热障涂层隔热机理分析及有效性判据

A one-dimensional convection-thermal conductivity model was established, and the thermal insulation effectiveness criterion of the thermal barrier coating was obtained through theoretical deduction and analysis. When the thermal resistance of the coating was greater than the heat transfer resistance of the high-temperature gas side without coating, the coating could generate a positive thermal insulation effect. On the contrary, the heat transfer coefficient for the external gas side after spraying the thermal barrier coating (TBC) had a maximum critical value. At this time, only when the external gas side heat transfer coefficient was smaller than this critical value after the TBC was sprayed, the TBC could have a thermal insulation effect, otherwise the thermal barrier coating couldn't work, even worsen the heat transfer of the blades. The temperature-drop of the TBC itself was proportional to the temperature-drop of the outer surface of metal blade with or without TBC. And a new evaluation standard of the thermal insulation effect of the coating based on the outer surface temperature of the blade metal substrate was proposed.