu}_{ji}^{'} \right) \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{'}} \right) \\
\frac{\partial}{\partial T} \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}} \right) &= - \frac{1}{T} \left( \sum_{j=1}^{N_{\rm s}} {\nu}_{ji}^{''} \right) \left( \prod_{j=1}^{N_{\rm s}} (C_j)^{{\nu}_{ji}^{''}} \right){}
\end{aligned}
\end{equation}
In the above derivation, the relation $\frac{\partial C_j}{\partial T} = - \frac{C_j}{T}$ is used.
Expand All @@ -930,22 +930,22 @@ \subsection*{Calculation of $\frac{\partial \dot{T}}{\partial \mathbf{C}}$}
By taking derivative of Eq.~(\ref{eq:TemperatureDerivativeAppendix}) with respect to concentration, we can write:
\begin{equation} \label{eq:Jac3rd}
\begin{aligned}
\frac{\partial \dot{T}}{\partial C_l} &= \frac{\partial}{\partial C_l} \left( -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\text{s}}}h_j W_j \dot{\omega}_j \right) \\
&= -\left( \frac{1}{\rho} \frac{\partial \rho}{\partial C_l} + \frac{1}{c_p} \frac{\partial c_p}{\partial C_l} \right) \dot{T} - \frac{1}{{\rho} c_p} \sum_{j=1}^{N_{\text{s}}}h_j W_j \frac{\partial \dot{\omega}_j}{\partial C_l}
\frac{\partial \dot{T}}{\partial C_l} &= \frac{\partial}{\partial C_l} \left( -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\rm s}}h_j W_j \dot{\omega}_j \right) \\
&= -\left( \frac{1}{\rho} \frac{\partial \rho}{\partial C_l} + \frac{1}{c_p} \frac{\partial c_p}{\partial C_l} \right) \dot{T} - \frac{1}{{\rho} c_p} \sum_{j=1}^{N_{\rm s}}h_j W_j \frac{\partial \dot{\omega}_j}{\partial C_l}
\end{aligned}
\end{equation}
Using the relations $\frac{\partial \rho}{\partial C_l} = W_l$ and $\frac{\partial c_p}{\partial C_l} = - \frac{W_l}{\rho}\left( c_p -c_{p,l} \right)$, we can rewrite Eq. ~(\ref{eq:Jac3rd}) as:
\begin{equation} \label{eq:Jac3rd_final}
\frac{\partial \dot{T}}{\partial C_l} = \frac{W_l c_{p,l}}{\rho c_p} \dot{T} - \frac{1}{{\rho} c_p} \sum_{j=1}^{N_{\text{s}}}h_j W_j \frac{\partial \dot{\omega}_j}{\partial C_l}
\frac{\partial \dot{T}}{\partial C_l} = \frac{W_l c_{p,l}}{\rho c_p} \dot{T} - \frac{1}{{\rho} c_p} \sum_{j=1}^{N_{\rm s}}h_j W_j \frac{\partial \dot{\omega}_j}{\partial C_l}
\end{equation}
Here, $c_{p,l}$ is the specific heat of species $l$. The last term Eq.~(\ref{eq:Jac3rd_final}) can be obtained using Eq. \ref{eq:Jac1st}.

\subsection*{Calculation of $\frac{\partial \dot{T}}{\partial T}$}
By taking derivative of Eq.~(\ref{eq:TemperatureDerivativeAppendix}) with respect to temperature, we can write:
\begin{equation} \label{eq:Jac4th}
\begin{aligned}
\frac{\partial \dot{T}}{\partial T} &= \frac{\partial}{\partial T} \left( -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\text{s}}}h_j W_j \dot{\omega}_j \right) \\
&=\frac{\dot{T}}{T} - \frac{1}{c_p} \frac{\partial c_p}{\partial T} \dot{T} - \frac{1}{\rho c_p} \sum_{j=1}^{N_{\text{s}}} \left[ h_j \frac{\partial \dot{\omega}_j}{\partial T} + \dot{\omega}_j c_{p,j} \right] W_j
\frac{\partial \dot{T}}{\partial T} &= \frac{\partial}{\partial T} \left( -\frac{1}{\rho c_p} \sum_{j=1}^{N_{\rm s}}h_j W_j \dot{\omega}_j \right) \\
&=\frac{\dot{T}}{T} - \frac{1}{c_p} \frac{\partial c_p}{\partial T} \dot{T} - \frac{1}{\rho c_p} \sum_{j=1}^{N_{\rm s}} \left[ h_j \frac{\partial \dot{\omega}_j}{\partial T} + \dot{\omega}_j c_{p,j} \right] W_j
\end{aligned}
\end{equation}
To derive the above equation, the relations $\frac{\partial \rho}{\partial T} = -\frac{\rho}{T}$ and $\frac{\partial h_j}{\partial T} = c_{p,j}$ are used. The term $\frac{\partial \dot{\omega}_j}{\partial T}$ can be obtained using Eq.~(\ref{eq:Jac2nd}).
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