Mathematical Model for Predicting the Heat Transfer Characteristics of a Helical-Coiled, Crimped, Spiral, Finned-Tube Heat Exchanger

Abstract

This paper is a continuation of the authors’ previous work. Theoretical and experimental studies of the heat transfer characteristics of a helical-coiled, crimped, spiral, finned-tube heat exchanger in dry surface conditions are presented. The test section is a helical-coiled, finned-tube heat exchanger. The coil unit is composed of four concentric helical-coiled tubes of different diameters. All tubes are constructed by bending straight copper tube into seven layers of helical coil. Aluminum crimped spiral fins, with an outer diameter of 28.25 mm and a thickness of 0.5 mm, are connected around the tube. Hot water is used as a working fluid for the tube side, while ambient air is used for the shell side. The test runs are done at air mass flow rates ranging between 0.04 and 0.13 kg/s. The water mass flow rates are between 0.2 and 0.4 kg/s. The water temperatures are between 40 and 50°C. A mathematical model is developed and the simulation results show reasonable agreement with the experimental data.