6 - Inlets, Exhausts, and Noise Suppression

Abstract

The inlet to a gas turbine is designed to promote optimum air swallowing capability. Smooth geometry is essential, so its surface contour generally is kept as simple as possible. Its smooth surface may conceal pressure probes and heating boots that are part of an anti-icing system. The main aspects of the gas turbine inlet system, depending on where it is located and its application, include inlet filtration, inlet cooling and fogging, and inlet cooling. Furthermore, the gas turbine's exhaust system conducts the products of combustion, any unburned fuel, excess air, and the heat carried by all these gases away from the turbine. In contemporary land-based applications, energy conservation policies, environmental law, and growing awareness of the exhaust steam's potential resulted in a variety of energy conservation designs that are added to the tail end of the exhaust system. These include mainly waste heat steam generation for boilers, for civilian population's heating needs, and for greenhouses that grow vegetables and flowers. Finally, in all gas turbine applications, the noise one produces is a function of both its aerodynamic design (gas velocity and so forth) and its overall system, which includes its potential for resonance and additional vibration that would not be noted during test cell runs. By far the most demanding application for noise mitigation is with aircraft gas turbines.