INVESTIGATION OF HEAT TRANSFER AND PRESSURE DROP IN FLEXIBLE METAL HOSES WITH CORRUGATED SURFACES

In this study, we conducted a numerical investigation of heat transfer and pressure drop in annular corrugated and 1-, 2-, and 3-start spiral-corrugated flexible metal hoses. To validate the numerical results for pressure drop, we established an experimental set-up. The pressure drop results were verified through experimental data, while the numerical heat transfer results were validated against existing correlations in the literature. The results obtained using the corrugated flexible metal hoses were compared to those of a smooth tube, and all hoses along with the smooth tube were 1 meter long. The hydraulic diameters of the annular corrugated hose and the spiral corrugated hoses were 25 mm and 26.2 mm, respectively, with a corrugation depth of 3.2 mm for all hoses. Water, at an average temperature of 25 °C, was used as the fluid, with a constant surface temperature of 70 °C for the test tube. Analyses were conducted for Reynolds numbers ranging from 10000–50000. The results indicated that the fluid outlet temperature and pressure drop values for the annular corrugated hose were generally higher than those for the spiral corrugated hoses. Among the hoses tested, the 1-start spiral corrugated hose showed the highest friction factor, 7.83 times higher than that of the smooth tube. The 3-start spiral corrugated hose achieved the highest Nusselt number, 1.4 times higher than that of the smooth tube, at a Reynolds number of 20000. The performance evaluation criteria for all hoses ranged from 0.6–1.