Turbine Test Facility

Penn State’s test turbine facilities operate in a continuous-duration mode. The flow is provided by two large compressors which, together, provide 25 lb/s of air up to 70 psia. The compressor discharge flow is split into the main gas path flow for the turbine as well as the secondary cooling air. Current operating temperatures for the main gas path are approximately 450°F, but the rig has been designed to operate as high as 750°F. A dynamometer water brake is used to absorb the energy produced by the turbine and maintain a constant rotational speed. Additional features of the test turbine include: a magnetic bearing system that allows for a range of clearance scenarios; a telemetry system; and CO2 flow tracing capabilities. The test turbine facility was designed to operate in a range that most closely replicates that of a modern turbine. Important non-dimensional Reynolds numbers, which govern the flow physics and heat transfer, are matched to that of the engine.

State-of-the-Art Assessment of Turbine Efficiency and Durability

Efficiency and durability are two main factors when designing turbine hardware. Specialized instrumentation at START is used to assess the thermodynamic efficiency and operating durability of turbine components. A 360° traversing system captures the temperature and pressure fields at the turbine exit plane – fully-defined across numerous circumferential and spanwise locations. Through application of this measurement technique, START is able to resolve variations of efficiency less than 0.1 points. To assess turbine part durability, which is largely driven by hardware temperature, a long wave infrared (LWIR) thermal imaging system measures surface temperature on rotating internally- and externally-cooled turbine blades. This thermal imaging system enables high-fidelity assessment of cooling effectiveness, which supports the identification of next-gen cooling technologies.

Test turbine flow path looking downstream from the in-line natural gas heater towards the one-stage test section.

2D measurements at the turbine exit plane used to quantify turbine efficiency.

Microchannel Coupon Test Facility

The START lab includes a test rig built to collect pressure drop and heat transfer measurements from test coupons that are constructed using direct metal laser sintering. A strong partnership has developed between START and Penn State’s CIMP-3D such that unique microchannels, only made possible through additive manufacturing, can be constructed and fully characterized. In addition to characterizing the pressure drop and heat transfer, the START personnel make full use of the characterization facilities at CIMP-3D including an optical profilometer and an industrial CT scanner to evaluate whether design tolerances are being met as well as surface roughness.

FILM COOLING Coupon Test Facility

The START lab features two benchtop rigs for evaluating overall cooling effectiveness of combined internal and film cooling architectures in a matched Biot number configuration. Primarily used for testing additively manufactured cooling designs, the rigs can also be used to test coupons with cooling features produced with conventional manufacturing methods. These rigs allow manufacturing effects only present in engine relevant materials at engine scale, such as surface roughness, to be studied.

The two different rigs allow for two different coolant delivery conditions: plenum feed (left image), or co/counterflow via an integrated coolant channel (right image). These two configurations allow the cooling of numerous different turbine components to be emulated in the rig. Cooled CO2 gas is used as the coolant to achieve density ratios of 1.7+. Compressed air is used to provide room temperature mainstream flow, enabling mainstream Mach numbers up to 0.6 in both rigs. External surface temperatures are measured with an IR camera via the Zinc-selenide window.