Detailed Velocity and Heat Transfer Measurements in an Advanced Gas Turbine Vane Insert Using Magnetic Resonance Velocimetry and Infrared Thermometry

Abstract

This work reports the results of paired experiments for a complex internal cooling flow within a gas turbine vane using magnetic resonance velocimetry (MRV) and steady-state infrared (IR) thermometry. A scaled model of the leading edge insert for a gas turbine vane with multi-pass impingement was designed, built using stereolithography fabrication methods, and tested using MRV techniques to collect a three-dimensional, three-component velocity field data set for a fully turbulent test case. Stagnation and recirculation zones were identified and assessed in terms of impact on potential cooling performance. A paired experiment employed an IR camera to measure the temperature profile data of a thin, heated stainless steel impingement surface modeling the inside turbine blade wall cooled by the impingement from the vane cooling insert, providing complementary data sets. The temperature data allow for the calculation of wall heat transfer (HT) characteristics, including the Nusselt number distribution for cooling performance analysis to inform design and validate computational models. Quantitative and qualitative comparisons of the paired results show that the flow velocity and cooling performance are highly coupled. Module-to-module variation in the surface Nusselt number distributions is evident, attributable to the complex interaction between transverse and impinging flows within the apparatus. Finally, a comparison with internal HT correlations is conducted using the data from Florschuetz et al. [1981, “Streamwiseflow and Heat Transfer Distributions for Jet Array Impingement With Crossflow,” ASME 1981 International Gas Turbine Conference and Products Show, American Society of Mechanical Engineers. doi:10.1115/1.3244463]. Measurement uncertainty was assessed and estimated to be approximately ±7% for velocity and ranging from ±3% to ±10% for Nusselt number.