A novel method for inlet duct geometry improvement of heat recovery steam generators

• To suggest geometry improvement of inlet duct of heat recovery steam generators in power plants.
• To conduct numerical simulation of fluid flow in inlet duct of heat recovery and its optimization.
• To apply the proposed method in a standard inlet duct of a 5 MW HRSG in power plant.

The geometry of inlet duct of HRSGs strongly affects flow uniformity and plays an important role in an increase in the efficiency of combined cycle power plants (CCPPs) where HRSG is the main component. Therefore, using some remedies to create a uniform flow distribution in HRSG inlet duct seems to be required in order to avoid reducing the effective surface temperature. In this research paper, part elimination and lattice search (PELS) method is presented to improve the inlet duct geometry. This is an innovative method which improves the inlet duct shape due to the amelioration of the flow quality. Uniformity of the velocity profile is considered at the exit section by quantifiable performance parameters of Root Mean Square (RMS). The RMS difference of local velocity from average velocity is used to evaluate the uniformity of the flow. To apply this method, a standard inlet duct of a 5 MW HRSG is considered and improvements for this case are addressed. The terms of uniform velocity and temperature distribution along the HRSG is numerically solved and explained. Finally, the results are reported in order to compare the standard inlet duct and the improved one. The comparison shows that the flow uniformity at the duct exit section in the modified model has been enhanced.