Effect of corrosion on boiling heat transfer characteristics of metal specimens with micro-structure surface

Abstract

BackgroundMany existing studies have shown that the use of suitable surface modification methods can enhance the boiling heat transfer effect of metal components, making it have a broad potential application prospect in the pressurized water reactor. However, for the weak alkaline environment of high temperature and high pressure in the reactor, little literature is reported on whether this enhanced effect can be maintained for a long time.PurposeThis study aims to explore the effect of corrosion on boiling heat transfer characteristics of metal specimens with micro-structure surface.MethodsFirst of all, three micro-structures of micro-groove, micro-porous and micro-columns were processed on the surface of stainless steel plate specimens by laser processing. Then the specimens were placed in the high-temperature and high-pressure environment simulating the actual reactor conditions to carry out corrosion experiments for up to 200 d. Finally, the pool boiling experiment and visualization study of the specimens before and after corrosion were carried out for comparison.ResultsThe results show that the surface critical heat flux (CHF) of the three micro-structured metal specimens increases and then decreases with the increase of corrosion time, among which the micro-pores specimens have the largest bubble generation rate at the beginning of nuclear boiling, and the micro-groove specimens have the highest CHF.ConclusionsThe influence law and mechanism of long-term corrosion in pressurized water reactor on the enhanced heat transfer effect of different micro-structure surfaces are partially revealed by this study.

Keywords

• corrosion
• surface modification
• boiling heat exchange
• micro-structure
• visualization