Experimental investigation on the performance of circumferential corrugations helical tubes based on thermodynamic and economic analyses

Abstract

In this study, the impact of applying circumferential corrugations on the helical tubes is experimentally probed and frictional and thermal performance of the circumferentially corrugated helical tubes are studied. For this purpose, water flow rates at 2, 3, 4, 5, and 6 L/min with 25°C enter assumed helical tubes. These tubes are exposed to constant heat flux of 800 W, produced by heater wire evenly wrapped around them. Corrugations with three different pitches and heights of 6, 9, and 12 cm, and 0.8, 1, and 1.2 mm are considered, respectively. The results revealed that in comparison to smooth helical tube, the increment of the corrugation height at constant corrugation pitch and decrement of corrugation pitch at constant corrugation height improves the pressure drop to the maximum of 2.054 and 1.488 and also improves heat transfer coefficient to the maximum of 1.702 and 1.456 at Reynolds of 4687. Moreover, from the Benefit-Cost Ratio point of view, at Re = 2147 applying corrugation height of 1.2 mm at corrugation pitch of 6 cm is 1.27 times more economical than the smooth helical ones.