The effect of adding one of three salts (NaCl, $Na2SO4$ or $MgSO4)$ to water sprayed on a hot surface was studied experimentally. A copper test surface was heated to 240°C and quenched with a water spray. The variation of surface temperature during cooling was recorded, and the surface heat flux calculated from these measurements. Surface heat flux during cooling with pure water sprays was compared with that obtained using salt solutions. Dissolved NaCl or $Na2SO4$ increased nucleate boiling heat transfer, but had little effect on transition boiling during spray cooling. $MgSO4$ increased both nucleate and transition boiling heat flux. Enhanced nucleate boiling was attributed to foaming in the liquid film generated by the dissolved salts. $MgSO4$ produced the largest increase in nucleate boiling heat transfer, $Na2SO4$ somewhat less and NaCl the least. A concentration of 0.2 mol/l of $MgSO4$ produced the greatest heat flux enhancement; higher salt concentrations did not result in further improvements. During transition boiling particles of $MgSO4$ adhered to the heated surface, raising surface roughness and increasing heat transfer. Addition of $MgSO4$ reduced the time required to cool a hot surface from 240°C to 120°C by an order of magnitude.

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