Format:
v, 42 Seiten
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Illustrationen
Series Statement:
CRREL Report 77-17
Content:
A literature search was made for information on the accretion of ice on ocean structures and on methods for control. The bulk of the reports were in Russian, with some additional Japanese, British, American, Canadian, and Icelandic sources. Analysis of icing reports indicated that sea spray is the most important cause of ship icing, with lesser amounts due to freezing rain, snow, and fog. Icing is a potential danger whenever air temperatures are below the freezing point of water and the sea temperature is 6 C or lower. Theoretical work on the ice accretion process is discussed, and a method is suggested, based on Russian experiments, for calculating the sea spray accumulation rate for cylindrical and flat surfaces as a function of water source temperature, air temperature, and wind speed. Other factors that influence icing severity are ship size and configuration, angle between ship course and water heading, and ship speed. Icing in the north temperate latitudes generally occurs in the rear of barometric depressions. Maps showing limits of various degrees of icing severity are included. Atmospheric icing measurements on tall land-based structures are presented, and potential maximum accumulations estimated. Control measures are discussed, though no completely effective method is available. Mechanical (impaction) methods are the most common, but experiments have been conducted on heated, icephobic, and deformable surfaces, and with freezing point depressants. No device for the unequivocal measurement of ice accumulation is available, though some experimental methods are suitable for controlled testing; it is recommended that a device be developed.
Note:
MAB0014.001: ZSP-201-77/17
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CONTENTS
Abstract
Preface
Conversion factors: U.S. customary to metric units of measurements
Introduction
The freezing proeess
Icing observations
Geographical distribution of icing and contributing meteorological conditions
Extreme icing conditions
Extremes of icc accumulation
Prediction of icing occurrences
Prediction of icing intensity and rate
Control methods
Measurement of icing rate
Conclusions and recommendations
Literature cited
Appendix A. Maps of icing occurrence and rate
Appendix B. Data for computing ship icing rates
Appendix C. Estimation of ice accumulation
In:
CRREL Report, 77-17
Language:
English
Keywords:
Forschungsbericht
URL:
https://hdl.handle.net/11681/9516
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