2016 Volume 44 Issue 4 Pages 205-210
A photoreactive fluid is fascinating in a wide range of technological applications because of holding the promise of contactless flow control. The drag-reducing (DR) effects of photorheological fluids composed of nonionic surfactant [oleyldimethylamineoxide (ODMAO)] and photoreactive additives [ortho-methoxycinnamic acid (OMCA)] were investigated by measuring the pressure drop and flow rate in pipe flows. The concentration of ODMAO solution was 500 ppm by weight, the solution temperature was 20 ºC, and the molar ratio of trans-OMCA to ODMAO was varied from 0.2 to 1.0. The time variation of DR effects of photorheological fluids due to the UV irradiation was most obviously observed at the molar ratio of 0.8, which might be caused by the photoisomerization from trans-OMCA to cis-OMCA and corresponded to the variation of the shear viscosity.
