Flowfield and Temperature Profiles Measurements on a Combustor Simulator Dedicated to Hot Streaks Generation

Abstract

In order to deepen the knowledge of the interaction between modern lean burn combustors and high pressure turbines, a real scale annular three sector combustor simulator has been assembled at University of Florence, with the goal of investigating and characterizing the generated aerothermal field and the hot streaks transport between combustor exit and the high pressure vanes location. To generate hot streaks and simulate lean burn combustors behavior, the rig is equipped with axial swirlers, fed by main air flow that is heated up to 531 K, and liners with effusion cooling holes that are fed by air at ambient temperature. The three sector configuration is used to reproduce the periodicity on the central sector and to allow to perform measurements inside the chamber, through the lateral walls. Ducts of different length have been mounted on the swirlers, preserving the hot mainflow from the interaction with coolant. Such configurations, together with the one without ducts, have been tested, using different measurement techniques, in order to highlight the differences in the resulting flow fields. First of all, isothermal PIV measurements have been performed on the combustion chamber symmetry plane, to highlight the mixing phenomena between the mainflow and cooling flows. Then a detailed investigation of the mean aerothermal field at combustor exit has been carried out, for nominal operating conditions, by means of a five hole pressure probe provided with a thermocouple, installed on an automatic traverse system. With the aim of analyzing the hot streaks transport and the flow field modification towards the vanes location, such measurements have been performed on two different planes: one located in correspondence of the combustor exit and the further one placed downstream, in the virtual location of the vanes leading edges. Therefore, an experimental database, describing the evolution of the flow field in a combustor simulator with typical traits of modern lean burn chambers, for different injector geometries, has been set up.

Commissioning of a Combined Hot-Streak and Swirl Profile Generator in a Transonic Turbine Test Facility

“…Koupper et al [20] reported the design of another lean-burn combustor simulator for turbine experiments with temperature distortion and swirl. Characterization experiments conducted using an annular sector facility have since been reported by Bacci et al [21]. However, no experimental data from the fully annular system have been published to date.…”

Clocking and Potential Effects in Combustor–Turbine Stator Interactions

“…In order to characterize the flow characteristics in this plane, different kinds of probes can be used with an automatic traverse system mounted on the flange showed in Figure 1 (right picture, grey component). In particular, a five-hole-probe campaign [17] and a hot-wire-anemometry campaign [18] were carried out in order to check that the rig was able to re-create lean combustor representative flow features at its exit. Both campaigns confirmed the pursued goals, as a significantly non-uniform temperature pattern, within a highly swirling flow, was found on plane 40.…”

Turbulence intensity measurements across a NGV cooled cascade with representative Lean Burn combustor outflow

“…The swirlers design was aimed at creating a representative flow field even without the effect of the combustion process. Ducts of 55mm length (≈ 35% of the total chamber length) were installed on the swirlers, to preserve the swirling mainflow from the interaction with the cooling flows (Bacci et al 2015;Andreini et al 2016). The chamber is characterized by a short distance between the inlet plane and the NGV position (≈ 2.5 times the swirlers diameters) and the inner liner is strongly convergent towards the final part of the chamber with respect to the horizontal axis (Fig.…”