Session: 21-05 Operational Flexibility

Submission Number: 178719

Water Spray Cooling of a Radial Exhaust Hood at Low-Load Condition: Influence of Injection Parameters 

The increasing share of renewable energy sources in the energy market has changed how traditional fossil-fueled plants are operated. For steam plants, this means that steam turbines spend more time operating under low-load conditions, making component design even more challenging than before.

For example, exhaust casings are primarily designed to recover the kinetic energy at the exit of the last stage, thereby increasing the enthalpy drop across that stage and improving the overall efficiency of the machine.

However, when the steam turbines are operated under low-load conditions, these components exhibit poor aerodynamic performance and are subjected to significant thermal loads caused by the ventilation of the last stages.

Currently, water injection is the most effective method for cooling the exhaust casing walls and mitigating the impact of these thermal loads on the structural integrity of the component.

In this paper, various aspects of this cooling method are investigated. A computational setup suitable for this type of analysis is proposed, ensuring both physical consistency of the phenomenon and acceptable computational cost.

Finally, a sensitivity analysis of fluid dynamics and geometrical injection parameters is performed to evaluate their influence on cooling effectiveness and on the overall temperature distribution within the exhaust hood.

Presenting Author: Isacco Rafanelli University of Florence

Presenting Author Biography: Isacco Rafanelli received his Ph.D. in Mechanical Engineering from the University of Florence.
His research activities range from broad-spectrum multiphase modeling in steam turbines to the development of multiphysics models for the simulation of thermal transients during start-up and shutdown phases of turbomachinery.

Authors:

Isacco Rafanelli University of Florence
Antonio Andreini University of Florence
Lorenzo Arcangeli Baker Hughes, Turbomachinery and Process Solution
Sara Rizzi Baker Hughes, Turbomachinery and Process Solution
Nicola Maceli Baker Hughes, Turbomachinery and Process Solution
Tommaso Diurno Baker Hughes, Turbomachinery and Process Solution