The development and thermal analysis of a U-shaped pulsating tube operating in a rotating system of coordinates

Abstract

A novel idea of heat transfer enhancement using a U-shaped pulsating tube in a rotating system of coordinates is presented and studied in the paper. The analyzed case consists of a U-shaped tube that rotates around the axis of revolution which is perpendicular to the tube axis. Similar to the classical Pulsating Heat Pipe (PHP), it is composed of an evaporation section, located at the ends of the U-tube, and a condenser section located in a tube bend. In the curved section of the tube a liquid slug is surrounded by two vapor plugs. Assuming laminar flow and ideal gas law for the vapor, the governing equations for the pulsating flow in a rotating system of coordinates are derived and non-dimensionalized, finally solved numerically using an explicit scheme. The goal of the analysis was to investigate the influence of the angular velocity and non-dimensional parameters on the thermal performance of the described device. It was found that the centrifugal force generated by rotational motion positively affects the thermal conductivity by increasing the pulsation frequency and decreasing the amplitude of the liquid slug displacement. The proposed buoyancy enhancement method may lead to new solutions during the cooling processes for the moving machinery elements.