Influence of Steam-Side Oxide Scales on Heat Transfer of T92 Tube in Power Plants

The affection of oxide scales formed during exposure of Cr steels in steam environments on the service of components is discussed. Numerical model of T92 tube with oxide scales inside is built in this paper. The influence of steam-side oxide scales on heat transfer of T92 tube is analyzed quantificationally. The results indicate that average temperature of the substrate increases approximately linearly with the thickness of oxide scales. Then, the critical thickness of oxide scales leading to overheating of T92 tube is given and discussed, which shows that increasing the inner surface temperature and exterior surface heat flux will decrease the critical thickness of oxide scales. Finally, the slopes of average metal temperature -oxide scale thickness lines are obtained through curve fitting. The linear relationship between average temperature increment of tube wall and oxide scale thickness is illustrated and analyzed.