A single-stage centrifugal compressor designed by Honeywell has been installed at Purdue University to contribute to the experimental database on high-speed, high-pressure ratio centrifugal compressor performance. The rig, which operates at a design speed of 45,000 rpm and a pressure ratio greater than 6, has been extensively instrumented to provide steady and unsteady aerodynamic and aeromechanics data which will be used for tool development and validation.

All current work with the Purdue SSCC rig is funded by Honeywell Aerospace.

Inlet distortion effects on centrifugal compressor aerodynamics

• Modular inlet design allows for experimentation with an auxiliary power unit (APU) -style inlet and axisymmetric research-style inlet on the same centrifugal compressor stage
• Development of the flow field at the aerodynamic interface plane (AIP) with a 360 degree rotatable rake including flow angles and unsteady pressures
• Analysis of the effects of the inlet flow field on the compressor stage including performance, range, and component aerodynamics for stability analysis

Experimental investigation of tip clearance effects

• Active tip clearance control system allows the tip clearance to be actively monitored and changed during operation
• Stage and component level analysis of tip clearance effects and sensitivity of each component
• Development of computational model to aid in understanding of the tip leakage flow development and assess the ability of computational models to predict stage and component performance for different tip clearances

The SSCC compressor is heavily instrumented with over 500 data collection channels for health monitoring and performance, with devices such as pressure transducers, thermocouples, capacitance probes, light probes, and strain gauges. Total temperature/total pressure rakes at the compressor inlet and exit provide information for stage performance data.

Unsteady Instrumentation
Kulite pressure transducers placed along the impeller shroud, vaneless space, and diffuser vanes measure unsteady pressure fluctuations resulting from impeller blade passage. Strain gauges measure the dynamic strain on the impeller. A slip ring translates their signals from the rotating to the stationary reference frame. The strain gauges and Kulite pressure transducers are simultaneously sampled at up to 1 MHz for detailed characterization of unsteady flow phenomena. Additionally, the rig is instrumented with NSMS light probes to measure blade deflections.

Clearance Control
The SSCC rig has an active clearance control system and can actuate the impeller at any speed to take a constant clearance map. Clearances are monitored in real-time by capacitance probes mounted at the inducer, knee, and exducer and are recorded to a resolution of 0.0001”.

Bleed Flow System
Ports at the impeller backface and on the shroud near the diffuser inlet are independently controlled in the SSCC's secondary air system. The bleed flows are measured with separate calibrated venturi meters to quantify the mass flow as a fraction of the bulk flow.

Optical Access
Windows in both inlet configurations enable LDV techniques to capture three-dimensional velocity fields upstream of the impeller leading edge.

1. Bond, E.H., 2022, "Development of a Reduced Computational Model to Replicate Inlet Distortion in an APU-Style Inlet of a Centrifugal Compressor," MS Thesis, School of Aeronautics and Astronautics, Purdue University.


2. Brown, W.J., 2020, "Experimental and Numerical Evaluation of the Performance of a High-Speed Centrifugal Compressor at Off-Design Conditions,", MS Thesis, School of Mechanical Engineering, Purdue University.


3. Fuehne, M.F., 2020, "Experimental and Numerical Investigation of Tip Clearance Effects in a High-Speed Centrifugal Compressor," MS Thesis, School of Aeronautics and Astronautics, Purdue University.


4. Harrison, H.M., 2020, "Development and Validation of a New Method to Model Slip and Work Input for Centrifugal Compressors," PhD. Dissertation, School of Mechanical Engineering, Purdue University.


5. Lou, F., 2016, “A Study on Flow Development in an APU-style Inlet and Its Effect on Centrifugal Compressor Performance.” PhD. Dissertation, School of Mechanical Engineering, Purdue University.