The contribution latent heat transport in subcooled nucleate boiling

Analysis is developed to determine the importance of latent heat transport in nucleate boiling heat transfer to a subcooled liquid. With the aid of experimental data in water for individual bubble radius vs time behaviour, the total amount of latent heat transported through the bubble during its lifetime is calculated, and this latent heat is significantly less than the measured heat transfer per bubble. It is concluded that microconvection is the important mechanism for the enhanced heat transfer observed in subcooled water. The results presented here apply only to highly subcooled liquids where bubble growth and collapse occurs at the heated surface, and not to boiling heat transfer in saturated or nearly saturated liquids. In the latter situation the very different bubble dynamics makes possible a significant contribution from latent heat transport. (author)