Experimental direct contact heat tranfser in upward air-water developing annular flow

Some experimental results are presented in order to quantify the impact of several operating parameters on the direct contact heat and mass transfer processes between hot water and cooling air, flowing upward inside a vertical, adiabatic, circular tube (12 mm i.d.), in the developing co-current annular flow regime. The proposed temperature measurement technique for the gas phase is based on the energy and mass balance equations applied to proper control volumes. The data processing method seems to be particularly suitable for the performance evaluation of the direct contact heat transfer occurring between the phases during the flow. Further developments are expected in the characterisation of different injection systems used for the mixing of two fluids in thermodynamic non-equilibrium conditions.