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Copy file name to clipboardExpand all lines: Manuals/FDS_User_Guide/FDS_User_Guide.tex
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@@ -10205,7 +10205,8 @@ \subsection{Heat Release Rate and Energy Conservation}
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\end{eqnarray}
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\begin{description}
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\item[{\ct Q\_ENTH}] The change in the sensible enthalpy of the gas. $\rho$ is the density of the gas (kg/m$^3$). $h_{\rm s}$ is the \underline{s}ensible enthalpy of the gas (kJ/kg). The volume integral is over the entire domain.
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\item[{\ct HRR}] The total heat release rate of the fire (kW). By default the effects of any surface oxidation reactions are included in this value. This helps when comparing to heat release measurements obtained from oxygen consumption calorimetry, as the additional oxygen sink from surface reactions will be lumped into the measurement. However, it is possible to output only the contribution from gas-phase combustion by setting {\ct HRR\_GAS\_ONLY=T} on the {\ct DUMP} line.
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\item[{\ct HRR}] The heat release rate of the fire (kW) resulting from gas phase combustion.
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\item[{\ct HRR\_OX}] The heat release rate (kW) of any surface oxidation reactions. This helps when comparing to heat release measurements obtained from oxygen consumption calorimetry, as the additional oxygen sink from surface reactions will be lumped into the measurement.
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\item[{\ct Q\_RADI}] The thermal radiation {\em into} the domain from the exterior boundary or particles. $\dot{\bq}_{\rm r}''$ is the \underline{r}adiation heat flux vector (\unit{kW/m^2}). Its divergence represents the net radiative emission from a volume of gas. Typically, {\ct Q\_RADI} has a negative value, meaning that a fire or hot gases radiate energy out of the domain. $\dq_{\rm p,r}$ is the \underline{r}adiation absorbed by a droplet or \underline{p}article (kW). This term is added to {\ct Q\_RADI} and subtracted from {\ct Q\_PART} because it is implicitly included in $\nabla \cdot \dot{\bq}_{\rm r}''$ and needs to be separated off for the purpose of explicitly accounting for it in the energy budget.
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\item[{\ct Q\_CONV}] The flow of sensible enthalpy {\em into} the computational domain. $\dm_{\rm p,\alpha}$ is the production rate of gas species $\alpha$ from a solid \underline{p}article or liquid droplet (kg/s). $h_{\rm s,\alpha}$ is the \underline{s}ensible enthalpy of gas species $\alpha$ (kJ/kg). $\rho$ is the gas density (kg/m$^3$), $\bu$ is the velocity vector (m/s). $h_{\rm s}$ is the \underline{s}ensible enthalpy of the gas. If the gas is flowing out of the domain, $\bu \cdot \d {\bf S}$ is positive.
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\item[{\ct Q\_COND}] The convective heat flux {\em into} the computational domain. $\dq_{\rm c}''$ is the heat \underline{c}onvected from the gas to a surface. If the gas is relatively hot and the surfaces/particles/droplets relatively cool, {\ct Q\_COND} is negative. At {\ct OPEN} boundaries, {\ct Q\_COND} is $\int k \nabla T \cdot \d {\bf S}$, where $k$ (kW/(m$\cdot$K)) is the turbulent thermal conductivity of the gas and $\nabla T$ is the temperature gradient across the open boundary. $\dq_{\rm p,w}$ is the energy transferred from a solid surface (\underline{w}all) to a droplet or \underline{p}article adhering to it. Notice that it is subtracted off in {\ct Q\_PART} because it makes no contribution to the energy of the gas.
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