| Combined heat and mass transfer processes that occur when water evaporates from a film and when a liquid desiccant is regenerated in an open-cycle system have been investigated. The experimental setup consists of a channel where either water, or a liquid desiccant solution, flows over a heated plate and a stream of air flows over the liquid film in a counterflow arrangement. A detailed analysis of the heat and mass transfer processes occurring in the channel was performed. A fiber-optic holographic interferometer was used to measure the local heat and mass transfer coefficients from the air-liquid interface, and a set of thermocouples and dewpoint hygrometer were used to measure the overall heat and mass transfer rates in the system.;In the mechanical method, 2 mm glass rods were used to disturb the liquid film flow which also disturbed the flow of the air stream. The local temperature and concentration distributions were calculated and used to evaluate the local Nusselt, Sherwood number and Lewis number. It was observed that average Nusselt number Nu;The major emphasis of this work was to determine methods to enhance heat and mass transfer rates from the liquid film. First, without utilizing any enhancement techniques, the local and overall transfer rates from the two liquid solutions, pure water and a 25% by weight lithium chloride solution, were determined. Then mechanical and combined mechanical and chemical methods for enhancing the heat and mass transfer rates were investigated. |
