Drag Reducing Effect of Surfactant Solution on a Piping System and its Application for Saving Energy Consumption

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The purpose of our project is to clarify the flow mechanism of surfactant solution, which exhibits drastic drag reduction in a piping system. 'lb achieve this purpose, we made the experimental apparatus containing a straight circular cross sectional pipe and the bend with the curvature ratio (bend curvature divided by inner radius of pipe) of four, and conducted the investigation of rheological characteristics, pressure measurement, and WV measurement. Finally, we fried to explain the drug reducing effect relating with those results. These would to be valuable for an innovation of the new drug reduction technique. The result of the rheological characteristics investigation showed that our examining surfactant solution (LSP-01M) could also become the shear induced state(SIS)that was common in many surfactant solutions. In the experiment using a straight pipe, the developing process of the boundary layer was clarified in the case of surfactant solution. We also showed that the maximum dr … More ug reduction ratio exceeded over 70%, and that drug reduction effect did not completely disappear in the case of weight concentration of 50 ppm when increasing Reynolds number. The velocity distribution in the wall coordinate system was also provided. Velocity measurement were carried out in detail, and it was hind that the Reynolds shear stress, which is correlation of axial and radial velocity fluctuations, were suppressed by malting the symmetric distribution of the probability density function against outward interaction and ejection, inward interaction and sweep, respectively. It was also found that the apparent viscosity slightly apart from the wall coincided with that of SIS, and there was the region with smaller apparent viscosity adjacent to the wall. We explained the reason of suppression of Reynolds shear stress, utilizing this gradient of apparent viscosity. In the experiment using the bend, it was found that the disturbance induced by the bend could not vanish easily in the case of strong drag reduction, and that the existence of two regions with high and low velocities lasted until they made strong shear. We also found that there was little disturbance in the outer part of the bend. Less