% Heat conduction in pipe, heatp2.m (was heatr.m)
% 3-in pipe insulated with 0.5-in asbestos
% and 2-in glass wool

clear                       % variables
format short e              % E format

k12 = 2*pi*0.12/log(2/1.5);  % therm cond, length
k23 = 2*pi*0.032/log(4/2);   % therm cond, length
k22 = k12 + k23;
beta = k12*1e7               % zienk factor

stiff = [ k12   -k12     0   % stiffness matrix
         -k12    k22   -k23
           0    -k23    k23 ]
  df =  [ 400*beta;  0;  100*beta ];  % combined
zienk = stiff;
zienk(1,1)=zienk(1,1)+beta;
zienk(3,3)=zienk(3,3)+beta
format short
temp = inv(zienk) * df;    % displacements
heat = stiff * temp;       % force vector

% print the results
fprintf('\n    Heatr, Radial heat transfer, 3 materials ')
fprintf('\n      Your name, ES 421, ')
disp(date)

fprintf('\n   Node Temperature   Heat')
fprintf('\n              F      Btu/Hr\n')
for i = 1:length(df)
  fprintf('    %2.0f   %7.1f   %7.1f \n',i,temp(i),heat(i))
end

%    Heatr, Radial heat transfer, 3 materials
%      Your name, ES 421, 21-Mar-2001

%   Node Temperature   Heat
%              F      Btu/Hr
%     1     400.0      78.3
%     2     370.1      -0.0
%     3     100.0     -78.3