Heat transfer to a falling power-law fluid film

Steady heat transfer to water and purely viscous non-Newtonian fluid films falling down a vertical tube, for the case of uniform wall heat flux thermal boundary condition, was measured experimentally. The power-law fluids studied were aqueous solutions of Carbopol at 250 and 500 ppm (by weight) concentration. The heat transfer to power-law fluid film was lower than the Newtonian prediction, at comparable Pr,. A new correlation is proposed for dimensionless heat transfer coefficient over a range of 500 less than or equal to Re-a less than or equal to 5400, 6 less than or equal to Pr-a less than or equal to 20, and 0.7 less than or equal to n less than or equal to 1. (C) 1999 Elsevier Science Inc. All rights reserved.