Abstract: To understand the effect factors of solid energetic material combustion in microcombustion, the effect of the dimensions and thickness of combustor and the thermal conductivity of its wall on the temperature distribution of wall and the heat loss of a microtube combustor during the burning of solid grain in the microtube combustor was studied by transient-state thermal analysis under ANSYS. Results show that the heat transfer of combustor's wall is the key factor for combustion stability in microtube combustor. With the reduction in the dimensions of combustor, the interaction of gas and wall is strengthened, and the heat loss is also increased, resulting in the instability or extinction of combustion. The simulation also indicates that the thermal conductivity of wall has the competing effect on the heat transfer of combustor's wall. The heat loss of wall and the heat transferred through the wall axially to the preheated zone decrease with the reduction in the heat conductivity of wall, however, the former makes greater contribution, which improves combustion stability. In addition, a thicker wall is beneficial to combustion stability in a certain extent.

Key words: thermology, microtube, combustion, wall, heat loss, stability, numerical simulation