Optimization of an indirect heating process forfood fluids through the combined use of CFD andResponse Surface Methodology

The behavior of a counter-current tube-in-tube heat exchanger for fluid foods, was simulatedunder different operating conditions with a Computational Fluid Dynamics (CFD) parametricstudy. Three input parameters (product velocity vp,in, inlet product temperature Tp,inand inletwater temperature Tw,in) and two output parameters (outlet product temperature Tp,outandpressure drop across the heat exchanger p) were chosen. The results highlighted that therelative impact of vp,inon p was positive (93%), while higher Tp,inand Tw,inyielded lowerpressure drop values (−3% and −4%, respectively). Tp,outwas influenced positively by inletproduct (62%) and water (22%) temperatures, and negatively by vp,in(−16%).A Response Surface (RS) was then generated and validated with a suitable experimen-tal campaign. A good agreement was found between the simulated and the experimentalresults: Tp,outand p have been calculated with mean errors of 0.85 K and 628 Pa, respec-tively, thereby confirming the potential value of the RS as a Reduced Order Model, whichcould be used to develop a Digital Twin of the device. This modelling approach leads to asignificant state-of-the-art improvement, allowing m the results of the CFD simulations tobe ready-to-use, and granting deeper knowledge and finer control of the system.