Experimental study of nucleate pool boiling heat transfer to ammonia–water–lithium bromide solution

Abstract

Visualization of bubble nucleation during nucleate pool boiling outside a vertical cylindrical heated surface was done for ammonia–water binary and ammonia–water–lithium bromide ternary mixture in order to obtain a descriptive behavior of the boiling which was directly compared with the measured heat transfer coefficient at low pressure of 4–8 bar and at low ammonia mass fraction of 0 < x NH 3 < 0.3 and at different heat flux. The lithium bromide concentration of the solution was chosen in the range of 10–50% of mass ratio of lithium bromide in pure water. The effect of concentrations, heat flux and pressure on boiling heat transfer coefficient was studied. Still images taken with high speed camera are used to demonstrate the increase in boiling heat transfer coefficient with the addition of lithium bromide salt to ammonia–water mixture. Further work is required to obtain quantitative information about bubble nucleation parameters.