Study On The Working Characteristics And Heat Transfer Enhancement Of The Polypropylene Self-Rotating Twisted Tapes Inside Vertical Heat Exchanger Tube

The self-rotating twisted tapes can not only remove fouling on line, but also enhance heat transfer. The resistance characteristics, rotating characteristics and heat transfer enhancement performance of self-rotating twisted tapes inserted vertical tube were studied base on abundant experiments. So this paper is also carried out from the former three points.Firstly, compare pressure loss of hollow tube and inserted self-rotating tapes tube, and then the equations of pressure loss increment and friction resistance coefficient about tape structure parameters were fitted through nonlinear fitting. Therefore the effect factors of them could be analyzed.Secondly, the moment of impetus and resistance were concluded. According to moment equilibrium, the equation of theoretical rotational speed was inferred, which was complied with the experiment data. Then the effect factors of rotational speed were analyzed. The results indicate that the main effect factors of rotational speed are fluid flow velocity and the pitch of tapes.Lastly, the total heat transfer coefficients K were calculated by applying to traditional heat transfer equations. The contrast of results show that the values of K are improved apparently when the self-rotating twisted tapes are inserted in tube at the same Reynolds number. Then the coefficients of heat-transfer and heat transfer equation were concluded by applying to the method of Wilson graphic solution. Further, the ability of heat transfer enhancement was assessed. The result indicates that the value of assessment factor for heat transfer enhancement is not only higher than 1, but also higher than aluminum twisted tape's at the same specifications.