Shell-and-tube polymeric hollow fiber heat exchangers with parallel and crossed fibers

Abstract

In this work shell-and-tube type polymeric hollow fibers heat exchangers (PHFHE) are described and investigated. These heat exchangers utilize polymeric microchannels with outer diameter of 0.8 mm as the heat transfer surface. Heat exchangers are made of hundreds of such fibers, which are situated in the heat exchanger shell. The main purpose of this work was to conduct a comparative study of two PHFHE: the first one had parallel hollow fibers inside the shell; the second one is a new type of PHFHE having cross-wound structure where hollow fibers were placed at an angle to the heat exchanger axis. Due to the new developed method of separation hollow fibers inside the shell – cross-wound method it was possible to create an arranged structure of hollow fibers. Experimental results has shown that the overall heat transfer coefficient for PHFHE with cross-wound hollow fibers was about 6 times higher than for PHFHE with a parallel fibers at the same average shell water flow velocity. For a shell water velocity of 0.08 m/s the overall heat transfer coefficient for cross-wound PHFHE was equal to 1170 W/m2K at a water temperature inside hollow fiber of 11 °C and a shell water temperature of 70 °C.