Drag surfactant solution

The concepts of boiling in micro-channels and comparison to conventional size channels are considered in Chap. 6. The mechanism of the onset of nucleate boiling is treated. Specific problems such as explosive boiling in parallel micro-channels, drag reduction and heat transfer in surfactant solutions are also considered. 

The average Nusselt number, Nu, is presented in Fig. 4.10a,b versus the shear Reynolds number, RCsh- This dependence is qualitatively similar to water behavior for all surfactant solutions used. At a given value of Reynolds number, RCsh, the Nusselt number, Nu, increases with an increase in the shear viscosity. As discussed in Chap. 3, the use of shear viscosity for the determination of drag reduction is not a good choice. The heat transfer results also illustrate the need for a more appropriate physical parameter. In particular. Fig. 4.10a shows different behavior of the Nusselt number for water and surfactants. Figure 4.10b shows the dependence of the Nusselt number on the Peclet number. The Nusselt numbers of all solutions are in agreement with heat transfer enhancement presented in Fig. 4.8. The data in Fig. 4.10b show... 

Mechanochemical and chemical reaction engineering aspects in the break down of turbulent drag reduction of cationic surfactant solutions... 

H. W. Bewersdorff and D. Ohlendorf. The behaviour of drag-reducing cationic surfactant solutions. Colloid Polymer Sci, 266(10) 941-953, October 1988. 

Fig. 8 Drag reduction vs. Reynolds number of a typical drag reducing cationic surfactant solution Ci7H35N(CH3)3Cl/3,4-Cl-benzoate (5 mM/12.5 mM).

Enhancing Heat Transfer Ability of Drag Reducing Surfactant Solutions in Heat Exchangers... 

Aguilar studied the relationship of HTR in DR solutions to the reduction in drag. He found that the ratio, HTR/DR, was greater than unity and relatively constant over a wide range of N q for both surfactants and high-polymer systems. A plot of the ratio for a number of surfactant solutions is shown in Fig. 15. He also showed that a slightly different ratio based on modified terms in the numerator and denominator... 

Drag reduction in turbulent flows of dilute high-polymer of surfactant solutions is a striking... 

Fontaine, A.A. Deutsch, S.T. Brungart, A. Petrie, H.L. Fenstermachker, M. Drag reduction by coupled systems microbubble injection with homogeneous polymer and surfactant solutions. Exp. Fluids 1999, 26, 397-403. 

Qi, Y. Littrell, K. Thiyagarajan, P. Talmon, Y. Lin, Z. Zakin, J.L. Small angle neutron scattering (SANS) study of shearing effects on drag reducing surfactant solutions. Manuscript in preparation. 

Qi, Y. Investigation of relationships among microstructure, rheology, drag reduction and heat transfer of drag reducing surfactant solutions. Ph.D. dissertation. The Ohio State University, Columbus, OH, 2002. 

Gasljevic, K. Matthys, E.F. Experimental investigation of thermal and hydrodynamic development regions for drag-reducing surfactant solutions. Trans. ASME 1997, 119, 80-88. 

Qi, Y. Kawaguchi, Y. Christensen, R.N. Zakin, J.L. Enhancing heat transfer ability of drag reducing surfactant solutions with static mixers and honeycombs. Int. J. Heat Mass Trans. 2003, 46, 5161-5173. 

Rheology of polymer and surfactant solutions Maximum drag reduction asymptotes Type A and B drag reduction Mean velocity profiles and limiting asymptotes Turbulence intensities and stress balance... 

Over the past 60 years, a great deal of applied and theoretical research has been carried out on both polymer and surfactant DRAs because of their potential useful applications and the influence of the additives on both turbulent structure and rheology. Important results include the identification of maximum drag reduction asymptotes (MDRAs) both Virk s MDRA for polymer solutions [Virk et al., 1970 see Eq. (2.5)] and Zakin et al. s MDRA for surfactant solutions [Zakin et al., 1996 see Eq. (2.6)], relating solution nanostructures and rheological properties to macroscopic DR phenomena hypotheses on the influence of DRAs on turbulent structures, mechanisms for turbulent drag reduction, developing heat transfer enhancement techniques, and so on. 

In aqueous solutions of surfactants at concentrations above the critical micelle concentration (CMC), the molecules self-assemble to form micelles, vesicles, or other colloidal aggregates. These may vary in size and shape depending on solution conditions. In addition to surfactant molecular structure, the effects of concentration, pH, other additives, cosolvents, temperature, and shear affect the nanostructure of the micelles. The presence of TLMs or cylindrical, rodlike, or wormlike micelles at concentrations > CMCii are generally believed to be necessary for surfactant solutions to be drag reducing [Zakin et al., 2007]. 

Zhang et al. [2005b] studied the effects of various percents of ethylene glycol in water (15,20, and 28%) on cationic surfactant solution properties. Using commercial cationics from Akzo Nobel (Ethoquad 012 and 013), they observed that the cosolvent reduced the upper temperature limit for drag reduction, maximum percent drag reduction, maximum critical wall shear stress, and relative shear viscosity. The formation of TLMs was hampered, but the addition of excess sodium salicylate promoted TLM... 

Aguilar, G., Gasljevic, K., and Matthys, E. R, Coupling between heat and momentum transfer mechanisms for drag-reducing polymer and surfactant solutions, J. Heat Transfer, 121, 796-... 

Bewersdorff, H.-W., Drag reduction in surfactant solutions, in Structure of Turbulence and Drag Reduction, Gyr, A., Ed., Springer-Verlag, Berlin, 1990, p. 293. 

Bewersdorff, H.-W., Rheology of drag reducing surfactant solutions, Proc. ASME Fluids Eng. Div., 237, 25-29 (1996). 

Gasljevic, K., An experimental investigation of drag reduction by surfactant solutions and of its implementation in hydronic systems (turbulent flow, heat transfer), Ph.D. dissertation, Department of Mechanical Engineering. University of Cahfomia at Santa Barbara, 1995. 

Horiuchi, T., Yoshii, T., Majima, T., Tamura, T., and Sugawara, H., Effect of alkyl chain length and number of 2-hydroxyethyl groups on drag reduction behaviors of quaternary ammonium salt-type cationic surfactant solutions, Nippon Kagaku Kaishi, 415-421 (2001b). 

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