陶瓷热障涂层的隔热效果研究

THERMAL BARRIER EFFECT OF CERAMIC THERMAL BARRIER COATINGS

通过理论公式推导和试验测量 ,得出 :热障涂层的隔热效果与环境温差成正比 ,但同等环境温差下涂层在更高的温度工作时 ,由于涂层材料导热系数的增大 ,其隔热效果减小。涂层厚度与隔热效果在实际涂层应用的厚度范围内也接近线性关系。随着发动机叶片冷却气流换热系数增大 ,热障涂层的隔热效果也越大 ,但两者并不是线性关系。涂层隔热效果随导热系数的减小而增大 ,并且在低导热系数区 ,热障涂层隔热效果对导热系数的变化更敏感。随着涂层的厚度增大 ,导热系数的改变所具有的增加涂层隔热效果的作用越大 ;但涂层越厚 。

Experimental and theoretical analysis shows that the thermal barrier effect having a near linear relation to the ceramic coating thickness is proportional to environment temperature difference. As the heat exchange coefficient of the cooling gas increases, the changes in the thickness of ceramic coating will be more efficient in terms of the thermal barrier effect, which increases with the decrease of the thermal conductive coefficient of ceramic coating. In the low thermal conductive coefficient zone this effect is more sensitive to the thermal conductive coefficient. On the other hand, lowing thermal conductivity will bring less thermal barrier effect as the ceramic coating getting thicker.