Local Heat Transfer Process for a Gas–Liquid System in a Wall Region of an Agitated Vessel Equipped with the System of CD6-RT Impellers

Abstract

The results of the experimental studies of local heat process for a gas–liquid system in the region of the cylindrical wall of an agitated vessel equipped with the system of CD 6–RT impellers are presented. A lower CD 6 impeller (Smith turbine) and upper RT impeller (Rushton turbine) were located on the common shaft in a baffled agitated vessel of inner diameter equal to 0.3 m. Liquid height in the agitated vessel was equal to 0.6 m. Newtonian liquids of different physical properties were used as a continuous phase. Air was dispersed in the liquid. Local heat transfer coefficients were measured using both thermal and electrochemical methods. In total, 2280 experimental points were obtained. Distributions of the heat transfer coefficients were described by means of eqs 12–17 and 18–23 as a function of the Re and Pr numbers, dimensionless axial coordinate z/H, and modified Frg number, separately, for turbulent and transitional ranges of the fluid flow in the agitated vessel. Equations 12–17 and 18–23, concerning both coalescing and noncoalescing gas–liquid systems, have no equivalent in the open literature.