Abstract
In regions subjected to a cold climate, wind turbines and other exposed structures are vulnerable to the deposition of ice, which may reduce the performance and constitute a danger for the structure itself as well as for the surroundings. These problems increase with the taller structures that follow with e.g. larger wind turbines. During several years the company HoloOptics has been engaged in the development of a sensor for measuring the rate of ice deposition on structures. This report covers the calibration of the sensor, which has been carried out in the icing wind tunnel of VTT in Esbo, Finland. The icing sensor is based on an optical method. The optical properties of any surface change when covered by ice, regardless of type. When using the sensor for measuring the icing rate, the measurement surface is de-iced electrically as soon as ice has been detected. When the surface is observed to be free of ice, the de-icing is cut off. If icing conditions are still prevalent, after a while ice will again be detected on the surface, and the deicing cycle starts once more. By studying how often these cycles are repeated during a certain time span, the icing rate
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Westerlund, Rolf
[1]
- HoloOptics, Stockholm (Sweden)
Citation Formats
Westerlund, Rolf.
Calibration of sensor for measurement of ice growth; Kalibrering av givare som maeter istillvaext.
Sweden: N. p.,
2010.
Web.
Westerlund, Rolf.
Calibration of sensor for measurement of ice growth; Kalibrering av givare som maeter istillvaext.
Sweden.
Westerlund, Rolf.
2010.
"Calibration of sensor for measurement of ice growth; Kalibrering av givare som maeter istillvaext."
Sweden.
@misc{etde_1004733,
title = {Calibration of sensor for measurement of ice growth; Kalibrering av givare som maeter istillvaext}
author = {Westerlund, Rolf}
abstractNote = {In regions subjected to a cold climate, wind turbines and other exposed structures are vulnerable to the deposition of ice, which may reduce the performance and constitute a danger for the structure itself as well as for the surroundings. These problems increase with the taller structures that follow with e.g. larger wind turbines. During several years the company HoloOptics has been engaged in the development of a sensor for measuring the rate of ice deposition on structures. This report covers the calibration of the sensor, which has been carried out in the icing wind tunnel of VTT in Esbo, Finland. The icing sensor is based on an optical method. The optical properties of any surface change when covered by ice, regardless of type. When using the sensor for measuring the icing rate, the measurement surface is de-iced electrically as soon as ice has been detected. When the surface is observed to be free of ice, the de-icing is cut off. If icing conditions are still prevalent, after a while ice will again be detected on the surface, and the deicing cycle starts once more. By studying how often these cycles are repeated during a certain time span, the icing rate can be calculated. During the tests in the icing wind tunnel the sensor was calibrated by comparison with the measured icing of a 30 mm diameter reference cylinder. The calibration revealed that the sensor is very sensitive when exposed to light icing up to 20 g/m,h. In the interval 20-140 g/m,h the sensor is less sensitive. Above 140 g/m,h the sensor is saturated and the reading constant. The preferred method is to record the number of indications during a fixed period of time. Variation of the direction of the wind does not influence the result by more than 8-10 %}
place = {Sweden}
year = {2010}
month = {Oct}
}
title = {Calibration of sensor for measurement of ice growth; Kalibrering av givare som maeter istillvaext}
author = {Westerlund, Rolf}
abstractNote = {In regions subjected to a cold climate, wind turbines and other exposed structures are vulnerable to the deposition of ice, which may reduce the performance and constitute a danger for the structure itself as well as for the surroundings. These problems increase with the taller structures that follow with e.g. larger wind turbines. During several years the company HoloOptics has been engaged in the development of a sensor for measuring the rate of ice deposition on structures. This report covers the calibration of the sensor, which has been carried out in the icing wind tunnel of VTT in Esbo, Finland. The icing sensor is based on an optical method. The optical properties of any surface change when covered by ice, regardless of type. When using the sensor for measuring the icing rate, the measurement surface is de-iced electrically as soon as ice has been detected. When the surface is observed to be free of ice, the de-icing is cut off. If icing conditions are still prevalent, after a while ice will again be detected on the surface, and the deicing cycle starts once more. By studying how often these cycles are repeated during a certain time span, the icing rate can be calculated. During the tests in the icing wind tunnel the sensor was calibrated by comparison with the measured icing of a 30 mm diameter reference cylinder. The calibration revealed that the sensor is very sensitive when exposed to light icing up to 20 g/m,h. In the interval 20-140 g/m,h the sensor is less sensitive. Above 140 g/m,h the sensor is saturated and the reading constant. The preferred method is to record the number of indications during a fixed period of time. Variation of the direction of the wind does not influence the result by more than 8-10 %}
place = {Sweden}
year = {2010}
month = {Oct}
}