Merge remote-tracking branch 'firemodels/master' into FireX

Manuals/Bibliography/FDS_general.bib

@@ -2785,6 +2785,16 @@ @ARTICLE{Hu:2005
   year         = {2005},
 }
 
+@ARTICLE{Huang:1963,
+  author       = {G.C. Huang},
+  title        = {{Investigations of Heat-Transfer Coefficients for Air Flow Through}},
+  journal      = {J. Heat Transfer},
+  volume       = 85,
+  number       = 3,
+  pages        = {237-245},
+  year         = 1963
+}
+
 @ARTICLE{Huggett:1,
   author       = {Huggett, C.},
   title        = {{Estimation of Rate of Heat Release by
@@ -3429,6 +3439,16 @@ @INPROCEEDINGS{Liou:1
   pages        = {1131-1138},
 }
 
+@TECHREPORT{Livingood:1973,
+  author       = {Livingood, J.N.B. and Hrycak, P.},
+  title        = {{Impingement Heat Transfer from Turbulent Air Jets to Flat Plates - A Literature Survey}},
+  type         = {NASA Tehnical Memorandum},
+  number       = {1973},
+  institution  = {National Aeronautics and Space Administration},
+  address      = {Washington, D.C.},
+  year         = {May 1973}
+}
+
 @TECHREPORT{Lock:1,
   author       = {Lock, A. and Bundy, M. and Johnsson, E.L. and Hamins, A. and Ko, G.H. and Hwang, C. and Fuss, P. and Harris, R.},
   title        = {{Experimental Study of the Effects of Fuel Type, Fuel Distribution, and Vent Size on Full-Scale Underventilated Compartment Fires in an ISO 9705 Room }},
@@ -3765,6 +3785,17 @@ @TECHREPORT{Maranghides:TN2235
   address      = {Gaithersburg, Maryland},
 }
 
+@INBOOK{Martin:1977,
+  author       = {H. Martin},
+  title        = {Advances in Heat Transfer},
+  editor       = {J.P Hartnett and T.F. Irvine, Jr.},
+  chapter      = {Heat and Mass Transfer Between Impinging Gas Jets and Solid Surfaces},
+  publisher    = {Academic Press},
+  year         = {1977},
+  volume       = {13},
+  address      = {New York}
+}
+
 @INPROCEEDINGS{May:2014,
   author       = {May, Sandra and Berger, Marsha},
   title        = {A mixed explicit implicit time stepping scheme for Cartesian embedded boundary meshes},

Manuals/FDS_Technical_Reference_Guide/Solid_Chapter.tex

@@ -145,6 +145,12 @@ \subsubsection{Empirical Natural/Forced Convection Model}
 \end{center}
 \end{table}
 
+The impinging jet heat transfer model uses the stagnation pressure to define the velocity scale, $U_{\rm imp} = \sqrt{2 H}$, in the Reynolds number, but otherwise uses the forced convection Nusselt correlation with slightly modified default constants, $C_1 = 0.55$ and $n=0.8$.  As with the forced convection model, custom coefficients may be used, as discussed in the FDS User Guide \cite{FDS_Users_Guide}.  If the impinging jet model is implemented by the user, $\NU_{\rm impinge}$ gets added to the list of max arguments in Eq.~(\ref{q_con}).
+
+\be
+   \NU_{\rm impinge} = C_0 + \left( C_1 \, \RE_{\rm imp}^n - C_2 \right) \, \PR^m  \quad ; \quad \RE_{\rm imp} = \frac{\rho U_{\rm imp} L}{\mu}  \quad ; \quad m=1/3
+\ee
+
 
 \subsubsection{Optional Near-Wall Model}
 \label{conflux_wall_model}

Manuals/FDS_Verification_Guide/FDS_Verification_Guide.tex

@@ -2162,6 +2162,31 @@ \subsection{Sphere (\texorpdfstring{\textct{free\_conv\_sphere}}{free\_conv\_sph
 \end{figure}
 
 
+\clearpage
+\section{Impinging Jet (\texorpdfstring{\textct{impinging\_jet}}{impinging\_jet})}
+\label{sec:impinging_jet}
+
+Impinging jet flow poses a challenge for convective heat transfer models because the stagnation velocity goes to zero numerically near the mean stagnation point and hence the computed Reynolds number is fictitiously low leading to an under-prediction of the local heat transfer coefficient.  To handle this problem, the user may specify a special impinging jet heat transfer model, as discussed in the FDS User Guide \cite{FDS_Users_Guide}, which basically uses the forced convection correlation but with a velocity scale obtained from the stagnation pressure, following Huang \cite{Huang:1963,Livingood:1973}.  In this section, we present results from a series of cases designed to confirm the general trend that the highest heat transfer coefficient is found at the stagnation point.  There is no analytical solution to this case.  We take our target correlation to be that of Martin \cite{Martin:1977,Incropera:1}.  The default coefficients of the impinging jet model have been tuned to match the Martin correlation for the specific case discussed below at coarse grid resolution.
+
+The set up for the problem is a simple cubic domain 1 m on a side.  The lateral boundaries are open.  The top boundary is held at a fixed 20 C.  A hot jet of air is injected from a 0.2 m by 0.2 m square vent at 100 C.  Two Reynolds numbers are considered by changing the inlet flow velocity [10, 40] m/s.  Three grid resolutions for each Reynolds number are tested, $D/\delta x$ = [7, 14, 28], representing \emph{coarse}, \emph{medium}, and \emph{fine} resolutions.  The cases are fun for roughly flow through times with statistics collected over the last half of the simulation.
+
+Figure \ref{fig_impinging_jet_corr} shows FDS results for three grid resolutions compared to the correlation in Martin \cite{Martin:1977,Incropera:1}.  The plots below in Fig.~\ref{fig_impinging_jet_prof} show the profile of Nu along the ceiling.
+
+\begin{figure}[h]
+   \centering
+   \includegraphics[height=2.2in]{SCRIPT_FIGURES/impinging_jet_correlation}
+   \caption[Impinging jet Nusselt correlation]{\label{fig_impinging_jet_corr} Average Nusselt number correlation for a flat plate compared to FDS results using the impinging jet heat transfer model.}
+\end{figure}
+
+\begin{figure}[h]
+   \centering
+   \begin{tabular*}{\textwidth}{lr}
+       \includegraphics[height=2.2in]{SCRIPT_FIGURES/impinging_jet_local_Re_1e5} &
+       \includegraphics[height=2.2in]{SCRIPT_FIGURES/impinging_jet_local_Re_4e5} \\
+   \end{tabular*}
+   \caption[Impinging jet Nusselt profile]{\label{fig_impinging_jet_prof} Profile of average Nusselt number (Nu) along the ceiling at Reynolds numbers (Re) based on jet diameter of $1 \times 10^5$ (left) and $4 \times 10^5$.}
+\end{figure}
+
 \clearpage
 \section{Ribbed Square Duct Flow (\texorpdfstring{\textct{ribbed\_channel}}{ribbed\_channel})}
 \label{sec:ribbed_channel}

Source/dump.f90

@@ -8752,7 +8752,7 @@ REAL(EB) FUNCTION SOLID_PHASE_OUTPUT(NM,INDX,Y_INDEX,Z_INDEX,PART_INDEX,OPT_WALL
 INTEGER, INTENT(IN), OPTIONAL :: OPT_WALL_INDEX,OPT_LP_INDEX,OPT_CFACE_INDEX,OPT_BNDF_INDEX,OPT_DEVC_INDEX,OPT_CUT_FACE_INDEX,&
                                  OPT_NODE_INDEX,OPT_PROF_INDEX
 INTEGER, INTENT(IN) :: INDX,Y_INDEX,Z_INDEX,PART_INDEX,NM
-REAL(EB) :: Q_CON,VOLSUM,MFT,ZZ_GET(1:N_TRACKED_SPECIES),Y_SPECIES,DEPTH,UN,H_S,RHO_D_DYDN,U_CELL,V_CELL,W_CELL,&
+REAL(EB) :: Q_CON,RHOSUM,VOLSUM,MFT,ZZ_GET(1:N_TRACKED_SPECIES),Y_SPECIES,DEPTH,UN,H_S,RHO_D_DYDN,U_CELL,V_CELL,W_CELL,&
             LTMP,ATMP,CTMP,H_W_EFF,X0,X1,XC0,XC1,TMP_BAR,VOL,DVOL,DN,PRESS,&
             NVEC(3),PVEC(3),TAU_IJ(3,3),VEL_CELL(3),VEL_WALL(3),MU_WALL,RHO_WALL,FVEC(3),SVEC(3),TVEC1(3),TVEC2(3),&
             PR1,PR2,Z1,Z2,RADIUS,CUT_FACE_AREA,SOLID_PHASE_OUTPUT_CTF,AAA,BBB,CCC,ALP,BET,GAM,MMM,DTMP
@@ -9118,10 +9118,10 @@ REAL(EB) FUNCTION SOLID_PHASE_OUTPUT(NM,INDX,Y_INDEX,Z_INDEX,PART_INDEX,OPT_WALL
             RETURN
          ENDIF
          IF (ONE_D%MATL_COMP(NN)%RHO(II1)<=TWO_EPSILON_EB) CYCLE MATERIAL_LOOP_CP
+         RHOSUM = RHOSUM + ONE_D%MATL_COMP(NN)%RHO(II1)
          ML  => MATERIAL(SF%MATL_INDEX(NN))
-         VOLSUM = VOLSUM + ONE_D%MATL_COMP(NN)%RHO(II1)/SF%RHO_S(SF%LAYER_INDEX(II1),NN)
          ITMP = MIN(I_MAX_TEMP,NINT(ONE_D%TMP(II1)))
-         SOLID_PHASE_OUTPUT = SOLID_PHASE_OUTPUT + ONE_D%MATL_COMP(NN)%RHO(II1)*ML%C_S(ITMP)/SF%RHO_S(SF%LAYER_INDEX(II1),NN)
+         SOLID_PHASE_OUTPUT = SOLID_PHASE_OUTPUT + ONE_D%MATL_COMP(NN)%RHO(II1)*ML%C_S(ITMP)
       ENDDO MATERIAL_LOOP_CP
       SOLID_PHASE_OUTPUT = SOLID_PHASE_OUTPUT / VOLSUM * 0.001_EB