Rheological Characteristics And Drag Reduction Effects Of Non-Newtonian Fluid In Wavy-walled Tubes For Steady Flow

Though people's living conditions have been improved significantly with the miraculous economic take-off, yet high pollution, high energy-consuming and high emission prove a curse upon human race. It is high time to promote construction of ecological civilization and advocate the theme of sustainable development. Improving energy efficiency plays an effective role on saving energy in many environmental projects. An increasing number of researchers devoted to the study of drag reduction effect of polymer solutions and make effective efforts to the development of society.Firstly, rheological characters of three different polymer solutions have been investigated in this paper:CMC solutions with low concentration 100?1000pm, medium concentration 1000?10000ppm and high concentration 10000?50000ppm, PAM solutions with low concentration 100-400ppm and 1000?10000ppm and Carbopol fluids with 2500-25000ppm. Then, drag reduction effects of CMC aqueous solution in two different sizes of sinusoidal wavy-walled tubes are investigated experimentally among medium Reynolds numbers. Besides, flow visualization experiments are conducted by the technology of PIV. Based on the experimental results, the following conclusions can be reached.The results indicate that viscosities of CMC and PAM solution with low concentrations do not distinctly vary with the shear rate and the shear thinning obviously can be seen until the concentrations achieve the medium level. In addition, the area of the Newtonian platform, existing among the low shear rate range for CMC solutions with high concentration, decreased with increasing concentration. In addition, distinct drag reduction effect exists in the laminar and transition flow region and the higher drag reduction can be arrived using 600-900ppm solutions which are the optimum concentration range. Furthermore, traditional region is advanced compared to the Newtonian fluid, the higher concentration the flow possesses, the earlier it reaches the traditional region. Lastly, the closer the fluid index of the polymer to Newtonian fluid reaches, the lesser drag reduction effect the fluid owns. Those results which this paper has discussed above are surely good for the research and development of drag reducer and the commercial process is bound to improve.