| The pool boiling behavior of nineteen combinations of polymer-surfactant aqueous solutions has been investigated under atmospheric pressure conditions. An electrically heated horizontal platinum wire, 0.0254 cm, served as the heating test section in the saturated liquid pool. The polymer selected was an anionic polyacrylamide, Separan AP-30. The surfactants used in these studies were the anionic sodium lauryl sulfate (SLS) and the non-ionic polyoxyethylene sorbitan monooleate (Tween-80). Deionized water served as the solvent for all solutions.;The boiling process resulted in a reduction in the apparent viscosity and fluid elasticity. However, the surface tension values were not markedly affected by the boiling process.;The boiling performance of SLS and Tween-80 aqueous solutions, with significant lower surface tension values than water, did not differ from the performance found for water alone. The presence of either surfactant in Separan solutions indeed improved the heat transfer coefficients at a fixed heat flux relative to those found in Separan solutions which exhibited the worst performance.;However, relative to the pool boiling performance of water, the AP30-SLS aqueous solutions show enhanced heat transfer at constant heat flux values above 20 W/cm2, whereas the AP30/Tween-80 showed no improvement.;The values of the apparent viscosity and the elasticity are dominated by the amount of polymer additive, whereas the values of the surface tension are dominated by the surfactant concentration. The presence of surfactants generally decreases the elasticity found for polyacrylamide solutions.;The bubble behavior in deionized water, 1000 wppm SLS solution, 500 wppm AP-30 with 1000 wppm SLS solution and 500 wppm AP-30 with 500 wppm Tween-80 solution was also investigated. The bubble departure diameter, the bubble emissive frequency, and the bubble density were correlated as functions of heat fluxes for each solution. Of all solutions studied the Separan-SLS solution exhibited the smallest bubble diameter at departure, the highest bubble emissive frequency and the largest bubble nucleation site density. |
