In situ estimation of effective liquid water content on a wind turbine using a thermal based sensor

2021 ◽  
Vol 184 ◽  
pp. 103235
Author(s):  
Patrice Roberge ◽  
Jean Lemay ◽  
Jean Ruel ◽  
André Bégin-Drolet
Keyword(s):  
Wind Turbine ◽  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content

In situ ground based measurements of low level clouds during 10 years of Pallas cloud experiments.

2020 ◽  
Author(s):  
Konstantinos Doulgeris ◽  
David Brus
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Meteorological Data ◽  
Liquid Water Content ◽  
Data Set ◽  
Radiative Balance ◽  
Low Level ◽  
Major Factors

<p>Clouds and their interaction with aerosols are considered one of the major factors that are connected with uncertainties in predictions of climate change and are highly associated with earth radiative balance. Semi long term in-situ measurements of Arctic low-level clouds have been conducted during last 10 year (2009 - 2019) autumns at Sammaltunturi station (67◦58´N, 24◦07´E, and 560 m a.s.l.), the part of Pallas Atmosphere - Ecosystem Supersite and Global Atmosphere Watch (GAW) programme. During these years a unique data set of continuous and detailed ground-based cloud observations over the sub-Arctic area was obtained. The in-situ cloud measurements were made using two cloud probes that were installed on the roof of the station: the Cloud, Aerosol and Precipitation Spectrometer probe (CAPS) and the Forward Scattering Spectrometer Probe<strong> (</strong>FSSP<strong>)</strong>, both made by droplet measurement technologies (DMT, Longmont, CO, USA). CAPS in­cludes three instruments: the Cloud Imaging Probe (CIP, 12.5 μm-1.55 mm), the Cloud and Aerosol Spectrometer (CAS-DPOL, 0.51-50 μm) with depolarization feature and the Hotwire Liquid Water Content Sensor (Hotwire LWC, 0 - 3 g/m<sup>3</sup>). Vaisala FD12P weather sensor was used to measure all the meteorological data. The essential cloud microphysical parameters we investigated during this work were the size distributions, the total number concentrations, the effective radius of cloud droplets and the cloud liquid water content. The year to year comparison and correlations among semi long term in situ cloud measurements and meteorology are presented.</p>

scholarly journals Effect of liquid water content on blade icing shape of horizontal axis wind turbine by numerical simulation

2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1637-1645
Author(s):  
Yan Li ◽  
Ce Sun ◽  
Yu Jiang ◽  
Xian Yi ◽  
Yingwei Zhang
Keyword(s):  
Wind Turbine ◽  
Water Content ◽  
Liquid Water ◽  
Large Scale ◽  
Liquid Water Content ◽  
Horizontal Axis ◽  
Computation Method ◽  
Layer By Layer ◽  
Horizontal Axis Wind Turbine ◽  
Blade Tip

To research the law of the icing accretes on near the tip part of rotating blade of large-scale horizontal axis wind turbine (HAWT) influenced by liquid water content (LWC), the icing distribution on a HAWT rotor with rated power of 1.5 MW was simulated based on a Quasi-3D computation method. About 30% part length of blade from tip along span wise to blade root which are the most serious icing area was selected to research. Eight sections of this 30% part were decided and the ice distribution on each sections were simulated. Five kinds of LWC from 0.2 g/m3 to 1.4 g/m3 and two kinds of temperatures including ?6?C and ?18?C were selected. The medium volume droplet is 30 mm. Three kinds of icing time were selected to analyze the effects of icing time on ice accretion. The icing shape evaluate method was applied to quantitatively analyze the icing shape obtatined under different conditions. The results show that the icing shapes are all horn icing shape under the different LWC when the temperature is ?6?C. The icing shapes change from horn icing shape to streamline icing shape with LWC increasing under the temperature of ?18?C. The icing accretes on blade surface layer by layer with icing time increasing. The closer the section blade tip, the more icing accretes. This study can be as reference for the research on anti-icing and de-icing technologies for large-scale HAWT.

In situ measurements of liquid water content profiles in midlatitude stratiform clouds

2007 ◽  
Vol 133 (628) ◽  
pp. 1693-1699 ◽  
Author(s):  
A. V. Korolev ◽  
G. A. Isaac ◽  
J. W. Strapp ◽  
S. G. Cober ◽  
H. W. Barker
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content ◽  
In Situ Measurements ◽  
Stratiform Clouds

scholarly journals Characterizing and Predicting Marine Fog Offshore Newfoundland and Labrador

2020 ◽  
Vol 35 (2) ◽  
pp. 347-365 ◽  
Author(s):  
George A. Isaac ◽  
Terry Bullock ◽  
Jennifer Beale ◽  
Steven Beale
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Newfoundland And Labrador ◽  
Liquid Water Content ◽  
Time Frame ◽  
Microphysical Properties ◽  
Droplet Concentration ◽  
Air Temperatures ◽  
Summer Time

Abstract As several review papers have concluded, marine fog is imperfectly characterized, and quantitative visibility forecasts are difficult to produce accurately. Some unique measurements have been made offshore Newfoundland and Labrador of the climatology of occurrence and the microphysical characteristics of marine, or open-ocean, fog. Based on measurements made at an offshore installation over 21 years, the percent of time with visibilities less than 0.5 n mi or approximately 1 km (1 n mi ≈ 1.85 km) reaches 45% in July, with a low of about 5% during the winter. The occurrence of fog is mainly due to warm air advection, with the highest frequency occurring with wind directions from over the warm Gulf Stream, and with air temperatures about 2°C warmer than the sea surface temperature. There is no diurnal variation in the frequency of occurrence of fog. The microphysical properties of the fog have been documented in the summer time frame, with over 550 h of in situ measurements made offshore with fog liquid water content greater than 0.005 g m−3. The fog droplet number concentration spectra peaks near 6 μm, with a secondary peak near 25–40 μm, which typically contains most of the liquid water content. The median droplet concentration is approximately 70–100 cm−3. The microphysical spectra have been used to develop a new NWP visibility parameterization scheme, and this scheme is compared with other parameterizations currently in use.

scholarly journals In-situ cloud ground based measurements in Finnish sub-Arctic: Intercomparison of three cloud spectrometers

2020 ◽  
Author(s):  
Konstantinos-Matthaios Doulgeris ◽  
Mika Komppula ◽  
Sami Romakkaniemi ◽  
Antti-Pekka Hyvärinen ◽  
Veli-Matti Kerminen ◽  
...  
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Wind Direction ◽  
Liquid Water Content ◽  
Measured Parameter ◽  
Effective Diameter ◽  
Rotating Platform ◽  
Cloud Droplets ◽  
Median Volume

Abstract. Continuous, semi-long term, ground based, in-situ cloud measurements were conducted during the Pallas Cloud Experiment (PaCE) in 2013. The measurements were carried out in Finnish sub-Arctic region at Sammaltunturi station (67°58'N, 24°07'E, and 560 m a.s.l.), the part of Pallas Atmosphere – Ecosystem Supersite and Global Atmosphere Watch (GAW) programme. The main motivation of the campaign was to conduct in-situ cloud measurements with three different cloud spectrometer probes and perform an evaluation of their ground based setups. Therefore, we mutually compared the performance of the Cloud and Aerosol Spectrometer (CAS), the Cloud Droplet Probe (CDP) and the Forward Scattering Spectrometer Probe (FSSP-100), (DMT, Boulder, CO, USA). We investigated how different meteorological parameters affect each instrument operation and quantified possible biases and discrepancies of different microphysical cloud properties. Based on obtained results we suggested limitations for further use of the instruments in campaigns where focus is on investigating aerosol cloud interactions. Measurements in this study were made by Finnish Meteorological Institute owned instruments and results concern their operation in sub-Arctic conditions with frequently occurring super-cooled clouds. Measured parameter from each instrument was the size distribution and additionally we derived the number concentration, the effective diameter, the median volume diameter and the liquid water content. A complete intercomparison between the CAS probe and the FSSP-100 and additionally between the FSSP-100 and the CDP probe was made and presented. Unfortunately, there was not sufficient amount of common data to compare all three probes together due to operational problems of the CDP ground setup in sub-zero conditions. The CAS probe that was fixed to one direction lost significant number of cloud droplets when the wind direction was out of wind iso axial conditions in comparison with the FSSP-100 and the CDP which were both placed on a rotating platform. We revealed that CAS and FSSP-100 had good agreement in deriving sizing parameters (effective diameter and median volume diameter from 5 to 35 µm) even though CAS was losing a significant amount of cloud droplets. The most sensitive derived parameter was liquid water content which was strongly connected to the wind direction and temperature.

Transient atmospheric ice accretion on wind turbine blades

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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