Functional Mockup Units and FEATool

Can i integrate a simulation generated within an FMU with FEATool

Could you clarify a little what you want to do and achieve, assuming with FMU that you're refering to a Functional Mock-up Interface Unit (https://fmi-standard.org)?

It seems you can import FMI units to Simulink (https://www.mathworks.com/help/simulink/ref_extras/fmu.html) a separate toolbox from the Mathworks, and also call Matlab m-file functions, such as those of FEATool, from a function block https://www.mathworks.com/help/simulink/slref/matlabfunction.html.

I have a thermal heat recovery system that includes a simple pipe network. I want to do a detailed simulation of the conduction within the heat recovery bed to access heating and cooling rates within the bed. For the system of multiphase flow tubes within the bed I'd like to model using a Modelica fluid network. I can create an FMI/FMU from the Modelica tool and would like to interface it to the 3D conduction FEATool calculation within the bed to get a full picture of the heating/cooling of the fluid over time.

Hard to say how well it could work. Either you would probably have to remake your Modelica model in Simulink, or as suggested earlier import it into Simulink via the function suggested earlier.

Another alternative might be to use the OMMatlab (OpenModelica Matlab Interface) to call Modelica from Matlab where you can also run FEATool models.