The Hydraulic Institute (HI) has published a new American National Standard for Effects of Liquid Viscosity on Rotodynamic (Centrifugal and Vertical) Pump Performance (ANSI/HI 9.6.7). Replacing 40-plus-year-old HI viscosity correction nomographs, the Standard is designed to predict the performance change of rotodynamic pumps operated on viscous liquids exhibiting Newtonian behavior relative to their performance on water, which is the basis for most published curves.
"By eliminating the need for interpolating graphic solutions, this Standard has major technical significance and practical application," explained Gregg Romanyshyn, technical director for HI. "This landmark Standard will provide valuable guidance to pump manufacturers, users and others who have an interest in the performance of rotodynamic pumps."
HI members developed the new Standard in collaboration with representatives from France, Germany, Italy, Japan and Switzerland. The Standard includes contributions from an array of prominent industry experts and veterans.
A variety of rotodynamic pumps of conventional design are covered, including open or closed impellers and single or double suction pumps. In addition, the Standard includes information on methodology, definitions of symbols and terms, flowcharts that outline the procedure, theoretical explanations behind the methodology and a method for estimating net positive suction head required.