Heat transfer in boiling of multicomponent mixtures

Abstract

Pool boiling data of multicomponent mixtures show that the heat transfer coefficients can be considerably lower than those of a corresponding pure fluid with the same physical properties as the mixture. The proposed model, which assumes maximum mass transfer resistance in the liquid boundary layer, is confirmed by the comparison between calculated and experimental data. The model allows the prediction of heat transfer coefficients in pool boiling of mixtures using only single component properties and vapour‐liquid equilibrium data. Judging by experience with a number of different systems, the method should be sufficiently accurate for most practical applications.

Pool Boiling Heat Transfer to Phosphoric Acid Solutions

“…As a consequence, there is back diffusion of the phosphoric acid away from the interface into the bulk liquid. Schlünder [5] and Schmitt [6] have shown that the vaporization process can be divided into two consecutive stages. In the first stage, nucleate boiling occurs with bubble growth at the heat transfer surface.…”

“…As a result, a concentration gradient will be set up across the diffusion shell, causing water molecules to diffuse toward and phosphoric acid away from the interface. The relationship between the local interface concentration of water, x i w , and the liquid bulk concentration, x b w , can be obtained from the Stefan-Maxwell equations in combination with the film theory ( [5,6]):…”