ON THE DEVELOPMENT OF LATTICE BOLTZMANN MODELING FOR LIQUID-SOLID PHASE TRANSITIONS IN FREE SURFACE FLOWS

Motivated by the current lack of knowledge regarding phase transition in a free surface water flow, a novel and efficient numerical model for liquid-solid phase transition in a free surface flow has been developed for the Lattice Boltzmann Method (LBM). The proposed model consists of two physically sound modules for solving free surface flow and heat transport. The heat transport module features an immersed boundary method and a non-iterative enthalpy-based approach. Sub-cycling time integration, improving the numerical stability of the heat transport module, is introduced for the integration of modules. The performance and accuracy of the model are verified through a preliminary experiment involving a melting ice cube. The obtained results indicate that the phase transition of fluid in any flow regime can be easily handled by the model with reasonable accuracy

STEAM GASIFICATION OF SOME MONGOLIAN COALS

The gasification tests for the Alagtolgoi and Ailbayan coal deposits were conducted in the temperature up to 850°C using bench scale reactor in order to evaluate product gas composition. Prior to the gasification experiments, the raw coal was pyrolysed in a stainless steel reactor under N2 atmosphere at a temperature of 500°C for 1 h. General behavior of the coal conversion was quite similar for both coals. The gasification tests show that an increase in temperature enhances the formation of hydrogen, carbon dioxide and carbon monoxide. The highest yield of hydrogen and carbon dioxide concentrations of the Ailbayan coal are achieved at temperature of 850°C, which were 2.859 mmol⋅g-1⋅min-1 and 1.054 mmol⋅g-1⋅min-1 respectively. However maximum rate of hydrogen for Alagtolgoi subbituminous coal reached around 800°C. Overall results show that the maximum gasification rate is reached earlier for subbituminous coal than for bituminous coal, but product gas evolution was higher for the investigated bituminous coal

ON THE DEVELOPMENT OF <em>LATTICE BOLTZMANN MODELING</em> FOR LIQUID-SOLID PHASE TRANSITIONS IN FREE SURFACE FLOWS

Motivated by the current lack of knowledge regarding phase transition in a free surface water flow, a novel and efficient numerical model for liquid-solid phase transition in a free surface flow has been developed for the Lattice Boltzmann Method (LBM). The proposed model consists of two physically sound modules for solving free surface flow and heat transport. The heat transport module features an immersed boundary method and a non-iterative enthalpy-based approach. Sub-cycling time integration, improving the numerical stability of the heat transport module, is introduced for the integration of modules. The performance and accuracy of the model are verified through a preliminary experiment involving a melting ice cube. The obtained results indicate that the phase transition of fluid in any flow regime can be easily handled by the model with reasonable accuracy.</p