Experimental and numerical investigations on aircraft icing at mixed phase conditions

Baumert, Arne; Bansmer, Stephan; Trontin, Pierre; Villedieu, Philippe

doi:10.1016/j.ijheatmasstransfer.2018.02.008

Cited by 69 publications

(60 citation statements)

References 44 publications

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“…Icing of the sensor domes results from water vapor deposition or contact freezing of supercooled droplets in clouds or fog and can significantly influence the measurements of solar and terrestrial irradiance. The sensor icing strongly depends on the environmental conditions such as temperature, liquid water content, cloud droplet size, and horizontal wind speed (Baumert et al, 2018), which makes an automated filtering of the data impossible. To monitor icing of the sensor domes, the BP contains a digital camera pointing towards the pyranometers.…”

Section: Ice Flaggingmentioning

confidence: 99%

The new BELUGA setup for collocated turbulence and radiation measurements using a tethered balloon: First applications in the cloudy Arctic boundary layer

Egerer¹,

Gottschalk²,

Siebert³

et al. 2019

Preprint

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Abstract. The new BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) tethered balloon system is introduced. It combines a set of instruments to measure turbulent and radiative parameters and energy fluxes. BELUGA enables collocated measurements either at a constant altitude or as vertical profiles up to 1.5 km height. In particular, the instrument payload of BELUGA comprises three modular instrument packages for high resolution meteorological, wind vector and broadband radiation measurements. The collocated data acquisition allows to estimate the driving parameters of the energy balance in various altitudes. Heating rates and net irradiances can be related to turbulent fluxes and local turbulence parameters such as dissipation rates. In this paper the technical setup, the instrument performance, and the measurement strategy of BELUGA are explained. Furthermore, the high vertical resolution due to the slow ascent speed is highlighted as a major advantage of tethered balloon-borne observations. Three illustrative case studies of the first application of BELUGA in the Arctic atmospheric boundary layer are presented. As a first example, measurements of a single layer stratocumulus are discussed. They show a pronounced cloud top radiative cooling of up to 6 K h−1. To put this into context, a second case elaborates respective measurements with BELUGA in a cloudless situation. In a third example, a multi layer stratocumulus was probed, revealing reduced turbulence and negligible cloud top radiative cooling for the lower cloud layer. In all three cases the net radiative fluxes are much higher than turbulent fluxes. Altogether, BELUGA has proven its robust performance in cloudy conditions of the Arctic atmospheric boundary layer.

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Section: Ice Flaggingmentioning

confidence: 99%

The new BELUGA setup for collocated turbulence and radiation measurements using a tethered balloon: First applications in the cloudy Arctic boundary layer

Egerer¹,

Gottschalk²,

Siebert³

et al. 2019

Preprint

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“…The use of the whole database (from run #17 to run #101) with the whole range of melting ratios allows to validate the model for the plateau effect. In the meantime, a validation can be found in Baumert et al (2018) on the basis of the experiments conducted at TU Braunschweig under mixed-phase conditions. Figure 6 shows the time evolution of the computed ice shapes for runs #17, #77, #92 and #101.…”

Section: Model Validationmentioning

confidence: 99%

“…At higher melting ratios, the cone angle has become smaller as observed for past experiments where the wet bulb temperature was higher than the freezing point (glaciated conditions, see below). A detailed review dedicated to the experimental studies in mixed phase conditions can be found in Baumert et al (2018).…”

Section: Introductionmentioning

confidence: 99%

A comprehensive accretion model for glaciated icing conditions

Trontin

Villedieu

2018

International Journal of Multiphase Flow

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Icing has been identified as a major hazard for aviation safety since the beginning of aeronautical engineering. This paper is focused on ice crystal icing (ICI) which is related to ice accretion for an aircraft in flight in the presence of ice particles. Liquid water is necessary for the ice crystals to stick to the walls of the internal components of an aircraft engine. Emphasis is put on the glaciated conditions where the required liquid water comes from the melting of the ice crystals themselves when they enter a warm environment (the engine core). ICI represents an important concern for flight safety in addition to classical supercooled water icing where the accreted ice only derives from the instantaneous freezing of supercooled liquid droplets when they hit an obstacle. A semi-empirical model which accounts for the influence of the ice crystals on the mass and momentum balance equations is proposed. It accounts for the liquid transport in the porous ice layer and for the ice crystal sticking efficiency. The physics is extremely complicated and not completely understood. Therefore, several adjustable parameters are used in the model. However, the model predictions agree well with the existing experimental data. In particular, the model is able to predict typical conical accretion shapes that are never found in classical supercooled water icing conditions. Moreover, the influence of the ice crystal melting ratio on the accretion shapes is properly accounted for.

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“…Comprehensive investigations on ice accretion of generic test models at mixed phase conditions have been performed in the recent past (Bansmer and Baumert, 2017;Baumert et al, 2018). The test models have been equipped with heat foils to investigate the effect of internal heat conduction on the accretion process.…”

Section: Mixed Phase Icing Of a Cylindermentioning

confidence: 99%

Design, construction and commissioning of the Braunschweig Icing Wind Tunnel

et al. 2018

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Abstract. Beyond its physical importance in both fundamental and climate research, atmospheric icing is considered as a severe operational condition in many engineering applications like aviation, electrical power transmission and wind-energy production. To reproduce such icing conditions in a laboratory environment, icing wind tunnels are frequently used. In this paper, a comprehensive overview on the design, construction and commissioning of the Braunschweig Icing Wind Tunnel is given. The tunnel features a test section of 0.5 m × 0.5 m with peak velocities of up to 40 m s−1. The static air temperature ranges from −25 to +30 ∘C. Supercooled droplet icing with liquid water contents up to 3 g m−3 can be reproduced. The unique aspect of this facility is the combination of an icing tunnel with a cloud chamber system for making ice particles. These ice particles are more realistic in shape and density than those usually used for mixed phase and ice crystal icing experiments. Ice water contents up to 20 g m−3 can be generated. We further show how current state-of-the-art measurement techniques for particle sizing are performed on ice particles. The data are compared to those of in-flight measurements in mesoscale convective cloud systems in tropical regions. Finally, some applications of the icing wind tunnel are presented.

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Experimental and numerical investigations on aircraft icing at mixed phase conditions

Cited by 69 publications

References 44 publications

The new BELUGA setup for collocated turbulence and radiation measurements using a tethered balloon: First applications in the cloudy Arctic boundary layer

The new BELUGA setup for collocated turbulence and radiation measurements using a tethered balloon: First applications in the cloudy Arctic boundary layer

A comprehensive accretion model for glaciated icing conditions

Design, construction and commissioning of the Braunschweig Icing Wind Tunnel

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