The experimental analysis of aqueous lithium bromide vertical falling film absorption

A heat and mass transfer test stand was fabricated and used to investigate non-isothermal falling film absorption of water vapor into a solution of aqueous lithium bromide. Experiments were conducted on an internally cooled smooth tube of about 0.019 m outside diameter and of 1.53 m length. The coolant temperature profile was measured along the running length of the absorber. The interface temperature of the falling film was measured with a new technique using thermographic phosphors. Information gleaned from the local measurements led to the development of a predictive algorithm. The algorithm was validated against the experimental data from this study and also from data published in the open literature. The algorithm predicts the absorber load and the mass absorbed within {dollar}pm{dollar}10 and {dollar}pm{dollar}14%, respectively.; The data, for testing at 0.62 and 0.64 mass fraction of LiBr, were scaled and correlated into both Nusselt and Sherwood formulations. The average absolute error in the Nusselt correlation is about {dollar}pm{dollar}3.5% of the Nu number reduced from the experimental data. The Sherwood correlation is about {dollar}pm{dollar}5% of the reduced Sh data. Data from the open literature were reduced to the author's Nu and Sh formulations, and were within 5% of the correlations developed in the present study.