Effect of Helix Amplitude and Helix Pitch on the Performance of a Swirl Flow Tube

In the author’s another study, the effect of helix length on the performance of a swirl flow tube (SFT) was investigated. In this study, The heat transfer enhancement and the pressure drop were investigated using CFD to obtain an optimal compromise between the temperature uniformity and the pressure drop gain. It was found that a helix length of 40d is an optimal compromise between the temperature uniformity and the pressure drop gain. In this paper, another two important parameters regarding the operation of an SFT, the helix amplitude and the helix pitch are investigated to get a more thorough understanding of the SFT performance. The pressure decreases to a larger extent for a larger helix amplitude and the pressure drop is nearly proportional to the helix amplitude. In addition, the temperature increases with the helix amplitude, and the improvement in temperature uniformity index enhances with increasing helix amplitude. Concerning the influence of the helix pitch, the pressure decreases to a larger extent for a smaller helix pitch and the pressure drop is nearly inversely proportional to the helix pitch. The temperature decreases with the helix pitch and the improvement in temperature uniformity index are enhanced by decreasing the helix pitch.