Abstract:
In order to study the heat transfer characteristics of bituminous coal under the condition of variable oxygen volume fraction, the long-flame coal, medium-clay coal and gas-fat coal were used. Three kinds of coal samples were used as the research objects. The LFA457 laser thermal conductivity meter was used to measure the thermal diffusivity, specific heat capacity and thermal conductivity of the coal samples. And the coal samples were studied in three different oxygen concentrations(5%, 13%, 21%). The coal samples were heated from room temperature to 300 ℃ under three different oxygen volume fractions, and the changes in thermal physical parameters of coal from 30 - 300 ℃ were detected. By analyzing the heat conduction characteristics under different oxygen volume fraction conditions, with the increase of oxygen volume fraction, the critical temperature of the thermal diffusivity steadily moved into the low temperature area. When the temperature rises over the critical temperature, the specific heat capacity at the same temperature decreases as oxygen volume fraction rises, whereas the change in thermal conductivity is determined by thermal diffusivity. The analysis of temperature sensitivity reveals that the effect of oxygen volume fraction on the thermal property parameters is small before the temperature reaches the critical temperature; while the effect of oxygen volume fraction starts to become larger after the temperature exceeds the critical temperature.