Abstract
Ammonia vapor absorption has been investigated experimentally by allowing superheated ammonia vapor to flow into a test cell to be absorbed into stagnant pool of al11monia water mixtures of different ammonia initial mass fraction Ci. The temperatures in the liquid and vapor and pressure in the cell are measured during absorption to estimate mass diffusion flux, which has been estimated by two ways where the first one is the Tillner-Roth and Friend actual state equation, and the second one is the interface heat flux that has been estimated by inverse heat conduction solution. They show strong dependency upon Ci in that the mass diffusion flux decreases dramatically with increasing Ci. Absorption process has been visualized by Mach-Zehnder interferometer and the obtained fringes have been analyzed to get the concentration distribution together with that obtained by theoretical solution in which ammonia concentration at the interface changes with time. The obtained optical images allowed us to distinguish between two layers with different speeds of fringes propagation. The layer with fast fringe propagation represents pure thermal diffusion where mass does not penetrate it, while the layer with slow fringe propagation is characterized with a superposition of heat and mass diffusion where heat has a large effect at short times from starting the absorption and this effect gets smaller with the elapse of time.
