Analysis of improved novel hollow fiber heat exchanger

Plastic heat exchangers have been of increasing interest for lower temperature applications because of their superior resistance to chemicals and fouling characteristics. However, the quite low thermal conductivity of polymer materials limits their widespread use and acceptance. The Polymeric Hollow Fiber Heat Exchangers (PHFHEs) with extremely large surface area overcome the constraint and have attracted more and more attention. In this study, we improve the heat transfer performance of the PHFHEs by optimizing their structure. The optimized way is to place the polypropylene net between the inlet and the outlet of the shell side. The hydrodynamics and heat transfer characteristics of the PHFHEs without net and with net were studied experimentally as well as numerically. The accuracy of the numerical model is demonstrated by the comparison with the experimental results. In this model, the heat transfer coefficient and the pressure drop, together with the velocity and temperature fields are obtained and presented to help analyzing the heat transfer characteristics of the PHFHEs without net and with net. It is found that at the same flow rate, the shell-side heat transfer coefficient per unit pressure drop of the PHFHEs with net is obviously higher than that without net, indicating the PHFHEs with net have their advantages over the ones without net. (C) 2014 Elsevier Ltd. All rights reserved.