A systematic experimental investigation of heat transfer in evaporating liquid film flowing along horizontal smooth and enhanced tubes under the action of gravity is performed. A new method for measuring the local temperature of the tube wall by thermocouples, which are movable in longitudinal and axial directions, has been developed. The method enables to determine local heat transfer coefficient in liquid films evaporating on surfaces of complex geometry at a condition on the wall q(velence)const. The effect of Reynolds number, fin pitch and fin diameter on heat transfer enhancement is studied. Horizontal tubes with the round cross fins for the evaporation of water and water-NaCl solution increase the average heat transfer coefficient up to 70percent compared with smooth tubes.
展开▼
