Heat transfer measurements from a smooth NACA 0012 airfoil

Poinsatte, Philip E.; Fossen, G. James Van; Newton, James E.; Witt, Kenneth J. De

doi:10.2514/3.46114

Cited by 27 publications

(18 citation statements)

References 9 publications

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“…A NACA 0012 airfoil was used for this testing as it is well characterized for ice accretion from extensive testing in supercooled liquid water (e.g. [11,12]) thereby eliminating the need to characterize certain aspects of the airfoil. The ice shapes were generated across a series of four different flow conditions where the relative humidity in the plenum was the primary parameter varied.…”

Section: Introductionmentioning

confidence: 99%

Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

Struk¹,

Agui²,

Ratvasky³

et al. 2019

SAE Technical Paper Series

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This paper describes an ice-crystal icing experiment conducted at the NASA Propulsion System Laboratory during June 2018. This test produced ice shape data on an airfoil for different test conditions similar to those inside the compressor region of a turbo-fan jet engine. Mixed-phase icing conditions were generated by partially freezing out a water spray using the relative humidity of flow as the primary parameter to control freeze-out. The paper presents the ice shape data and associated conditions which include pressure, velocity, temperature, humidity, total water content, melt ratio, and particle size distribution. The test featured a new instrument traversing system which allowed surveys of the flow and cloud. The purpose of this work was to provide experimental ice shape data and associated conditions to help develop and validate ice-crystal icing accretion models. The results support previous experimental observations of a minimum melt-ratio threshold for accretion to occur as well as the existence of a plateau region where the icing severity is high for a range of melt ratios. However, a maximum limit for melt ratio, which is suggested in the ice crystal icing literature, was not observed perhaps complicated by the potential for some supercooling of the water at these conditions.

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Section: Introductionmentioning

confidence: 99%

Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

Struk¹,

Agui²,

Ratvasky³

et al. 2019

SAE Technical Paper Series

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“…The non-dimensional radial location (r/R) was described by the ratio of the distance to the placed RTD by the tip radius of the blade. Due to experimental limitations, the RTDs were placed on the nose of the leading edge (S/c = 0), a point known to show some of the most elevated heat transfer rates [43,52]. More chordwise locations are scheduled for testing in the future.…”

Section: Heating Elements and Rtdsmentioning

confidence: 99%

“…The air properties vary with temperature. Therefore, a reference temperature (T f ) was chosen to estimate those properties, similar to [43]. According to [54], the equation can be applied for a flow where V ∝ is a constant and the temperature does not vary markedly in the boundary layer.…”

Section: Convective Heat Transfermentioning

confidence: 99%

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An Experimental Investigation of the Convective Heat Transfer on a Small Helicopter Rotor with Anti-Icing and De-Icing Test Setups

et al. 2021

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Successful icing/de-icing simulations for rotorcraft require a good prediction of the convective heat transfer on the blade’s surface. Rotorcraft icing is an unwanted phenomenon that is known to cause flight cancelations, loss of rotor performance and severe vibrations that may have disastrous and deadly consequences. Following a series of experiments carried out at the Anti-icing Materials International Laboratory (AMIL), this paper provides heat transfer measurements on heated rotor blades, under both the anti-icing and de-icing modes in terms of the Nusselt Number (Nu). The objective is to develop correlations for the Nu in the presence of (1) an ice layer on the blades (NuIce) and (2) liquid water content (LWC) in the freestream with no ice (NuWet). For the sake of comparison, the NuWet and the NuIce are compared to heat transfer values in dry runs (NuDry). Measurements are reported on the nose of the blade-leading edge, for three rotor speeds (Ω) = 500, 900 and 1000 RPM; a pitch angle (θ) = 6°; and three different radial positions (r/R), r/R = 0.6, 0.75 and 0.95. The de-icing tests are performed twice, once for a glaze ice accretion and another time for rime ice. Results indicate that the NuDry and the NuWet directly increased with V∝, r/R or Ω, mainly due to an increase in the Reynolds number (Re). Measurements indicate that the NuWet to NuDry ratio was always larger than 1 as a direct result of the water spray addition. NuIce behavior was different and was largely affected by the ice thickness (tice) on the blade. However, the ice acted as insulation on the blade surface and the NuIce to NuDry ratio was always less than 1, thus minimizing the effect of convection. Four correlations are then proposed for the NuDry, the NuWet and the NuIce, with an average error between 3.61% and 12.41%. The NuDry correlation satisfies what is expected from heat transfer near the leading edge of an airfoil, where the NuDry correlates well with Re0.52.

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“…The two temperatures are shown in dashed lines and correlate with each other very well. The chart on the bottom is the calculated heat transfer coefficient comparison from Equation 11.…”

Section: Figure 6 Sample Heat Transfer Time History Datamentioning

confidence: 99%

Transient Heat Transfer Measurements of Surface Roughness due to Ice Accretion

Han

Palacios

2014

6th AIAA Atmospheric and Space Environments Conference

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A high-resolution, non-intrusive heat transfer measurement method based on Infra-Red thermography and transient heat transfer analysis is presented. This technique was successfully applied to NACA 0012 airfoils with castings of natural accreted ice surface roughness. A total of 11 representative icing conditions were reproduced at the Adverse Environment Rotor Test Stand (AERTS) facility at the Pennsylvania State University. The ice roughness was retained using ice molding and casting techniques. Roughness on casting models was categorized into a smooth zone and a rough zone. Smooth to rough zone transition location and ice limit of each case was recorded. Arithmetic averages of roughness height (R a ) were calculated for 8 locations on the chordwise direction for each of the casting models. Heat transfer measurement was conducted in a low-speed wind tunnel using thermal transient infra-red measurement techniques as well as multiple embedded heat flux and thermocouple sensors. The measured heat transfer coefficient was non-dimensionalized using Frossling numbers to account for the Reynolds variations between the compared tests. The Frossling number and roughness data were compared to LEWICE predictions in a parametric study. The effects of temperature, velocity, droplet size, liquid water content, and icing time on the heat transfer coefficient and Frossling number were examined. An overprediction of LEWICE roughness height and corresponding heat transfer rate was quantified. A 200% to 391% over-prediction of the peak heat transfer value was identified from the comparison between LEWICE prediction and experimental measurements. NomenclatureAERTS = Adverse Environment Rotor Test Stand c = Specific heat, J/(kg· K) chord = chord length of airfoil, m h = Convective heat transfer coefficient, W/(m 2 · K) k = Thermal conductivity, W/(m· K) LWC = Cloud Liquid Water Content, g/m 3 MVD = Water droplet Medium VolumeDiameter, µm RPM = Rotational speed, revolution per minute s/c = Nondimensionalized surface wrap distance, distance/chord t = Transient time, s T = Surface temperature, K T i = Initial surface temperature, K T ∞ = Free Stream temperature of air, K V = Free-stream velocity of air, m/s α = Thermal diffusivity, m 2 /s β = Characteristic number for transient heat conduction, dimensionless ρ = Density, kg/m 3 θ = Normalized temperature, dimensionless ζ = Combined position and time variable, dimensionless

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Heat transfer measurements from a smooth NACA 0012 airfoil

Cited by 27 publications

References 9 publications

Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

An Experimental Investigation of the Convective Heat Transfer on a Small Helicopter Rotor with Anti-Icing and De-Icing Test Setups

Transient Heat Transfer Measurements of Surface Roughness due to Ice Accretion

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