Description
Fiber-film probes have cylindrical thin film sensors and may be used as a substitute for wire probes in liquids or in gas applications where more robust probes are needed. They are considerably more rugged than wire probes and less sensitive to contamination. Fiber sensors are 70 µm diameter quartz fibers, 3 mm long, covered by a nickel thin film approx. 0.1 µm in thickness.
The sensors are arranged in X-arrays, where they form an angle of 90° with one another. The probe body is a 2.3 mm diameter ceramic tube, equipped with gold-plated connector pins that connect to the probe supports by means of plug-and-socket arrangements. Dual-sensor probes have marks (one and two dots) that indicate the sensor number. Fiber probes are, furthermore, marked with symbols indicating applications in gas or liquids (red dot = air, blue dot = water).
All X-probes measure two velocity components simultaneously in turbulent, instationary two-dimensional flow fields. They provide information for calculation of Reynolds shear stress. The flow vector may not exceed ±45°.
Configurations
Dual-sensor fiber-film probes are available in the following four configurations, with either a thin or a heavy coating. The picture on the right shows the dimensions common for the probes.
Mounting: 6 mm dia. probe supports.
Fiber-film X-probe, straight (55R51 and 55R61)
X-probe with straight prongs and with the sensor plane parallel to probe axis. Probe 55R51 has a thin coating (0.5 µm) and probe 55R61 has a heavy coating (2 µm).
This probe is used in free-stream applications. Mounts with the probe axis parallel to the direction of main flow, so that the predominant flow vector attacks the two wires under 45°.
Buy at Dantec Dynamics’ Shop (thin coating)
Buy at Dantec Dynamics’ Shop (heavy coating)
Fiber-film X-probe, cross flow (55R52 and 55R62)
X-probe with straight prongs and with the sensor plane perpendicular to probe axis, for radial operation. Probe 55R52 has a thin coating (0.5 µm) and probe 55R62 has a heavy coating (2 µm).
Used in places not readily accessible, for example in pipes. Mounts with the probe axis perpendicular to the main flow and with the predominant flow vector 45° to the two wires.
Buy at Dantec Dynamics’ Shop (thin coating)
Buy at Dantec Dynamics’ Shop (heavy coating)
Fiber-film X-probe, right angle, parallel (55R53 and 55R63)
X-probe with right-angled prongs and with the sensor plan parallel to probe axis. Probe 55R53 has a thin coating (0.5 µm) and probe 55R63 has a heavy coating (2 µm).
Intended for radial operation in pipes or ducts. This probe measure the U-V components. Mounts with the probe axis perpendicular to the main flow and rotated, so that the predominant flow vector attacks the two wires under 45°.
Buy at Dantec Dynamics’ Shop (thin coating)
Buy at Dantec Dynamics’ Shop (heavy coating)
Fiber-film X-probe, right angle, perpendicular (55R54 and 55R64)
X-probe with right-angled prongs and with the sensor plan perpendicular to probe axis. Probe 55R54 has a thin coating (0.5 µm) and probe 55R64 has a heavy coating (2 µm).
Intended for radial operation in pipes or ducts. This probe measure the U-W components. Mounts with the probe axis perpendicular to the main flow and rotated, so that the predominant flow vector attacks the two wires under 45°.
Buy at Dantec Dynamics’ Shop (thin coating)
Buy at Dantec Dynamics’ Shop (heavy coating)
| Technical Data For Fiber-film Sensors | ||
|---|---|---|
| Thickness of quartz coating | 0.5 µm | 2 µm |
| Medium | Air | Water |
| Sensor material | Nickel | |
| Sensor dimensions | 70 µm dia, 1.25 mm long The overall fiber lenght is 3 mm |
|
| Sensor resistance R20 (approx.) | 6 Ω | |
| Temperature coefficient of resistance (TCR) α 20 (approx.) | 0.40%/°C | |
| Max. sensor temperature | 300°C | 60°C 1),2) |
| Max. ambient temperature | 150°C | 100°C |
| Min. velocity | 0.05 m/s 3) | 0.01 m/s |
| Max. velocity | 350 m/s | 10 m/s |
| Frequency limit fmax (CTA mode) | 175 kHz | 30 kHz |
Notes
- At atmospheric pressure (1 bar)
- Max. 150°C at elevated pressure. Avoid bubble formation.
- Influence from natural convection up to approx. 0.20 m/s.
