Numerical investigation of heat transfer characteristics of spiral, helical, and conical tubes

Abstract

A tube type heat exchanger is generally used in many industrial applications due to its high heat exchange property and compact structure. Due to the formation of turbulence in a curved section of pipe dean vortices are formed which leads to an increase in heat transfer coefficient. Heat transfer characteristics such as heat transfer coefficient and heat rate for spiral, helical and conical tubes are studied by using ANSYS Fluent. Additionally, pressure drop, temperature distribution, and velocity distribution are also shown for three different tubes. The outlet temperature of fluid flowing through tubes is predicted using a steady-state numerical simulation utilizing a Fluent solver. Similar tube diameter and length are considered for all CFD trials. The outlet temperature of heat transfer fluid is varied with the mass flow rate for all shapes of tubes. A maximum outlet temperature of 338.39 K is observed for the spiral tube for a 0.04 kg/s mass flow rate. For a 0.04 kg/s mass flow rate, the heat transfer coefficient of a spiral tube is 0.44 percent higher than that of a helical tube and 2.57 percent higher than that of a conical tube. Additionally, pressure drop through the spiral tube is 2 % greater than the helical and conical tube.