Further laboratory experiments on a stack of optimal exit velocity distribution

Abstract

Further laboratory experiments were performed to study the performance of a stack of new design, of which the exit velocity was optimally distributed to ensure a minimal ambient air entrainment. Comparisons were made between the stack of new design and a conventional stack, under identical plant and atmospheric conditions. Experiments in a neutral ambient fluid showed that at a cross-wind velocity of 15.5 and 7 miles h −1, the additional plume rise gained by the plume from the stack of new design was 2.5 and 5 stack dia. respectively. A higher additional plume rise was gained at a lower cross-wind velocity. Experiments in stably stratified atmosphere showed that the plume from the stack of new design gave a higher plume rise and diffused better into the upper atmospheric layer. An undesirable wake was observed at the top of the stack of new design. A low velocity air jacket surrounding the flue gases is suggested as a means to eliminate or reduce this wake.