Effect of salt on boiling heat transfer of ammonia-water mixture

Abstract

Nucleate pool boiling heat transfer coefficients were determined experimentally for NH3–H2O, NH3–H2O–LiNO3 and NH3–H2O–LiBr mixtures. Both the salts were effective in increasing the heat transfer coefficient of NH3–H2O mixture. A concentration of 10 mass% of the salts in water, produced the greatest enhancement in heat transfer coefficient at all the range of pressure, heat flux and ammonia concentration studied in this investigation. The experiments indicated that ammonia concentration also has the impact on the augmentation of heat transfer coefficient in NH3–H2O binary mixture by the addition of salts. For the solution of ammonia mass fraction 0.30, high concentration of LiBr gives the highest heat transfer coefficient, for ammonia mass fraction of 0.25, high concentration of LiNO3 gives the maximum heat transfer coefficient, for ammonia mass fraction of 0.15, both the salts are equally effective in increasing the heat transfer coefficient.