CHARACTERISTICS OF FLOW REGIMES IN SPIRAL PACKED BEDS WITH SPHERES

Abstract

Packed beds are used in many fields such as heat exchangers, cooling systems, filtration, and reactors. Porous media can be used in order to enhance the heat transfer between the solid and the fluid, but it also creates higher pressure drops for the same flow rate. The flow regime significantly affects the heat transfer and pumping power of the fluid. It is known that when the channel is either curved or packed separately, the pressure drop increases. There are many studies on pressure drop and flow regimes in porous media or curvilinear channels. However, there are not many studies on pressure drop and flow regimes in a curvilinear packed bed. In this work, the pressure drops and flow regimes were determined when the channel is both curved and porous media. The packed beds were formed with two different radii of curvature, 71 and 171 mm in diameter, and were filled from steel balls with different particle diameters of 2.00, 2.38, and 3.17 mm. The pressure drop in these spiral packed beds was measured experimentally and flow regimes were determined for each test chamber and ball diameter. In each flow regime, permeabilities, Forchheimer coefficients, and the coefficients corresponding to Ergun constants were calculated. The effect of the curvature ratio was interpreted as the difference from the straight packed beds. Determining the flow regime ranges of curved packed beds can help to better interpret the heat transfer and pumping power of the fluid in these regimes.