NUMERICAL DEMONSTRATION FOR A NOVEL DESIGN OF HIGH-TEMPERATURE TURBINE FACILITY ENABLED BY SHOCK TUBE

Reproducing the working environment of a gas turbine blade in laboratory has long been a challenge in the state of the art, but is crucial for scaling data from laboratory conditions to engine design point. Specifically, simultaneous matching of Reynolds number, Mach number and turbine inlet temperature in laboratory to those of engine design condition is scarcely achieved in the academic community. As an attempt to tackle this challenge, this paper introduces a novel design of high-temperature turbine cascade, whose mainstream gas is sourced from a shock tube so that high-enthalpy environment is fulfilled. To examine the feasibility of the rig design in obtaining reliable heat transfer data, numerical simulations are conducted, verified and validated against experimental data. Numerical results demonstrate that the new rig is able to produce a mainstream gas of 589 +/- 1 K for a test time of 9.5 ms. Nusselt number obtained during the test time agrees well the experimental data in VKI's isentropic light piston tunnel. Besides, the test duration is sufficient for a steady boundary layer to establish. Furthermore, the new rig is shown to generate a total temperature of 1810 +/- 10 K at the cascade inlet for a test time of 1 ms. However, pseudo shock wave forms under this circumstance, greatly augmenting turbulence intensity at the cascade inlet and leads to an over-predicted Nusselt number compared to the experiment. Control of turbulence intensity at the cascade inlet (shock tube outlet) is required as a scope of the future work.