Heat and mass transfer during adiabatic fluid boiling in channels of contact exchangers

Abstract

Reducing mass and size characteristics of heat and mass exchangers requires intensifying the heat and mass transfer processes inside them. The authors propose improving the performance of adiabatic evaporators by placing a packing made of capillary-porous material into the working chamber behind the nozzle. This packing is designed as a system of parallel channels positioned at an angle to the axis ensuring a stable film formation.This article presents results of a physical experiment on the influence of regime and geometric characteristics of the contact exchanger and some of its elements on the heat and mass transfer intensity during film formation on the packing surface with capillary-porous coating under adiabatic boiling.The research technique used by the authors consists in determining the heat and mass transfer characteristics of the proposed exchanger design and comparing them with the characteristics of the design currently used in the industry.The analysis of the obtained results shows that using the capillary-porous packing in adiabatic evaporator units allows increasing vapor capacity by 18.5%.Analyzing the experimental data made it possible to obtain dependences that allow determining the heat transfer intensity on the channel surfaces of the packing covered with capillary-porous coating during adiabatic boiling of superheated liquid within a wide range of Reynolds numbers Re∗=0,02...4. The obtained dependences may help improve the existing techniques for calculating contact heat exchangers.