The safety issues are a major restriction on coal mining and growing efforts are being made in the search for solutions that will guarantee sustainable use of energy resources. Liquid carbon dioxide is attracting particular interest of coal fire-fighting due to the promising efficiency of cooling and asphyxia. Our objective is to develop a valid model to simulate the dispersion and thermal behaviors of liquid carbon dioxide under crushed coal condition and assessment of liquid carbon dioxide injection for coal fire-fighting. For this purpose, a numerical approach which requires an accurate state equation for calculating physical parameters of carbon dioxide, also accounts for appropriate description of energy transformation during the injection is presented. The validation of such a model against three experimental tests on temperature variation is proposed, and the model has proved capable of accurately predicting the heat and mass transfer process when liquid carbon dioxide is injected into crushed coal. Furthermore, the impact of nozzle diameter on the dispersion and thermal behaviors of liquid carbon dioxide is extensively investigated.