More cases of comparison between optimized tubes and smooth tubes are shown in Fig. 6. In order to show the result better, the horizontal coordinate is set as log10 (C0). When the constant fluid power consumption is set as different values (different coefficient C0), Fig. 6 shows the increase of the performance of heat transfer and flow resistance compared with smooth tube at Reynolds number of 200. Heat transfer is enhanced when fluid power consumption increases and the value can achieve up to 4.8. As the consumption of fluid power is stemmed from fluid viscosity dissipation and momentum change in the flow, the increase of fluid power consumption can bring about the change of both fluid viscosity dissipation and momentum change. In this paper, flow