Analysis of Ice Accretion on Vertical Surfaces of Marine Vessels and Structures in Arctic Conditions

2015 ◽  
Author(s):  
Alireza Dehghani-sanij ◽  
Yuri S. Muzychka ◽  
Greg F. Naterer
Keyword(s):  
Offshore Structures ◽  
Power Lines ◽  
Sea Spray ◽  
Ice Accretion ◽  
Spray Process ◽  
Theoretical Predictions ◽  
Arctic Conditions ◽  
Marine Vessels ◽  
Improved Accuracy ◽  
Good Agreement

The phenomenon of icing in cold climates is a challenging problem of engineering analysis, which involves heat transfer, phase change and multiphase flow with water droplets. This phenomenon has an important impact on the performance and operation of marine vessels, offshore structures, and others such as wind turbines, power lines, and aircraft surfaces. In this paper, a predictive icing model for large vertical surfaces of a marine vessel is developed theoretically. The total flux of sea-spray, including wave spray and wind spray, is analyzed during the spray process. By using heat, mass and salt concentration balances, the freezing fraction, temperature distribution, ice layer thickness, and liquid film thickness are determined. The results are compared with the numerical and experimental results of other studies. Good agreement between the theoretical predictions and other results demonstrates the improved accuracy of the proposed method over past models.

Predicted Ice Accretion on Horizontal Surfaces of Marine Vessels and Offshore Structures in Arctic Regions

2016 ◽  
Author(s):  
Alireza Dehghani-Sanij ◽  
Yuri S. Muzychka ◽  
Greg F. Naterer
Keyword(s):  
Water Film ◽  
Theoretical Method ◽  
Offshore Structures ◽  
Sea Spray ◽  
Ice Accretion ◽  
Wave Direction ◽  
Arctic Regions ◽  
Air Temperatures ◽  
The Stability ◽  
Marine Vessels

Sea spray icing is one of the most significant problems for the operation of marine vessels and offshore structures in Arctic regions. This phenomenon affects the stability of marine vessels and offshore structures, and also the safety of human activities onboard. In this paper, a new predictive icing model for large horizontal surfaces of a marine vessel is developed. To obtain the total flux of sea spray during the icing process, both wind spray and wave spray are considered. By applying heat, mass and salt concentration balances, the freezing fraction, temperature distribution, ice layer and water film thicknesses are determined. Moreover, the effects of different parameters on the freezing fractions at various air temperatures are investigated. The results indicate that air temperature, wind velocity, vessel speed, spray water salinity, height from the water surface, and angle between the vessel heading and wind/wave direction are major parameters in the growth rate of the ice. This theoretical method provides a reasonably accurate and simple way for predicting the sea spray icing phenomena on marine vessels and offshore structures.

Sea spray icing: The physical process, and review of prediction models and winterization techniques

2021 ◽  
pp. 1-26
Author(s):  
Sujay Deshpande ◽  
Ane Sæterdal ◽  
Per-Arne Sundsbø
Keyword(s):  
Prediction Models ◽  
Offshore Structures ◽  
Cold Climate ◽  
Working Environment ◽  
The Arctic ◽  
Design Stage ◽  
Sea Spray ◽  
Ice Accretion ◽  
Sea Wind ◽  
The Impact

Abstract Ice accretion on marine vessels and offshore structures is a severe hazard in the Polar Regions. There is increasing activities related to oil and gas exploration, tourism, cargo transport, and fishing in the Arctic. Ice accretion can cause vessel instability, excess load on marine structures and represents a safety risk for outdoor working environment and operations. Freezing sea spray is the main contributor to marine icing. For safe operations in cold climate, it is essential to have verified models for prediction of icing. Sea spray icing forecast models have improved. Empirical and theoretical models providing icing rates based may be useful as guidelines. For predicting the distribution of icing on a surface at the design stage, Computational Fluid Dynamics has to be applied along with a freezing module. State-of-the-art models for numerical simulation of sea spray icing are still not fully capable of modelling complex ship-sea-wind interactions with spray generation and impact of shipped water. Existing models include good understanding of spray flow effects and freezing. Further development should focus on developing models for dynamic ship-sea-wind interactions, in particular including spray generation, effects of shipped water and distribution of icing on the vessel surface. More experimental and full-scale data is needed for development and verification of new and improved models. Models that estimate ice distribution may improve the winterization design process and reduce effort required for de-icing. Improved methods for de-icing and anti-icing will reduce the impact of sea spray icing and increase safety for marine operations in cold waters.

Sea spray icing phenomena on marine vessels and offshore structures: Review and formulation

2017 ◽  
Vol 132 ◽  
pp. 25-39 ◽  
Author(s):  
A.R. Dehghani-Sanij ◽  
S.R. Dehghani ◽  
G.F. Naterer ◽  
Y.S. Muzychka
Keyword(s):  
Offshore Structures ◽  
Sea Spray ◽  
Marine Vessels

PREDICTING AND REDUCING GLAZE ICE ACCRETION ON ELECTRIC POWER LINES WITH JOULE HEATING: THEORY AND EXPERIMENTS

1999 ◽  
Vol 23 (1A) ◽  
pp. 51-70 ◽  
Author(s):  
G.F. Naterer ◽  
H. Deng ◽  
N. Popplewell
Keyword(s):  
Electric Power ◽  
Joule Heating ◽  
Power Transmission ◽  
Power Lines ◽  
Ice Accretion ◽  
Freezing Rain ◽  
Ambient Temperatures ◽  
Ice Accumulation ◽  
Air Interface ◽  
Theoretical Predictions

An analytical model is developed for the prediction of glaze ice accretion with runback water for electric power lines including the Joule heating effect. In this model, the external air flow is coupled with the liquid film flow by slip (non-zero velocity) boundary conditions a the liquid-air interface. In this way, corrections to previous rime ice models are given in order to account for runback water and its effect on wet ice growth in freezing rain conditions with ambient temperatures slightly below 0[°C]. Also, the process of Joule heating in icing conditions is examined from a thermodynamic optimization viewpoint in a manner which permits efficient power transmission while dissipating heat in order to reduce ice accumulation. Good agreement is achieved between theoretical predictions of the glaze ice accretion and experimental results from the freezing rain simulator at the University of Manitoba.

Computer Modeling of a Tire under Cornering Loads

1989 ◽  
Vol 17 (2) ◽  
pp. 86-99 ◽  
Author(s):  
I. Gardner ◽  
M. Theves
Keyword(s):  
Finite Element Analysis ◽  
Geometric Approach ◽  
Lateral Force ◽  
Slip Angle ◽  
Element Analysis ◽  
Pressure Distributions ◽  
Slip Effects ◽  
Improved Accuracy ◽  
Nonlinear Geometric ◽  
Good Agreement

Abstract During a cornering maneuver by a vehicle, high forces are exerted on the tire's footprint and in the contact zone between the tire and the rim. To optimize the design of these components, a method is presented whereby the forces at the tire-rim interface and between the tire and roadway may be predicted using finite element analysis. The cornering tire is modeled quasi-statically using a nonlinear geometric approach, with a lateral force and a slip angle applied to the spindle of the wheel to simulate the cornering loads. These values were obtained experimentally from a force and moment machine. This procedure avoids the need for a costly dynamic analysis. Good agreement was obtained with experimental results for self-aligning torque, giving confidence in the results obtained in the tire footprint and at the rim. The model allows prediction of the geometry and of the pressure distributions in the footprint, since friction and slip effects in this area were considered. The model lends itself to further refinement for improved accuracy and additional applications.

scholarly journals A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 830
Author(s):  
Julio Cesar Martinez-Garcia ◽  
Alexandre Serraïma-Ferrer ◽  
Aitor Lopeandía-Fernández ◽  
Marco Lattuada ◽  
Janak Sapkota ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Nanocomposites ◽  
Mechanical Reinforcement ◽  
Future Studies ◽  
Three Phase ◽  
Theoretical Predictions ◽  
Filler Network ◽  
New Research ◽  
Good Agreement ◽  
Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

scholarly journals Patch antenna sensor for wireless ice and frost detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan Kozak ◽  
Kasra Khorsand ◽  
Telnaz Zarifi ◽  
Kevin Golovin ◽  
Mohammad H. Zarifi
Keyword(s):  
Resonant Frequency ◽  
Patch Antenna ◽  
Wide Band ◽  
Power Lines ◽  
Ice Thickness ◽  
Ice Accretion ◽  
Robust Method ◽  
Frequency Shifts ◽  
Resonant Amplitude ◽  
Recorded Data

AbstractA patch antenna sensor with T-shaped slots operating at 2.378 GHz was developed and investigated for wireless ice and frost detection applications. Detection was performed by monitoring the resonant amplitude and resonant frequency of the transmission coefficient between the antenna sensor and a wide band receiver. This sensor was capable of distinguishing between frost, ice, and water with total shifts in resonant frequency of 32 MHz and 36 MHz in the presence of frost and ice, respectively, when compared to the bare sensor. Additionally, the antenna was sensitive to both ice thickness and the surface area covered in ice displaying resonant frequency shifts of 2 MHz and 8 MHz respectively between 80 and 160 μL of ice. By fitting an exponential function to the recorded data, the freezing rate was also extracted. The analysis within this work distinguishes the antenna sensor as a highly accurate and robust method for wireless ice accretion detection and monitoring. This technology has applications in a variety of industries including the energy sector for detection of ice on wind turbines and power lines.

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

Theoretical Prediction of Motions of High-Speed Planing Boats in Waves

1978 ◽  
Vol 22 (03) ◽  
pp. 140-169
Author(s):  
Milton Martin
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Nonlinear Effects ◽  
Theoretical Method ◽  
Valuable Insight ◽  
Response Characteristics ◽  
Theoretical Predictions ◽  
Response Amplitude Operators ◽  
Phase Angles ◽  
Good Agreement

A theoretical method is derived for predicting the linearized response characteristics of constant deadrise high-speed planing boats in head and following waves. Comparisons of the theoretical predictions of the pitch and heave response amplitude operators and phase angles with existing experimental data show reasonably good agreement for a wide variety of conditions of interest. It appears that nonlinear effects are more severe at a speed to length ratio of 6 than of, say, 4 or less, principally because of the reduction of the damping ratio of the boat with increasing speed, and the consequent increase in motions in the vicinity of the resonant encounter frequency. However, it is concluded that the linear theory can provide a simple and fast means of determining the effect of various parameters such as trim angle, deadrise, loading, and speed on the damping, natural frequency, and linearized response in waves, and that this can furnish valuable insight into the actual boat dynamics, even though the accurate predictions of large motions and peak accelerations would require a nonlinear analysis.

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