Effects of extended surface and surface gold plating on condensation characteristics of steam with large amount of CO2

To promote steam condensation with high concentration of non-condensable gas, vapor mixture with 45-95% CO2 is adopted to experimentally investigate the effects of extended surface and surface gold plating on the heat-transfer enhancement. The results show that a gold-plated stainless vertical surface does not exhibit superior performance under the influence of less condensate and slower update frequency of the drops. A V-shaped fluted surface can enhance heat transfer under CO2 concentrations of 85% and 95%, but no further enhancement is shown after the gold-plating treatment on the surface. Although droplets formed at both the inclined surfaces and bottom of the groove, the disturbance of the droplet movement on the gas boundary layer is much weaker due to the lower heat flux. Both experimental results indicate that a proper increase in the fin spacing and height can improve the heat-transfer process on both untreated and gold-plated fluted surfaces.