Experimental and Numerical Study of Heat Transfer Enhancement in a Shell and Tube Heat Exchanger using Helical Coiled Wire Inserts

Abstract

A B S T R A C TAn experimental work on heat transfer enhancement in a shell and tube heat exchanger by insertion of helical coiled wires into the tube bundle was conducted. Four different pitch sizes were used (4.8, 6.4, 8.0, 9.6) mm. The working fluid for both shell and tube sides of the exchanger was water. Flow arrangement used was parallel and laminar for both sides with a Reynolds number for the tube inside ranging (100-920). Variables were taken into account, including; convection heat transfer coefficient, number of heat transfer units, thermal effectiveness, and pressure drop. CFD analysis was done in order to validate the experimental results. The study results showed an increase in heat transfer coefficient on the tube side by 54% due to the use of 9.6 mm pitched inserts. Highest thermal effectiveness obtained was in the case of 9.6 mm pitch inserts. Pressure drop rose up to 260% due to inserts.

The Effects of Circular Inserts on the Thermal and Flow Characteristics in a Horizontal Pipe Exchanger: A Numerical Investigation

“…In this area, studies involve numerical and experimental methods and mostly employ a circular single tube or pipe as the test section through which lies an insert (which are also called swirl/vortex generator or turbulator) to create turbulent flow [5][6][7][8][9][10][11][12][13]. Inserted into the pipes or tubes as blades [14], rods [15,16], rings [17,18], tapes [8,19], strips [8,20] or coils [21,22], tube inserts enhance heat transfer by providing increased flow mixing and thus creating turbulent flow induced by longitudinal vortices. Among the parameters that affect the enhancement rate induced by the turbulators are their shapes, geometry, placement, spacing or pitch, flow attack angle, material, effective diameter, Reynolds number, and further modifications such as perforations, wings, etc.…”