A three-dimensional flow of a low-density polyethylene in a spiral-mandrel die for a blown-film extrusion is simulated. The effect of elongational viscosity on the flow in the spiral-mandrel die is analyzed. Elongational viscosity is found to have only a minor effect on the velocity distribution, but a significant effect on the pressure and temperature distributions in the die. (c) 2006 Wiley Periodicals, Inc.