Effect of Molar Ratio of Sodium Salicylate/Bis (2-hydroxyethyl) methyl (cis-9-octadecenyl) ammonium Chloride on Drag Reduction Behaviors
Teruo HORIUCHI*, Toshiaki MAJIMA, Toru YOSHII and Takamitsu TAMURA
Material Science Research Center, Lion Corporation; 13-12, Hirai 7-Chome, Edogawa-ku, Tokyo 132-0035 Japan
In order to elucidate the mechanism of Drag Reduction (DR) effect in a turbulent pipe flow, properties of aggregates in NaSal/HMODA solutions were measured under shear by means of flow birefringence and rheometry. DR effect appeared when the molar ratio of NaSal/HMODA was above 0.5. As the molar ratio was further increasing, it tends to have good drag reducing abilities up to higher Reynolds number. To ascertain the formation of structural association under shear, the first normal stress difference (N1) for various molar ratio of NaSal/HMODA was measured as a function of shear rate. The N1 for HMODA solution without NaSal decreased as the shear rate increased. This is characteristic for a Newtonian fluid. However, when the molar ratio of NaSal/HMODA increased to above 0.5, the values for N1 first increased slowly up to about shear rate of 500 s−1, after which they settled down to a plateau. It is suggested that they underwent structural associations which were due to the formation of shear-induced structure (SIS) when a critical value of the shear rate was exceeded. Based on these results, it was found that the formation of SIS played an important role in DR effect.
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