Hi everyone,
I went through the case of "cfdemSolverPisoScalar packedBedTemp CFD" and found some usefull topics from the forum. but I still have one big question about the case. how is The DEM data in DEM folder used in CFD simulation? in totalPressureDropAndNusselt.m of ....CFD/octave/ ?. But in this file (.m), the properties about particles were given by constants. The only changing parameters are P and T which come from the " /postProcessing/probes/0/T' and 0/P' " and are given before the calculation. In the dumping file from DEM, just the f_Temp[0] f_heatFlux[0] two parameter were output. Thanks in adance.
yyu
appendix The totalPressureDropAndNusselt.m files:
close all;
clear;
clc;
%*********************************************************************%
% pressure drop
%*********************************************************************%
%===================
% Ergun Equation
%===================
fprintf('\ncalc Ergun eqn:\n')
dp = 0.022; % particle diameter
phip = 1; % sphericity
epsilon = 0.4436; % voidfraction
U = 1; % superficial velocity
L = 1; % length of bed
rhoG = 1.188; % density in kg/m
nuG = 1.5e-3; % kinemat Visk in m2/s
muG = nuG*rhoG % dynam visc in Pa s
dpErgun= L * (
150*((1-epsilon)^2/epsilon^3)*((muG*U)/(phip*dp)^2)
+1.75*((1-epsilon)/epsilon^3)*((rhoG*U^2)/(phip*dp))
)
fprintf('final pressure drop = %f Pa\n',dpErgun)
%====================================%
% simulation data
%====================================%
path = '/home/yyu/CFDEM/CFDEMcoupling-PUBLIC-2.2.x/tutorials/cfdemSolverPiso/ErgunTestMPI/CFD/postProcessing/probes/0/p';
columns=3;
headerlines=5;
data = loaddata(path,columns,headerlines);
data=transpose(data);
[x,y]=size(data);
dp_sim = data(:,2)-data(:,y);
t_sim = data(:,1);
fprintf('final pressureDrop of sim = %f Pa\n',dp_sim(length(dp_sim)) )
%====================================%
% plot data
%====================================%
figure(1)
plot(t_sim,dpErgun*ones(1,length(t_sim)),t_sim,dp_sim)
axis([0,0.7,0,dpErgun(length(dpErgun))])
title("Ergun pressure drop")
legend("analytical - Ergun","simulation")
%print('cfdemSolverPiso_settlingTest.eps','-deps2')
print -color "cfdemSolverPisoScalar_pressureDrop.eps"
replot;
%*********************************************************************%
% heat transfer
%*********************************************************************%
%====================================%
% simulation data
%====================================%
cp = 1007;
A = 0.01;
U = U;
alpha = epsilon;
nuF = nuG;
rhoF = rhoG;
Tp = 600;
Np = 1005;
lambda = 0.0256;
path = '../postProcessing/probes/0/T';
columns=3;
headerlines=5;
data = loaddata(path,columns,headerlines);
data=transpose(data);
[x,y]=size(data);
Tin_sim = data(:,2); % mean temp inlet temp [K]
Tout_sim = data(:,3); % mean temp outlet temp [K]
t_sim = data(:,1);
fprintf('final inlet temperature of sim = %f K\n',Tin_sim(length(Tin_sim)) )
fprintf('final outlet temperature of sim = %f K\n',Tout_sim(length(Tout_sim)) )
uF = U/alpha; % interstitial velocity [m/s]
ReP_sim = uF.*ones(length(t_sim),1)*dp/nuF; % ReynoldsNr based in dp
Pr = nuF*rhoF*cp/lambda;
qin_sim = U * A * rhoF * cp .* Tin_sim;
qout_sim = U * A * rhoF * cp .* Tout_sim;
q_sim = (qout_sim-qin_sim); % particle fluid heat flux [W] (out-in)
Tmean_sim = 0.5*(Tin_sim+Tout_sim); % mean temp of fluid
deltaT = Tp - Tmean_sim; % mean temp diff between partcles and fluid
h=q_sim./(Np*dp^2*pi*deltaT); % average particle-fluid heat transfer coeff [W/(m2*K)]
Nu_sim = h.*dp/lambda; % mean particle Nusselt nr
t_sim = data(:,1);
fprintf('q_sim = %f \n',q_sim(length(Nu_sim)))
fprintf('Nu_sim = %f \n',Nu_sim(length(Nu_sim)))
%===================
% Nusselt Equation
%===================
fprintf('\ncalc Nusselt eqn:\n')
%% following Li and Mason
n=3.5
if (ReP_sim(length(uF)) <200)
Nu_LiMason=2.*ones(length(uF),1)+0.6*alpha^n.*ReP_sim.^0.5.*Pr^0.33;
elseif (ReP_sim(length(uF)) <1500)
Nu_LiMason=2.*ones(length(uF),1)+0.5*alpha^n.*ReP_sim.^0.5*Pr^0.33 + 0.02*alpha^n.*ReP_sim.^0.8.*Pr^0.33;
else
Nu_LiMason=2.*ones(length(uF),1) +0.000045*alpha^n.*ReP_sim.^1.8;
end
fprintf('Nu_LiMason = %f \n',Nu_LiMason(length(Nu_LiMason)))
%====================================%
% plot data
%====================================%
figure(2)
plot(t_sim,Nu_LiMason,t_sim,Nu_sim)
title("Nusselt nr")
legend("analytical - ","simulation")
%print('cfdemSolverPisoScalar_NusseltNr.eps','-deps2')
print -color "cfdemSolverPisoScalar_Nusselt.eps"
replot;
figure(3)
plot(t_sim,Tin_sim,t_sim,Tout_sim)
title("inlet/outlet temperature")
legend("inlet","outlet")
%print('cfdemSolverPisoScalar_NusseltNr.eps','-deps2')
print -color "cfdemSolverPisoScalar_temperatures.eps"
replot;