A COMPUTATIONAL STUDY ON MIXING BETWEEN GAS TURBINE EXHAUST GAS AND FRESH AIR IN A SUPPLEMENTAL-FIRED HEAT RECOVERY STEAM GENERATOR

摘要

A computational study is performed to evaluate the performance of a newly designed additional air duct installed in a horizontal type of supplemental-fired heat recovery steam generator (HRSG). Both velocity and oxygen distributions are investigated at the inlet plane of the duct burner installed in the middle of HRSG transition duct. Two important parameters, the swirl angle of gas turbine exhaust gas (GTEG) and the momentum ratio of additional air to GTEG, are chosen for the investigation of mixing two fluids. It has been found that a flow correction device is essential to provide a uniform gas flow distribution, and the oxygen distribution is getting better under the same swirl angle as the momentum ratio increases.