On heat transfer enhancement by oscillatory rotating twisted tubes

Advanced Computational Fluid Dynamics (CFD) is developed by employing dynamic mesh motion and local mesh refinement techniques. This is to investigate, for the first time, the heat transfer enhancement by using elastically oscillating twisted tube rotating between −180° and + 180 ° . Under a laminar flow regime and for different operating rotational speed frequencies, it is shown that the local dynamic twisting deformation of the tube walls can significantly alter the internal flow behavior, thus efficiently enhancing the overall heat transfer; e.g., a case study applied to a square cross-section tube. At an oscillating frequency of f = 0.5 Hz , it is demonstrated how the thermofluid performance evaluation criterion (PEC) can increase up to PEC = 1.27 compared to the case of PEC = 1 at f = 0 which corresponds to a straight tube without rotary twisting oscillation. For the first time, it is shown how an elastic square-cross-section tube with a twisting oscillatory rotation can be a very promising technique for developing new technology and future generations of advanced heat exchangers.