United Sensor 3 Dimensional Directional probes measure yaw and pitch angles of fluid flow, as well as total and static pressures and total temperature.

Each probe has five measuring holes located on its tip. A centrally located pressure hole measures pressure P1, while two lateral pressure holes measure pressures P2 and P3. If the probe is rotated by a Traverse Unit (Fig. 1) until P2 = P3 as indicated on a manometer or other sensitive pressure indicator, the yaw angle of flow is then indicated by the traverse unit scale (see Manual Traverse Unit catalog pages).

When the yaw angle has been determined an additional differential pressure P4 - P5 is measured by pressure holes located above and below the total pressure (P1) hole. Pitch angle is determined by calculating (P4 - P5)/ (P1 - P2) and using the calibration curve for the individual probe (e.g. Curve A, Figs. 2 and 3). At any particular pitch angle the velocity pressure coefficient (Pt - Ps)/ (P1 - P2) and total pressure coefficient (P1 - Pt)/ (Pt - Ps) can be read from curves B and C, while Pt - Ps and Ps can be calculated. In the case of Type DAT probes, a half shielded thermocouple sensor at the probe tip provides total temperature measurements at the same point in the stream as fluid pressure and flow direction measurements.

 
Fig 1. Typical manometer connections for DA or DC probes.
Fig 2. Typical calibration of DA probe versus pitch angle.
Fig 3. Typical calibration of DC probe versus pitch angle.



Standard Specifications:

DA: Five hole prism shaped measuring section. Measures total and static pressure, yaw angle and pitch angle. Furnished with individual calibration curves up to pitch angles of 40? Tip extends 2 diameters beyond holes. Typical calibration shown in Fig. 4. Smallest size can be inserted through 1/8" hole. Usable up to Mach .07. Standard diameters are 1/8", 3/16", 1/4", 3/8", 1.00"
DAT: Five holes plus thermocouple. Measures total and static pressure, yaw angle, pitch angle and total temperature. Furnished with individual calibration curves up to pitch angles of 40? Tip extends 3.5 diameters beyond holes. Standard diameters are: 3/16", 1/4", 3/8", 1.00"
DC:Five hole conical shaped measuring section. Measures total and static pressure, yaw angle, and pitch angle. More suitable for use near boundaries than type DA. Furnished with individual calibration curves up to pitch angles of 40? Usable up to Mach 0.7. DC-120 head fits through a clearance hole .62" diameter. Typical calibration curve illustrated in Fig. 4. Standard diameters are: 3/32", 1/8", 3/16", 1/4"



Ordering Information




Typical Example: DAT-187-24-F-22-CD-K-Plug

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