Seminar: Faxén Seminars

Transonic Flow Features in a Nozzle Guide Vane Passage - towards entropy noise assessment

Speaker: Alessandro  Ceci
Organization: KTH
Time: 2017-06-21 13:00
Place: Teknikringen 8


The combustion noise in aero-engines is known to originate from two different sources. First, the unsteady heat release in the combustion chamber generates the direct combustion noise. Second, hot and cold spots of air generated by the combustion process are convected and accelerated by the turbine stages and give rise to the so-called indirect combustion noise. The present work offers a numerical investigation regarding the generation mechanism of indirect combustion noise for a simplified geometry of a turbine stator passage. Periodic temperature fluctuations are imposed at the inlet permitting to simulate hot and cold packets of air coming from the unsteady combustion. Three-dimensional LES are conducted for transonic operating conditions to evaluate the blade acoustic response and peculiar flow features. In fact transonic conditions are characterized by trailing edge expansion waves and shocks: their movement can be excited if disturbances with a particular frequency are injected in the domain.