Polymer structural effects in turbulent drag reduction
Polyacrylamide (PAM) and polyacrylic acid (PAA) of different molecular weights were synthesized and their drag-reduction properties studied in aqueous solution. A PAM sample was chemically modified in order to produce either ionic or nonionic forms by employing either hydrolysis or reaction with glyoxal, respectively. A PAA sample was partially neutralized to yield varying degrees of ionization. The incorporation of ionic groups in the PAM molecule enhanced the observed drag reduction in proportion to the ionic content. This finding can be ascribed mainly to molecular expansion resulting from the fixed charge repulsion in the molecule. In the case of the nonionic modification, the drag reduction was dependent upon reaction conditions. For example, the glyoxal modified PAM prepared with a short reaction time (20 min) at a lower reactant ratio (Gly/PAM = 1/2) was more effective than one prepared with a long reaction time (60 min) using a higher ratio of reactant (Gly/PAM = 1/1). It is believed that both the bulkiness and the hydrophilic nature of glyoxal side groups contributed to the enhanced drag reduction. A marked rhoH dependence was observed in the drag reduction of PAA.(22 refs.)
- Research Organization:
- US Navy
- OSTI ID:
- 5044473
- Journal Information:
- AIChE Symp. Ser.; (United States), Vol. 69:130
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of polymer conformation on turbulent drag reduction
Drag reduction in non-aqueous liquids
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
POLYMERS
CHEMICAL PROPERTIES
DRAG
MOLECULAR STRUCTURE
REACTION KINETICS
TURBULENT FLOW
FLUID FLOW
KINETICS
360402* - Polymers & Plastics- Structure & Phase Studies- (-1987)
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)