Problems with a non linear thermal convection block

Hi all,

I have developed my own speed dependent convection block. At the end of the message you can see the code.

I get the following error using this model in a very simple model:

Initial conditions solve failed to converge. ...Nonlinear solver: failed to converge, residual norm too large. ......Here is the set of components with unconverged equations:

The model works with the built-in simscape convection block, therefore I'm sure the code is wrong. The error can be fixed changing this statement

heat_tr_coeff=3.974*AirHeatTransfCoeff/DiscDiam*Re^0.55;

in

heat_tr_coeff=3.974*AirHeatTransfCoeff/DiscDiam*Re;

How could I fix it?

Thanks

Cheers

 % code

Pietro

component DiscBrakeLatConv < foundation.thermal.branch

parameters area = { 1e-4, 'm^2' }; % Area DiscDiam={1,'m'}; %Disc diameter AmbientTemp={300,'K'}; %Ambient temperature end parameters (Access=private) AirKinViscosity={19.32*10^-6,'(m^2)/(s)'}; AirHeatTransfCoeff={0.0294,'W/(m*K)' }; end

inputs w = {0, 'rad/s'}; % Ang rate : left end

function setup % Parameter range checking if area <= 0 pm_error('simscape:GreaterThanZero','Area') end

    if AmbientTemp <= 0
       pm_error('simscape:GreaterThanZero','Ambient Temperature')
    en
end
equations
      let
          Re=((w*(DiscDiam/2)^2)/AirKinViscosity);
          heat_tr_coeff=3.974*AirHeatTransfCoeff/DiscDiam*Re^0.55;
      in
         Q == area * 3.974*heat_tr_coeff* T;
      end
  end
end
  end%