Enhanced boiling heat transfer of water/salt mixtures in the restricted space of the compact tube bundle

In desalinization devices and some heat exchangers making use of low-qualit y heat energy, both the wall temperature and the heat flux of the heated tu bes are generally quite low, hence cannot cause boiling in flooded-type tub e bundle evaporators with a large tube spacing. But when the tube spacing i s quite small, incipient boiling can occur in the restricted space and resu lts in higher heat transfer than that in a falling-film evaporator or durin g pool boiling at the same heat flux. This study experimentally investigate s the effects of the tube spacing, the positions of tubes, and the salt-wat er concentration on bundle boiling heat transfer of salt water in the restr icted space of the compact tube bundle evaporator under atmospheric pressur e. The experimental results provide a restricted space boiling database for salt water in the compact tube bundle. Of particular importance is informa tion concerning the influences of the tube spacing of the tube bundle and t he concentration of salt water in desalination evaporators.