NASA Glenn Icing Research Tunnel: 2012 Cloud Calibration Procedure and Results

Three-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulations using theMenter-SST turbulence model were performed on the new 2012 configuration of the NASA Glenn Icing Research Tunnel (IRT). The IRT was simulated from the exit of the heat exchanger to the test section. A two-dimensional simulation was first performed on a crosssection of the heat exchanger to provide initial conditions for three-dimensional flow predictions through the turning vanes, spray bars, tunnel contraction and test section. The simulations showed a general increase in turbulence intensity within the test section as compared to previous IRT configurations (in 2000 and 2009) which can be attributed to wake effects from both the heat exchanger and spray bars. In addition, the heat exchanger produced variations in the yaw flow angles after the turning vanes which are consistent with experiments while the corner geometry resulted in higher flow turbulence gradients for the inner wall regions. Using these simulated time-averaged flowfields, droplet trajectories were predicted using Lagrangian calculations with an unsteady Discrete Random Walk (DRW) model to mimic turbulent fluctuations. A transfer map was developed by mapping the water droplet locations at the test section by tracking peak concentration contours associated with both nozzle rows and nozzle columns. In addition, the liquid water concentration (LWC) distribution at the test section was predicted using the 2012 calibrated nozzle locations. The simulated transfer map and LWC distribution were both qualitatively similar to experiments but demonstrate that the RANS model may not be capturing unsteadiness associated with the spray bar wakes and the jets. An appendix was provided with data on a hybrid RANS/LES simulation of a section of the IRT which captured the unsteady behavior of the airflow. The hybrid model predicts significantly higher turbulence in the spray bar wake than the RANS model which would explain the disparities between with the droplet trajectory calculations and experiments. Nomenclature α = liquid water concentration C(d) = cumulative distribution function d = droplet diameter d rr = Rosin-Rammler reference diameter h rr = Rosin-Rammler spread parameter k = turbulent kinetic energy k av = average turbulent kinetic energy l = turbulent length scale u = air flow velocity v = water droplet velocity ω = specific dissipation rate x = streamwise distance y = vertical distance y+ = dimensionless wall distance z = spanwise distance

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“…26. 4 . The experiments determine the concentration using the same grid and ice measurements that were used to generate the transfer map.…”

Section: Figure 23 Droplet Locations At the Test Section For Every Nmentioning

confidence: 95%

Air Flow and Liquid Water Concentration Simulations of the 2012 NASA Glenn Icing Research Tunnel

Clark

Malinowski

Loth

et al. 2012

4th AIAA Atmospheric and Space Environments Conference

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“…9 The half-pipe is the sensor used for TWC measurements, the other two MW elements, however, are useful for indicating percent freeze-out or the percentage of ice crystal to liquid water at the measurement point. Because the wires are heated, they will have a response even in a 100% ice crystal environment 6,10 . This response is typically less than 10% of the TWC.…”

Section: Single Point Measurementsmentioning

confidence: 99%

NASA Glenn Propulsion Systems Lab: 2012 Inaugural Ice Crystal Cloud Calibration

Zante

Rosine

2014

6th AIAA Atmospheric and Space Environments Conference

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The inaugural calibration of the ice crystal and supercooled liquid water clouds generated in NASA Glenn's engine altitude test facility, the Propulsion Systems Lab (PSL) is reported herein. This calibration was in support of the inaugural engine ice crystal validation test. During the Fall of 2012 calibration effort, cloud uniformity was documented via an icing grid, laser sheet and cloud tomography. Water content was measured via multiwire and robust probes, and particle sizes were measured with a Cloud Droplet Probe and Cloud Imaging Probe. The environmental conditions ranged from 5,000 to 35,000 ft, Mach 0.15 to 0.55, temperature from +50 to -35 F and relative humidities from less than 1% to75% in the plenum. NomenclatureCDP = Cloud Droplet Probe, drop sizer, 2-50 um CIP = Cloud Imaging Probe Grayscale, drop sizer, 15-930 um DeltaP = Pwat -Pair (psid) GPM = gallons per minute (water flow rate) IRT = Icing Research Tunnel LWC = Liquid Water Content (g/m3) MVD = Median Volumetric Diameter (um) MW = Multi-wire, water content sensor Pair = spray nozzle atomizing air pressure (psig) PSL = Propulsion Systems Laboratory Pwat = spray nozzle water pressure (psig) RH = Relative Humidity RP = Robust Probe S#### = Calibration test spray condition (4-digit number) SBCA = spray bar cooling air STA 1 = calibration plane in the 36-in duct TWC = Total Water Content (g/m3) um = micron

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“…Other components of the calibration results are presented elsewhere. Specifically, these include the results of the icing cloud calibration [2] and of the aero-thermal characteristics of the test section [3]. The University of Virginia also contributed to the calibration of the tunnel using three-dimensional Reynold-Average NavierStokes (RANS) simulations on the 2012 configuration of the IRT [4].…”

Section: Introductionmentioning

confidence: 99%