MODELING OF HEAT-RECOVERY STEAM-GENERATOR PERFORMANCE

The performance of the heat recovery steam generator (HRSG) strongly a ffects the overall performance of a combined-cycle power plant. An acc urate simulation of the performance of the HRSG is therefore necessary to analyze the effects of various design and operating parameters on the performance of combined-cycle power plants. Unfortunately, there a re many sources of uncertainty and operational variance which prevent the accurate prediction of the HRSG performance. Furthermore, the pred iction of heat-exchanger performance is based on assumptions about flo w patterns. Empirical correction for departures from these assumptions is not possible in cases where the benefits of new geometrical config urations are to be explored. A numerical method was developed to predi ct the performance of the HRSG in a fashion that accounts, as much as possible, for the design and operation constraints, while keeping comp utational complexity manageable. The method is intended for use in per formance-simulation models of advanced power cycles, since its accurac y is acceptable without requiring large computational resources. The m ethod was used to simulate the pressure, temperature, steam quality an d heat-flux distributions in a commercially available HRSG (operating under full- and part-load conditions). The predicted results were foun d to compare well with measurements obtained on full-scale units. (C) 1997 Elsevier Science Ltd.