Turbocharger Lab

 

The Turbocharger Lab is designed to accommodate a range of turbochargers, while combining numerous steady and unsteady measurement capabilities. The turbocharger bench is located within a hemi-anechoic chamber to reduce the impact of reflected sound waves on external acoustic measurements.

A Quincy QSI-750 screw compressor supplies mass flow rates in excess of 0.5 kg/s at pressure ratios of up to 6:1 to drive the turbine. Pressure fluctuations from the screw compressor are suppressed by a large, in-line accumulator tank, providing steady flow to the turbine. A 15 kW electric heater is incorporated to warm up the flow upstream of the turbine in order to increase the power delivered to the compressor and extend its operating range.

The turbine and compressor loops are isolated from one another to decouple the mass flow rates, allowing maximum flexibility. Precise compressor and turbine operating points are obtained through computer-controlled pneumatic valves, installed upstream of the turbine and downstream of the compressor.

Equipment

  • Variety of Kistler/PCB/Validyne in-duct pressure transducers and digital amplifiers;
  • External PCB free-field microphone array
  • PicoTurn eddy current speed sensor with 200 rpm to 400 krpm range
  • Custom-built fast-response type T and standard 1/16” type K thermocouples
  • Oil system, including a pump, regulator, heater and cooler to provide lubrication to the bearing housing at a controlled temperature and pressure
  • Calibrated orifice flow meters on both the turbine and compressor loops
  • A data acquisition system equipped with a National Instruments cDAQ-9178 chassis providing 32 channels of thermocouple measurements, 8 channels of 0-20 mA input, and 8 channels of 0-20 mA output. Acoustic measurements are acquired with 12 channels, simultaneously sampled at 50 kHz. A NI PXIe-1073 chassis also allowing for 16 channels of variable input voltage at a 1.25 MHz simultaneous sampling rate and 8 channels of input 0-5 V at a 250 kHz simultaneous sampling rate
  • A LaVision time-resolved, stereo Particle Image Velocimetry (PIV) system to measure the velocity field within the compression system of a turbocharger. The primary components of this system include: dual-cavity Nd:YLF high repetition rate laser with adjustable light sheet optics, pair of high-speed cameras, sub-micron flow seeder, high speed controller, and workstation PC with DaVis software package. Neutrally buoyant oil particles are introduced to the flow field, where they are illuminated by a laser sheet. By simultaneously capturing successive images with a small (typically a few microseconds) time separation, the movement of oil particles is statistically tracked, and all three velocity components can be spatially resolved on the laser sheet.

Capabilities

  • Characterize the performance of both the compressor and turbine of turbochargers by generating detailed, steady-flow operating maps capable of extending beyond the conventional knowledge
  • Capture the unsteady pressure fluctuations resulting from flow instabilities (surge) in centrifugal compressors at low flow rates by employing a variety of in-duct pressure transducers along with external microphones
  • Investigate in detail the broadband noise associated with flow separation within compressors and discrete tones due to surge and/or blade passing, hence develop the acoustic maps of compressors
  • Identify the compressor surge line as a function of geometrical changes in the overall compression system
  • Capture the temperature oscillations specifically during the reversed flow in compressors through fast-response thermocouples
  • Examine the turbine performance as a function of wastegate or variable geometry vane position by use of a computer-controlled linear actuator
  • Offer a compelling bench-top approach in conjunction with the nonlinear flow simulations within particularly the compression system to better understand the inherent physics, leading to the development of improved predictive tools.

 

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