Gazi I. Mahmood

Flow Dynamics and Film Cooling Effectiveness on a Non-Axisymmetric Contour Endwall in a Two-Dimensional Cascade Passage

The measured flow field and temperature field near a three-dimensional asymmetric contour endwall employed in a linear blade cascade are presented with and without film-cooling flow on the endwall. Flow field temperature and Nusselt number distributions along the asymmetric endwall with wall heating and no film-cooling flow are also reported to show local high heat transfer region on the endwall and justify the locations of the coolant holes. Adiabatic film-cooling effectiveness along the endwall is then measured to indicate the local effects of the coolant jets. The near endwall flow field and temperature field provide the coolant flow behavior and the interaction of coolant jets with the boundary layer flow. Thus, the local film-cooling effectiveness can be explained with the coolant jet trajectories. The measurements are obtained at the Reynolds number of 2.30×105 based on blade actual chord and inlet velocity, coolant-to-free stream temperature ratio of 0.93, and coolant-to-free stream density ratio of 1.06. The cascade employs the hub side blade section and passage geometry of the first stage rotor of GE-E3 turbine engine. The contour endwall profile is employed on the bottom endwall only in the cascade. The blowing ratio of the film-cooling flow varies from 1.0 to 2.4 from 71 discrete cylindrical holes located in the contour endwall. The three-dimensional profile of the endwall varies in height in both the pitchwise and axial directions. The flow field is quantified with the streamwise vorticity and turbulent intensity, pitchwise static pressure difference, flow yaw angle, and pitchwise velocity. Both the flow field and temperature data indicate that the coolant jets cover more distance in the pitchwise and axial direction in the passage as the blowing ratio increases. Thus, the local and average film-cooling effectiveness increase with the blowing ratio.Copyright

Effects of upstream endwall film cooling on a vane cascade flowfield

The effects of film cooling on the endwall region flow and aerodynamic losses are investigated experimentally as the film flow is delivered from the slots in the endwall upstream of a linear vane c...

Three-component particle image velocimetry in a generic can-type gas turbine combustor

A stereoscopic particle image velocimetry system was used to obtain the velocity field of a can-type combustor in the non-reacting condition. In order for these measurements to be taken, an optically accessible can-type forward flow combustor was manufactured. The combustor has a 10-vane swirler in the dome as well as a primary zone with six 9.5 mm holes, a secondary zone with eight 5 mm holes and a dilution zone with ten 11.8 mm holes. The two cooling rings have 30 and 50 × 1.2 mm holes and are placed between the three zones. The main flow features were captured such as the recirculation zones and jets. The more subtle features such as flow entering the swirler, entering the dilution holes from the annulus, and converging into smaller annuli around the secondary and dilution zones were also evident in some sections of the data. An unexpected flow recirculation was observed in the dilution zone. The departure of the flow from the recirculation regions to join the bulk flow in the dilution zone was also shown.