Determination of thermal state and modification of the flame tube cooling system with the help of three-dimensional modeling methods

The results of calculating the thermal state of the flame tube walls are presented, a gas turbine engine annular combustor taken as an example. The three-dimensional Ansys Fluent simulation package is used. A finite element conjugate model is created. The conformal (node-to-node) interface «gas-to-metal» is a characteristic feature of the grid. The number of elements over the thickness of the wall is taken to be not less than 5. The total number of elements is 8.6 million. The HN50VMTYUB-VI heat-resistant alloy is used as the material of the flame tube. A thermal barrier coating (TBC) is deposited on the hot side of the flame tube. The thickness of the ceramic coating is assumed to be equal to 0.4 mm. The thermal barrier coating consists of an intermetallic bonding layer that contains elements of the wall material of the flame tube and ceramics, as well as a ceramic protective layer with low thermal conductivity. The shell surface of the flame tube walls is assigned to take into account the thermal barrier coating. The density of the ceramic coating is 6 t/m³, and the dependence of the isobaric heat capacity of the thermal barrier coating on the temperature in the range of 473 K to 1473 K is specified.  The distribution of the heat flux in the thermal barrier coating is taken into account only in the direction perpendicular to the surface of the flame tube. The influence of the thermal barrier coating on the flame tube thermal condition is analyzed. Measures have been taken to improve the cooling system of the flame tube. Variations of the temperature of the flame tube along its length are analyzed.