1 Reply Latest reply on Mar 24, 2012 1:32 PM by David Paulson

    Heat exchanger - Which simplifications form CAD-model to the CFD Model

    Jose Manuel Lorenzo

      Hello everyone,


      I have a model of a heat exchanger to simulate in Flow. Of course, the geometry of this model is big to be done by Flow or any CFD I think,

      and some simplifications are required. What kind of the simplifications can I make? How can I simplified the tube bundle of the exchanger and not lost accuracy

      on my results?

      I see the tutorial of Flow Simulation regarding this kind of simulation but not mention how to get to that CFD model.




        • Re: Heat exchanger - Which simplifications form CAD-model to the CFD Model
          David Paulson



          I have simulated the heat exchange in shell and tube heat exchangers we design and heat exchangers that we buy from outside suppliers.  You are correct in your estimation of the difficulty in using Flow or any other CFD to analyze the exchange of heat in a heat exchanger with for example 100 tubes with two, four or more pass configurations.  And consider that the heat exchange tubes can also be enhanced on the exterior with "fins" to increase surface area and on the interior with spiral fluting to decrease laminar flow, the question becomes how manyweeks will be required to run the analysis instead of hours.


          What I have done is to perform the analysis on just one tube which may also be modeled to reflect 2/4/or more passes.  For prime surface tubes this analysis usually takes about 30 minutes.  However, if I use finned tubes the analysis will take about 40 hours.  At this point I decided that adding spiral fluting, or turbulators,  to the interior of the tubes might crash my system before results were even obtained. 


          Flow can be utilized for heat exchange if your model is very highly scaled.  However, you can get fluid flow (no heat analysis) analysis in a reasonable amount of time if the flow is inside the tubes and the inside of the tubes are not enhanced.