Icing on a Non-Rotating Cylinder Under Conditions of High Liquid Water Content in the Air: I. Form and Size of Ice Deposits

AbstractIce accretion on a non-rotating cylinder was studied under icing conditions involving a wet-growth (glaze) process. Experiments were performed in an outdoor wind tunnel designed for icing studies. In this paper, the experimental method is introduced and the characteristics of form, size, and time development of deposits are given. In terms of freezing conditions, these characteristics were found to be very complex, in which all the external effects: air temperature, wind conditions, liquid water content in the air, and accretion time, are of the same order of importance. In a wet-growth process there exists above the icing surface a water film, the behaviour and dynamics of which are affected by various variables. The water film seems to play an important role in the wet-growth icing.

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The Influence of Successive Thermals on Entrainment and Dilution in a Simulated Cumulus Congestus

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-16-0144.1 ◽

2017 ◽

Vol 74 (2) ◽

pp. 375-392 ◽

Cited By ~ 14

Author(s):

Daniel H. Moser ◽

Sonia Lasher-Trapp

Keyword(s):

Water Content ◽

Liquid Water ◽

Liquid Water Content ◽

Cumulus Clouds ◽

1D Modeling ◽

Idealized Modeling ◽

Cumulus Congestus ◽

Multiple Clouds ◽

Future Work ◽

High Liquid Water Content

Abstract Cumulus clouds are frequently observed as comprising multiple successive thermals, yet numerical simulations of entrainment have not investigated this level of detail. Here, an idealized simulated cumulus congestus consisting of three successive thermals is used to analyze and understand their role in maintaining the high liquid water content in the core of the cloud, which past 1D modeling studies have suggested can ultimately determine its ability to precipitate. Entrainment and detrainment are calculated directly at the edge of the cloud core at frequent time intervals. Entrainment maxima occur at the rear of the toroidal circulation associated with each thermal and thus are transient features in the lifetime of multithermal clouds. The evolution of the least diluted parcels within each thermal shows that the entrainment rates alone cannot predict the erosion of the high liquid water content cores. A novel analysis of samples of entrained and detrained air within each successive thermal illustrates tendencies for even positively buoyant air, containing condensate, to be entrained by later thermals that rise in the wakes of their predecessors, limiting their dilution. The later thermals can achieve greater depths and produce precipitation when a single thermal could not. Future work is yet needed to evaluate the generality of these results using multiple clouds simulated in different environments with less-idealized modeling frameworks. Implications for current cumulus parameterizations are briefly discussed.

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Transient atmospheric ice accretion on wind turbine blades

Wind Engineering ◽

10.1177/0309524x18780380 ◽

2018 ◽

Vol 42 (6) ◽

pp. 596-606

Author(s):

Galal M Ibrahim ◽

Kevin Pope ◽

Yuri S Muzychka

Keyword(s):

Wind Turbine ◽

Water Content ◽

Liquid Water ◽

Turbine Blades ◽

Liquid Water Content ◽

Single Shot ◽

Ice Accretion ◽

Wind Turbine Blades ◽

Median Volume ◽

Blade Section

This article aims to predict ice loads on a wind turbine blade section at 80% of blade span, using FENSAP ICE. Using low and high liquid water content conditions of stratiform and cumuliform clouds, different icing events are simulated. Ice accretion predictions with single-shot and multi-shot approaches are presented. Blade surface roughness is also investigated, as well as the relationships between ice mass, liquid water content, median volume diameter, and temperature.

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The effects of high liquid water content on thunderstorm charging

Journal of Geophysical Research Atmospheres ◽

10.1029/92jd01186 ◽

1992 ◽

Vol 97 (D13) ◽

pp. 14671 ◽

Cited By ~ 46

Author(s):

C. P. R. Saunders ◽

I. M. Brooks

Keyword(s):

Water Content ◽

Liquid Water ◽

Liquid Water Content ◽

High Liquid Water Content

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Ice Accretion Under Natural and Laboratory Conditions

Annals of Glaciology ◽

10.1017/s0260305500010417 ◽

1985 ◽

Vol 6 ◽

pp. 225-228

Author(s):

K. Itagaki ◽

G. E. Lemieux ◽

H. W. Bosworth

Keyword(s):

Transition Temperature ◽

Water Content ◽

New Hampshire ◽

Liquid Water ◽

Laboratory Experiments ◽

Liquid Water Content ◽

Wind Tunnels ◽

Ice Accretion ◽

Natural Conditions ◽

Possible Cause

To compare results of icing studies conducted in wind tunnels with natural icing conditions, a series of rotor icing studies were made on top of Mt. Washington, New Hampshire. The results indicated that considerable differences exist between the two under conditions of similar liquid water content and temperature. The wet-to-dry growth transition temperature, for instance, with comparable temperature and liquid water content, may be more than 10°C higher under natural conditions than in wind tunnel studies. The possible cause of such discrepancies was found to be the vapor saturation existing in most laboratory experiments. The transition temperature of ice accretion measured in natural fog on board an aircraft agreed better with the results of the Mt. Washington study.

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EXPERIMENTAL AND NUMERICAL INVESTIGATION OF ICE ACCRETION ON AIRFOIL

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194512008793 ◽

2012 ◽

Vol 19 ◽

pp. 227-236

Author(s):

FANXIN MENG ◽

WEIJIAN CHEN ◽

DALIN ZHANG ◽

HUI MA

Keyword(s):

Water Content ◽

Liquid Water ◽

Test Section ◽

Liquid Water Content ◽

Open Circuit ◽

Ice Accretion ◽

Wing Model ◽

Aluminum Cylinder ◽

Ice Shapes ◽

Coated Slide

Open Circuit Icing Research Tunnel was developed to test the ice shape under simulated icing conditions. Standard icing blade technique was used to measure liquid water content (LWC) in the icing tunnel test section. The uniformity of liquid water content was assessed by accreting ices on aluminum cylinder bars. Mean volumetric diameter (MVD) of the spray cloud was determined by soot-coated slide and verified through the limits of impingement. Ice accretion tests were performed on a NACA0012 wing model in typical rime and glaze conditions. Results were compared to ice shapes numerically predicted by Messinger method in the same conditions. It is indicated that good overall agreement is achieved in both icing shape and impingement limit.

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Liquid Water Content and Droplet Size Distribution Mass Fractions for Wind Milling Engine Fan Blade Ice Accretion Analysis

10.4271/2007-01-3291 ◽

2007 ◽

Author(s):

R. Elangovan ◽

M. D. Breer

Keyword(s):

Water Content ◽

Size Distribution ◽

Droplet Size ◽

Liquid Water ◽

Droplet Size Distribution ◽

Liquid Water Content ◽

Ice Accretion ◽

Mass Fractions ◽

Fan Blade

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Ice Accretion Under Natural and Laboratory Conditions

Annals of Glaciology ◽

10.3189/1985aog6-1-225-228 ◽

1985 ◽

Vol 6 ◽

pp. 225-228

Author(s):

K. Itagaki ◽

G. E. Lemieux ◽

H. W. Bosworth

Keyword(s):

Transition Temperature ◽

Water Content ◽

New Hampshire ◽

Liquid Water ◽

Laboratory Experiments ◽

Liquid Water Content ◽

Wind Tunnels ◽

Ice Accretion ◽

Natural Conditions ◽

Possible Cause

To compare results of icing studies conducted in wind tunnels with natural icing conditions, a series of rotor icing studies were made on top of Mt. Washington, New Hampshire. The results indicated that considerable differences exist between the two under conditions of similar liquid water content and temperature. The wet-to-dry growth transition temperature, for instance, with comparable temperature and liquid water content, may be more than 10°C higher under natural conditions than in wind tunnel studies. The possible cause of such discrepancies was found to be the vapor saturation existing in most laboratory experiments. The transition temperature of ice accretion measured in natural fog on board an aircraft agreed better with the results of the Mt. Washington study.

Download Full-text