Flow boiling heat transfer of R123/R134a mixture in a microchannel

Numerical investigations on flow boiling heat transfer of ammonia water binary solution (NH3/H2O) in a horizontal microchannel

“…And the mass flux (dominates convection) and heat flux (related to wall superheat) are the most important factors affecting the flow boiling heat transfer performance [43,51]. Furthermore, the inlet concentration of the more volatile component of a zeotropic mixture is one of the most distinctive parameters that differentiates flow boiling of zeotropic mixtures from pure fluids [7][8][9][10]. Therefore, as the numerical model was successfully validated in section 2.4, the effects of mass flux, inlet NH3 concentration and heating surface temperature on flow boiling heat transfer of NH3/H2O mixture in microchannels were comprehensively investigated and compared under a constant wall temperature boundary condition.…”

“…They discovered that the flow boiling HTC of zeotropic mixtures in mini-channels were typically lower than the original pure fluids in most conditions, but the mixtures could delay surface dry-outs at high heat fluxes and also increase the critical heat flux (CHF) values significantly compared with pure fluids. Azzolin et al [9] and In et al [10] noticed that flow boiling HTCs of R1234ze(E)/R32 mixture and R123/R134a mixtures in microchannels with diameters of 0.96 mm and 0.19 mm were smaller than those of corresponding pure fluids at most experimental conditions, respectively. Results showed that the zeotropic mixture had higher CHFs than pure R134a though smaller HTCs at most cases.…”

A review of boiling heat transfer characteristics in binary mixtures

“…a wider range of boiling temperature at a given pressure). In some applications, however, the operating pressure of pure fluids need to be adjusted accordingly to fulfil the desired phase change conditions [3]. Similarly, by adaptably tailoring the thermos-physical properties of multicomponent solutions, binary mixture heat transfer fluids can be used to reduce the thermodynamic irreversibility in counter-flow heat exchangers, resulting in an increase of heat exchanger efficiency [4].…”