An analytical approach to airfoil icing

Bragg, Michael B.; Gregorek, G. M.; Shaw, R. J.

doi:10.2514/6.1981-403

Cited by 40 publications

(11 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Efforts to analytically model the ice accretion process have been fairly successful for dry ice growth conditions where the thermodynamic analysis is trivial. 2 Experimental results have confirmed the accuracy of droplet trajectory calculations and predicted ice shapes are generally in good agreement with experimentally measured "rime" ice accretions. 3 ' 5 Analytical modeling of the ice accretion process for wet and mixed cases is significantly more difficult due to the need to evaluate both droplet trajectory and thermodynamic considerations and due to the potential for coupling between them.…”

Section: Introductionsupporting

confidence: 82%

“…When the ice surface is dry the freezing fraction is unity. The assumption of steady-state requires that the rate at which energy is added to the control volume equals the rate at which it is removed, i.e., e"in = Q"out (2) where Q" in and Q" out represent the energy added to and removed from, respectively, the control volume per unit area per unit time. Equation (2) may be expanded into its compo-…”

Section: Steady-state Thermodynamic Model For An Icing Surfacementioning

confidence: 99%

See 1 more Smart Citation

Comparison of wet and dry growth in artificial and flight icing conditions

Hansman

Kirby

1987

Journal of Thermophysics and Heat Transfer

View full text Add to dashboard Cite

The heat transfer behavior of accreting ice surfaces in natural (flight test) and simulated (wind tunnel) cloud icing conditions are studied. Observations of wet and dry ice growth regimes as measured by ultrasonic pulseecho techniques are made. Observed wet and dry ice growth regimes at the stagnation point of a cylinder are compared with those predicted using a quasi steady-state heat balance model. A series of heat transfer coefficients are employed by the model to infer the local heat transfer behavior of the actual ice surfaces. The heat transfer in the stagnation region is generally inferred to be higher in wind tunnel icing tests than in natural, flight icing conditions. NomenclatureA,B -experimentally derived constants (-) Q = specific heat capacity of ice* J/kg K C p -specific heat capacity of air, J/kg K C w = specific heat capacity of water, J/kg K D = diffusion coefficient of water vapor in air, mVs d = cylinder diameter, m h = local convective heat transfer coefficient, W/m 2 K k = thermal conductivity of air, W/m K L f = latent heat of fusion of water, J/kg L s = latent heat of sublimation of water, J/kg L v = latent heat of vaporization of water, J/kg L* = effective latent heat of fusion M" = local mass flux/time, kg/m 2 s Nu -Nusselt number (-) Q " = local heat flux/time, W/m 2 Re = Reynolds number based on cylinder diameter and y (X (-) r = recovery factor, 0.875 (-) A TV = cloud supercooling = -T^ (° C) T'surf = equilibrium surface temperature, °Ĉ = cloud temperature, °C T* = effective surface freestream temperature difference, °C t = icing time, s Fa, = freestream velocity, m/s W = cloud liquid water content, g/m 3 18= local collection efficiency (-) Py,surf = saturated vapor density over surface, kg/m 3 p voo = saturated vapor density in cloud, kg/m 3

show abstract

Section: Introductionsupporting

confidence: 82%

Section: Steady-state Thermodynamic Model For An Icing Surfacementioning

confidence: 99%

Comparison of wet and dry growth in artificial and flight icing conditions

Hansman

Kirby

1987

Journal of Thermophysics and Heat Transfer

View full text Add to dashboard Cite

show abstract

“…The computation is an iterative process with a time-stepping procedure where successive thin ice layers are formed on the surface and followed by flow field and droplet impingement recalculations. Performance degradation are calculated using semi-empirical models to estimate lift and drag coefficients [26,27]. The correlations were proposed to predict drag increment due to artificial rime and glaze icing.…”

Section: Ice Accretion Modeling On Hawtmentioning

confidence: 99%

Prediction of ice accretion and performance degradation of HAWT in cold climates

Brahimi¹,

Chocron²,

Paraschivoiu³

1998

1998 ASME Wind Energy Symposium

View full text Add to dashboard Cite

The objective of the present paper is to develop a computer code capable of simulating the shape and amount of ice which may accumulate on horizontal axis wind turbine blades when operating in icing conditions. The resulting code is capable to predict and simulate the formation of ice in rime and glaze conditions, calculate the flow field and particle trajectories, and perform thermodynamic analysis. It also gives the possibility to study the effect of different parameters that influence ice formation such as temperature, liquid water content, droplet diameter and accretion time. The analysis has been conducted on different typical airfoils as well as on NASA/DOE Mod-0 wind turbine. Results showed that ice accretion on wind turbines may reduce the power output by more than 20%.

show abstract

“…It is assumed that the drop-size distribution in the cloud is the same for both scaled and reference cases and that the trajectories can be adequately represented by that of one representative drop diameter. Bragg, et al 4 showed that for the typical distributions of drop size and relative velocity of icing experiments the drop motion and catch on a surface can be accurately represented by using the drop median volume diameter (MVD). Cloud drops involved in Appendix C icing are in the range of 10-to 50-µm diameter; therefore, the effect of gravity is small and can be neglected.…”

Section: Drop Trajectory Similaritymentioning

confidence: 99%