Experimental study on the tube-side thermal-hydraulic performance of spiral wound heat exchangers

In this paper, an industrial-scale experiment with ten testing heat exchangers is conducted to study the influences of structures and working conditions on the tube-side heat transfer and flow characteristics of spiral-wound heat exchangers. The experimental results show that, with the increase of the winding angle, the tube-side heat transfer coefficients increase because of the enhanced secondary flow and slightly larger velocity. The compactness of the whole heat exchanger changes with the variations of the layer and tube pitch. When layer pitch and tube pitch decrease, the flow channel in the shell side is narrowed down, which makes the overall heat transfer temperature difference decrease and finally results in deterioration of the heat transfer in the tube side. For the friction factors, they decrease when the winding angle decreases due to the different turbulence status and velocities in the tube. As a parameter of working condition, the tube-side inlet temperature has a slightly negative effect on the heat transfer. Based on the experimental data, the correlations of Nusselt number and friction factor are developed. Comparing the experimental data and the correlations, the average errors of the Nusselt number and friction factor are 8.04% and 6.28%, respectively.

Automated summary

The experimental results suggest that the tube-side heat transfer coefficient of spiral-wound heat exchangers increases with the winding angle, while the overall compactness is influenced by the layer and tube pitch. Friction factors are affected by winding angle and internal turbulence, and tube-side inlet temperature has a slightly negative effect on heat transfer. Correlations between Nusselt number and friction factor have been developed based on the data, with average errors of 8.04% and 6.28% respectively when compared to the experimental results.