Investigation of Rope Formation in Gas-Solid Flows using Flow Visualization and CFD Simulations

Abstract

Investigation of Rope Formation in Gas-Solid Flows using Flow Visualization and CFD Simulations Venkata Subba Sai Satish Guda Coal is still one of the widely-used resources for power generation all over the world. Most of the relevant industries use pulverized coal as fuel which is delivered to the furnace by pneumatic conveying. Extensive use of coal has resulted in severe environmental problems due to emissions such as Carbon dioxide, Nitrogen and Sulphur compounds among others. It is postulated that if combustion efficiency is improved, this will lead to significant reduction in pollutant emissions. Combustion efficiency of pulverized coal power plants is influenced strongly by particle size distribution. Most industries use Cyclone Separators (or Classifiers) to separate the larger particles from the smaller ones as part of pre-combustion processes. The sizing and scaling of these classifiers are mostly based on empirical formulations. Detailed 3D numerical studies of these classifiers have not been successful in prediction of experimental observations, hence as such cannot be used as reliable tools for scale up studies. The main reason for this anomaly is believed to be failure of the models in capturing the dynamics of particle behavior in bends and ducts where particles form rope like structures with dense particle clusters. It is then imperative that more study is needed into the understanding of rope or cluster formation in gas-solid flows. My heartfelt thanks and salutations to my grandfather Dr. K. Sivananda Murthy garu for directing me, guiding me and making me achieve my PhD goal. He has always provided solutions to all the problems in such a manner that the problem never existed or reappeared later. Without him, this goal of PhD would have always remained a dream. Of course there is no question of him not being there for me. This degree is dedicated to him.