Hydrodynamics and heatmass trasfer in the contact heat utilizator of gas-droplet type
Scientific work is devoted to experimental research, aimed at improving the efficiency of contact heat and mass transfer units by increasing the interfacial surface of heat and mass transfer during the liquid spraying by centrifugal nozzles, implementation of which results in significant savings of material and energy resources.
Comprehensive experimental study of the characteristics of the liquid spraying torch (irri-gation density, expansion angle of nozzle torch, the average volume-surface diameter of liquid droplets) was done. The influence of input parameters to the relevant properties was shown and surface area of the sprayed liquid droplets was defined.
The limit temperature of water heating and its dependence on initial vapor content in which water is heated to the limit temperature depending on the initial vapor content and dry air output were experimentally set. The parametric borders of effective use of centrifugal mechanical nozzle without evaporation of heated liquid drops were defined.
Intensity of heat and mass transfer in the contact gas-droplet unit with centrifugal nozzle in terms of heat utilization of energy units’ exhaust gases was experimentally researched. The em-pirical dependences for calculating the average heat transfer and mass transfer coefficients relat-ing to the actual surface of the sprayed liquid droplets are obtained for the first time. The peculi-arities of transfer processes in the gas-droplet system were determined and generalized depend-ence for heat and mass transfer were received.
Based on experimental studies of spraying characteristics and heat and mass transfer pro-cesses at vapor condensation from vapor-gas mixture on the sprayed liquid droplets, the method of calculating the droplet contact utilization unit was developed.
Keywords: centrifugal nozzle, vapor-gas mixture, volume-surface diameter of droplets, volume fraction of water vapor, contact heat and mass transfer.