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풍속측정
시스템
WIND
SPEED / BOUNDARY LAYER CONDUCTANCE (WS-01-ATX)
WS-01-ATX
Sensor for ultra low wind speeds and sensor
for leaf boundary layer conductance
WS-01-ATX is a sensor that is used to
investigate the heat transfer coefficient, Ctr, from its surface to
the air. The obtained data can be used to determine other transfer coefficients
(for instance for water vapour transport) or local wind speed (specifically in
the low wind speed range). Both measurements are qualitative rather than
absolute. WS-01-ATX is suitable for outdoor use. It has to be used in combination
with a proper data acquisition and control system.
 WS-01-ATX consists of a heater and a sensor
incorporated in a very thin plastic foil. The sensor in WS-01-ATX, consisting of two
thermopiles, performs a differential temperature measurement around the heating
wire with record breaking sensitivity.
When placing the sensor in air and switching
on the heater, the sensor output will be inversely proportional to the heat
transfer to the air.
The main application of WS-01-ATX is as an "artificial leaf" to
study mass transport in the leaf boundary layer. In this application it is a
benefit that WS-01-ATX has a leaf-like geometry (flat and thin).
Also WS-01-ATX can be
used to study local wind speed in the 0.1 to 2 m/s region, for instance in
greenhouses and buildings. This can only be done if there is one predominant
wind direction.
Measurement errors induced by solar
radiation are strongly reduced by the fact that the sensor is symmetrically
placed around the wire, and by using the technique of pulsed heating. The low
thermal mass makes WS-01-ATX very fast, reaching thermal equilibrium in 30 s in still
air.
When considering to apply WS-01-ATX it is
recommended to consult the manual which is available at LICHTZEN AE / AITNIX. A program for
interfacing with the Campbell Scientific CR10X and CR1000 are
available.
Figure 1.
WS-01-ATX
sensor: thermopiles (1), heating wire (2), cable (3). Dimensions in mm.
 Figure 2.
graphs
at different wind speeds: signal amplitude varies with 1/ wind speed or
1/Ctr
Suggested use
- As "artificial leaf" in scientific studies of leaf
boundary layer transport.
- As wind speed sensor and heat transfer coefficient
sensor in scientific studies at very low wind speeds.
WS-01-ATX sensor specifications
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Thermocouples: 40
Cu-CuNi
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Temperature range: -30 to +80
°C
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Sensor thickness (nominal): 0.15 mm
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Required readout: 2 diff
voltage channels 3 V and 5 mV range
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Voltage input: 1-2 VDC
(nominal)
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Interfacing: to most
common datalogging systems
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