AN EXPERIMENTAL-STUDY FOR PREDICTING CIRCULATION RATES IN A REBOILER TUBE

An experimental investigation of heat transfer to boiling liquids under natural convective flow through a vertical tube thermosiphon reboiler has been carried out to study the effect of heat flux and liquid submergence on circulation rates. Three.test liquids namely: water, methanol and ethylene glycol were used to cover a wide range of boiling points and thermophysical properties. The test section was an electrically heated stainless steel tube 25.56 mm i.d. and 1900 mm length. The uniform heat fluxes in the range of 4.1 to 43 kW/m2 were employed while inlet liquid subcooling varied from 0.5 to 11.6-degrees-C. The liquid submergence levels were maintained around 100, 75, 50 and 30%. Circulation rates for all test liquids have been correlated in terms of dimensionless groups.