DE102017120224A1 - FLOW PROBE - Google Patents

Abstract

A flow probe 10 is shown. The flow probe 10 comprises a probe head 16 with one or more openings which are connected by fluid lines to a sensor means and / or a sensor means arranged on a surface of the probe head 16. The flow probe 10 further comprises a probe shaft 18 and a connecting portion 20 connecting the probe head 16 to the probe shaft 18. The connecting portion 20 has an elongated cross-sectional outline with a tapered portion or the fluid conduits are arranged one behind the other in the connecting portion 20, whereby the passage through the Flow probe 10 is reduced flow resistance compared to conventional, cranked flow probes is reduced.

Description

TERRITORY

The present invention relates to a flow probe. In particular, the present invention relates to a flow sensor for flow measurement.

BACKGROUND

Flow probes are often used to detect fluid mechanical characteristics and typically have a probe head with, for example, one, three, five or seven openings, the openings via fluid lines with sensor means such. B. pressure sensors are connected. If the flow probe is introduced into a flow, a separate measured value or pressure value can be detected per opening, whereby, when using pressure sensors u. a. the flow velocity and in Mehrlochchsonden with pressure sensors additionally let the direction components of the flow relative to the probe head determine.

Combined probes for measuring pressure and temperature also have a temperature measuring point. Since undisturbed effluent is needed to accurately measure temperature at high flow rates, combined probes are typically cranked with the probe shaft extending perpendicular to the probe head axis. However, cranked probes often have unfavorable aerodynamic properties.

SUMMARY

The invention enriches in this regard the prior art, as inventive flow probes have improved aerodynamic properties, whereby both the use as a combined probe for pressure and temperature measurement and generally the use in scenarios in which probe head and probe shaft (for example, due to the test setup) can not be aligned coaxially, is made possible.

A flow probe according to the invention comprises a probe head with an opening which is connected or connectable by a fluid line to a sensor means and / or a sensor means arranged on a surface of the probe head. The flow probe further comprises a probe shaft and a connecting portion connecting the probe head to the probe shaft, the connecting portion having an elongate cross-sectional contour with a tapered portion.

The term "flow probe" as used in the description and the claims is to be understood in particular as a device which has a sensor means (for example a piezoelectric pressure sensor) arranged on the surface of the probe and / or an opening which the sensor means may be arranged both in the flow probe (eg integrated into the probe head) and outside the flow probe (eg the flow probe may have a port through which the fluid conduit communicates with the sensor) Sensor means is connectable). Further, the term "probe head" as used in the specification and claims is to be understood in particular as a probe section which extends in the proximal direction from the distal end of the flow probe.

Furthermore, the term "opening" as used in the description and the claims, in particular a recess in an otherwise flat or curved (wedge-shaped, pyramidal, cylindrical, conical, spherical, etc.) surface of the probe head to understand. Furthermore, the term "fluid line" as used in the description and the claims, in particular a conduit (eg, a channel, pipe, hose, etc.) to understand without significant cross-sectional shape change. In addition, the term "sensor means", as used in the description and the claims, in particular a device for measuring an environmental parameter (eg. Pressure, temperature, etc.) to understand.

Further, the term "probe shaft" as used in the specification and claims is to be understood in particular as a probe section which extends distally from the proximal end of the flow probe. Further, the term "connecting portion" as used in the specification and claims means, in particular, a probe portion having two ends, at one end of which the probe head is fixed and the other end of which is fixed to the probe shaft.

In addition, the phrase "elongated cross-sectional outline having a tapered portion" as used in the specification and claims means, in particular, a cross-sectional outline in which two (flat or domed) sides of the tapered portion converge in a peak. This may, for example, be the case when the connecting portion has two (flat or curved) side surfaces converging in one edge. It is understood that the tip / edge can be rounded for manufacturing or occupational safety reasons.

By having the connecting portion of elongate cross-sectional contour with a tapered portion, the flow resistance and flow impact created by the flow probe can be reduced as compared to conventional cranked flow probes of typically round cross-section. In particular, the tapered portion reduces the risk of vibratory vortex shedding.

Preferably, the probe head has a temperature measuring point and the connecting portion extends from an area of the probe head facing away from the temperature measuring point.

This enables the simultaneous measurement of pressure and temperature in the smallest of spaces.

The probe head preferably has an inflow surface which is rotationally symmetrical about an axis of symmetry and the probe shaft has a longitudinal axis, the axis of symmetry of the rotationally symmetrical inflow surface extending substantially parallel and offset relative to the longitudinal axis of the probe shaft.

By the term "substantially parallel" as used in the specification and claims is meant in particular a relative tilt of not more than 10 ° and preferably not more than 5 °.

As a result, the probe can be used on measurement structures which, due to their geometry, cause an axis of symmetry of the rotationally symmetrical inflow surface which runs essentially parallel to the longitudinal axis of the probe shaft.

Preferably, the tapered portion is mirror-symmetrical to a plane spanned by the axis of symmetry and the longitudinal axis.

As a result, a force acting on the probe transversely to this plane and the flow resistance can be reduced if the main flow direction is parallel thereto.

Preferably, a section through the flow probe along the said plane has a Z-shaped outline.

Thereby, a coaxial placement of the probe head and probe shaft can be avoided, whereby a simultaneous measurement of pressure and temperature without substantial mutual influence of both measuring points at measuring positions, which require a substantially parallel alignment of the probe head and probe shaft, is made possible.

The probe head preferably has an inflow surface which is rotationally symmetrical about an axis of symmetry and the connecting portion has a longitudinal axis, the axis of symmetry and the longitudinal axis enclosing an angle which is greater than 90 ° and preferably greater than 100 °.

By bending the connecting section (by more or less than 90 °), the current impact of the probe can be further reduced.

Preferably, the axis of symmetry and the longitudinal axis at an angle greater than 110 ° and less than 130 ° and preferably 120 °.

By bending the connecting section by 110 ° to 130 °, the current impact of the probe can be further reduced.

Preferably, the probe shaft has a rod-shaped portion.

Thereby, a low flow resistance and also the stability of the probe in all spatial directions can be ensured even when using a long shaft.

A flow probe according to the invention comprises a probe head having three openings, a probe shaft and a connecting portion connecting the probe head to the probe shaft, each of the three openings opening into a respective fluid conduit which extends through the connecting portion to the probe shaft, the three fluid conduits in the connecting portion one behind the other and preferably arranged stacked.

In this case, the term "consecutively" as used in the description and the claims, in particular in (expected) flow direction to understand sequentially.

This allows a slimming of the profile of the connecting portion and thus a reduction of the caused by the probe flow resistance.

An inventive method for measuring the pressure and temperature of a fluid flow comprises arranging a flow probe with a temperature measuring point in the fluid flow, the flow probe having a probe head having an axis of rotation about a symmetry axis rotational flow surface, a temperature measuring point and one or more openings, each by a Fluid line are connected to a sensor means and / or one or more arranged on a surface of the probe head / arranged sensor means comprises. The flow probe further comprises a probe shaft having a longitudinal axis substantially parallel to the flow and offset from the axis of symmetry of the leading edge, and a connecting portion connecting the probe head to the probe shaft and having an elongate cross-sectional outline with a flow-tapering portion.

It is understood that similar advantages are achieved by the method according to the invention, as described above in connection with the use of flow probes according to the invention. Further, it is to be understood that all features of preferred embodiments of the flow probes may also be features of preferred embodiments of the method, which relates to the use of flow probes according to the invention.

list of figures

• 1 eine schematische Seitenansicht einer beispielhaften Ausgestaltung einer erfindungsgemäßen Strömungssonde;
• 1a eine schematische Draufsicht auf eine beispielhafte Ausgestaltung einer Anströmfläche des Sondenkopfes der in 1 gezeigten Strömungssonde (in vergrößerter Darstellung);
• 1b einen schematischen Querschnitt einer beispielhaften Ausgestaltung des Verbindungsabschnitts der in 1 gezeigten Strömungssonde (in vergrößerter Darstellung);
• 1c eine schematische Ansicht der in 1 gezeigten Strömungssonde entgegen der Strömungsrichtung (in vergrößerter Darstellung);
• 2 eine erste Abwandlung der in 1 gezeigten Strömungssonde;
• 3 eine zweite Abwandlung der in 1 gezeigten Strömungssonde;
• 4a einen schematischen Querschnitt einer ersten Abwandlung des in 1b gezeigten Verbindungsabschnitts;
• 4b einen schematischen Querschnitt einer zweiten Abwandlung des in 1b gezeigten Verbindungsabschnitts;
• 4c einen schematischen Querschnitt einer dritten Abwandlung des in 1b gezeigten Verbindungsabschnitts;
• 5 eine dritte Abwandlung der in 1 gezeigten Strömungssonde;
• 6 eine Abwandlung der in 2 gezeigten Strömungssonde;
• 7 eine Abwandlung der in 3 gezeigten Strömungssonde;
• 8 eine Abwandlung der in 6 gezeigten Strömungssonde; und
• 9 einen beispielhaften Prozess zum Messen von Druck und Temperatur einer Fluidströmung zeigt.

The invention will be explained in more detail in the detailed description on the basis of exemplary embodiments, reference being made to drawings in which:

• 1 a schematic side view of an exemplary embodiment of a flow sensor according to the invention;
• 1a a schematic plan view of an exemplary embodiment of an inflow surface of the probe head of in 1 shown flow probe (in enlarged scale);
• 1b a schematic cross-section of an exemplary embodiment of the connecting portion of in 1 shown flow probe (in enlarged scale);
• 1c a schematic view of in 1 shown flow probe against the flow direction (in an enlarged view);
• 2 a first modification of the 1 shown flow probe;
• 3 a second modification of the in 1 shown flow probe;
• 4a a schematic cross section of a first modification of the in 1b shown connecting portion;
• 4b a schematic cross section of a second modification of the in 1b shown connecting portion;
• 4c a schematic cross section of a third modification of the in 1b shown connecting portion;
• 5 a third modification of the in 1 shown flow probe;
• 6 a modification of the in 2 shown flow probe;
• 7 a modification of the in 3 shown flow probe;
• 8th a modification of the in 6 shown flow probe; and
• 9 shows an exemplary process for measuring pressure and temperature of a fluid flow.

The same and functionally similar elements are indicated by the same reference numerals in the drawings. However, it should be understood that not all elements are necessarily shown in the drawings, and that the elements shown are not necessarily to scale.

DETAILED DESCRIPTION

1 shows a schematic side view of an exemplary embodiment of a flow sensor according to the invention 10 , How out 1a can be seen, which is a schematic plan view of the (openings 12 having) inflow surface 14 of the probe head 16 the in 1 shown flow probe 10 (in enlarged view), the in 1 shown flow probe 10 designed as a 5-hole probe. It is understood, however, that the flow probe 10 not only, as in 1a shown, as a 5-hole probe, but also as 1-, 2-, 3-, 4-, 6-, 7-, 8- or 9-hole probe (not shown) can be performed and depending on the purpose any number (and Arrangement) at openings 12 can have.

As in 1 shown includes the flow probe 10 a probe shaft 18 and one the proximal end of the probe head 16 with the distal end of the probe shaft 18 connecting connecting section 20 , How out 1b can be seen, which is a schematic cross section of an exemplary embodiment of the connecting portion 20 the in 1 shown flow probe 10 (In an enlarged view), the connecting portion 20 an elongated cross-sectional outline 22 with a tapered (here wedge-shaped) section 24 on.

The tapered section 24 is mirror symmetric to a through the tapered section 24 extending symmetry axis 26 parallel to the axis of symmetry 28 the rotationally symmetrical inflow surface 14 runs, with the section 24 in the flow direction 30 rejuvenated. It is understood that the probe head 16 instead of a rotationally symmetrical inflow surface 14 also a wedge-shaped or pyramidal inflow surface 14 could, wherein the axis of symmetry 26 the tapered section 24 then, for example, parallel to the longitudinal axis of a by the inflow 14 enclosed wedge-shaped or pyramidal body (not shown) could be aligned.

One of the flow direction 30 facing section of the cross-sectional outline 22 is streamlined, z. B. elliptical or semicircular, and is formed by a portion whose sides are substantially parallel to the axis of symmetry 28 the rotationally symmetrical inflow surface 14 run, with the tapered section 24 connected. This results in an axis of symmetry 26 (Mirror) symmetrical wing profile, which the risk of vibration excitation by vortex shedding at the connecting portion 20 reduced.

In addition, the connection section 20 by more than 90 ° (or by approx. 120 °) against the axis of symmetry 28 the rotationally symmetrical inflow surface 14 inclined, it being understood that (depending on the purpose) also smaller or larger inclinations of the connecting section 20 relative to the flow direction 30 can be realized. In this connection, it should be noted that the angle which two axes enclose with each other within the meaning of the present description and claims means any one of the four angles included by the axis sections. Thus, an angle of less than 90 ° between two axes also causes an angle of more than 90 °, etc.

As in 1 shown, the longitudinal axis run 32 of the rod-shaped probe shaft 18 and the axis of symmetry 28 the rotationally symmetrical inflow surface 14 approximately parallel and are transverse to the flow direction 30 staggered. How out 1c can be seen, which is a schematic view from the rear / against the flow direction of in 1 shown flow probe 10 (in enlarged view) shows the probe shaft 18 a (circular) circular cross-section and tapering towards the distal end (asymmetrically), while at the proximal end of the probe shaft 18 an adapter 34 is arranged with a square cross-section. It is understood, however, that the adapter 34 could also have a hexagonal or octagonal cross-section or a thread.

While thus the outer shape of the adapter 34 can be selected according to the required / desired mechanical attachment or horizontal orientation, includes the adapter 34 one connection each 36 for extending each of a fluid line and / or for transmitting electrical signals. Are the openings 12 eg via fluid lines 42 with in the probe head 16 connected sensor means and generates a sensor means electrical signals, from which the measured by the sensor means measured value, for example. A pressure value can be determined, the electrical signals via one of the sensor means through the connecting portion 20 and the probe shaft 18 to the connection 36 guided electrical connection 40 be read out. In this case, a separate electrical line can be provided for each sensor means.

It is further understood that instead of or in addition to the openings 12 Sensor means (eg piezoelectric sensors) directly on the surface of the probe head 16 may be arranged, said sensor means in each case via one of the sensor means by the connecting portion 20 and the probe shaft 18 to the connection 36 guided electrical connection 40 can be read out. In an alternative embodiment, a wireless reading of the sensor means is conceivable.

In addition, the probe head 16 also a temperature measuring point 38 include. As in 1 shown, the temperature measuring point 38 at a proximal end of the probe head 16 be arranged in a region of the connecting portion 20 is facing away or opposite. The temperature measuring point 38 may include a nacelle within which there is a sensor means for measuring the temperature. The nacelle allows the dependence of the measured temperature value on the flow direction 30 which is advantageous in particular at high flow velocities (for example when using a "keel probe"). How out 1c As can be seen, the nacelle can be parallel to the axis of symmetry 28 the rotationally symmetrical inflow surface 14 have round cross-section. Like the ones in the probe head 16 arranged sensor means, the sensor means for measuring the temperature further via one of the temperature measuring point 38 through the connecting section 20 and the probe shaft 18 to the connection 36 (or to a separate connection) guided electrical line can be read or operated.

2 shows a first modification of the in 1 shown flow probe 10 which differ from the in 1 shown flow probe 10 characterized in that the distal end of the connecting portion 20 relative to the proximal end of the connecting portion 20 not in the flow direction 30 is offset, but contrary to the flow direction 30 ,

3 shows a second modification of the in 1 shown flow probe 10 which differ from the in 1 shown flow probe 10 characterized in that the connecting portion 20 (substantially) perpendicular to the flow direction 30 runs.

4a shows a schematic cross section of a first modification of the in 1b shown connection section 20 , Here is the tapered section 24 from the rest of the connection section 20 detachably formed, wherein the side surfaces of the section whose sides are substantially parallel to the flow 30 run, part of the tapered section 24 spread. In the 4a shown two-part design is to simplify the manufacturing process and allows access to the through the connecting portion 20 guided electrical connection 40 ,

4b shows a schematic cross section of a second modification of the in 1b shown connection section 20 , Here are next to the through the connection section 20 guided electrical connection 40 several (in the flow direction 30 seen) arranged one behind the other fluid lines 42 through the connecting section 20 guided. For example. The sensor means can be used to measure the pressure rather than in the probe head 16 , in the probe shaft 18 or outside the flow probe 10 be arranged, wherein the sensor means for measuring the pressure (eg. Via connections in the adapter 34 ) with from the probe head 16 through the connecting section 20 to the probe shaft 18 extending fluid lines 42 are connected.

Because the axes of the fluid lines 42 (in the connecting section 20 ) lie in a plane, the connection section 20 in relation to the size of the fluid lines 42 be kept particularly narrow. It is also understood that the fluid lines 42 instead of having a round cross-section, it may also have a polygonal cross-section or another (arbitrary) cross-sectional shape. Furthermore, the electrical connection 40 also outside the connection section 20 are guided along the trailing edge.

4c shows a schematic cross section of a third modification of the in 1b shown connection section 20 , They are in the flow direction 30 successively arranged fluid lines 42 Stacked offset to each other, whereby a larger diameter of the fluid lines 42 is achieved. It is understood that the fluid lines 42 in the in 4b and 4c Variations shown may be formed both as hoses or tubes in a sleeve-like or (eg. As in 4a shown) two-part connecting portion 20 are introduced, as well as in the material of the connecting portion 20 milled or drilled. For example. can the connection section 20 divided along its plane of symmetry in half, in their joining the fluid lines 42 be formed. Furthermore, the probe head 16 , the connection section 20 and / or the probe shaft 18 by means of an additive manufacturing process z. B. by metal laser sintering ("3D metal printing") are generated.

5 shows a third modification of the in 1 shown flow probe 10 which differ from the in 1 shown flow probe 10 this distinguishes that of the probe shaft 18 shortened running and the adapter 34 at the side of the probe shaft 18 is arranged. This allows replacement of cranked probes (not shown) against those in Figs 5 shown flow probe 10 without having to modify the measurement setup, as well as using the flow probe 10 in scenarios in which only a lateral attachment is possible.

6 shows a modification of the in 2 shown flow probe 10 which differ from the in 2 shown flow probe 10 analogous to 5 this distinguishes that of the probe shaft 18 shortened running and the adapter 34 at the side of the probe shaft 18 is arranged. This also allows the in 6 shown flow probe 10 to be replaced with cranked probes (not shown) without having to modify the measurement setup. In addition, there is also a use of the flow probe 10 in scenarios in which only a lateral attachment is possible, given.

7 shows a modification of the in 3 shown flow probe 10 which differ from the in 3 shown flow probe 10 this distinguishes that of the probe shaft 18 shortened running and the function of the adapter 34 already in the probe shaft 18 is integrated. As related to 5 and 6 cited, the in 7 shown flow probe 10 to be replaced with cranked probes (not shown) without having to modify the measurement setup. In addition, there is also a use of the flow probe 10 in scenarios in which only a lateral attachment is possible, given.

8th shows a modification of the in 6 shown flow probe 10 which differ from the in 6 shown flow probe 10 this distinguishes that probe shaft 18 , Connecting section 20 and probe head 16 have a sickle-like profile in side view (also referred to as a hook or cobra probe) and on the temperature measuring point 38 was waived. For example. can the in 8th shown flow probe 10 be executed as Prandtl probe.

9 shows an exemplary process for measuring pressure and temperature of a fluid flow. The process begins with the step 46 arranging the flow probe 10 in the fluid flow. For example. can the flow probe 10 by means of the adapter 34 (or the probe shaft 18 ) are fixed in a measuring structure (eg within a wind tunnel for measuring a flow profile, not shown) in such a way that the axis of symmetry 28 the rotationally symmetrical inflow surface 14 approximately parallel to the expected main flow direction 30 is. For example, a flow profile within a wind tunnel can be measured

Before placing the flow probe 10 in the measuring point can in step 44 a speed and, in particular in the case of multiple sensor means, a directional calibration can be performed. In addition, the calibration (in the presence of a temperature measuring point 38 ) also comprise calibrating the sensor means for measuring the temperature. After that, in step 48 at the same time pressure and temperature values of the flow are determined, for example by a computer via the connection 36 Connected to the sensor means or connected to the computer sensor means to the fluid lines 42 be connected.

From the determined pressure values, a characterization of the flow can then be carried out using the previously performed calibration. This can for example take place on the output side of a lattice wind tunnel for measuring the wake of a blade in a linear cascade. It is also conceivable to use a probe according to the invention, for example on or within a turbomachine, in order to determine flow variables even in places which are difficult to access and to influence the flow itself as little as possible.

With pneumatic measuring technology (and stationary flow state), time averaged flow data can be used. In addition, the flow probe 10 also be traversed to obtain a "spatial" velocity profile at steady state flow. If time-varying flow data is to be detected, piezoelectric pressure sensors may be provided on the surface of the probe head, as stated above 16 be used.

The flow probes described above with reference to the drawings 10 include a probe head 16 with one or more openings 12 passing through fluid lines 42 connected to a sensor means, and / or one or more on the surface of the probe head 16 arranged / arranged sensor means. Furthermore, the flow probes include 10 a probe shaft 18 and one the probe head 16 with the probe shaft 18 connecting connecting section 20 ,

The connecting section 20 has an elongated cross-sectional outline 22 with a tapered section 24 on or the fluid lines 42 are in the connection section 20 (in the flow direction 30 ) arranged one behind the other, thereby passing through the flow probe 10 flow resistance produced is reduced as compared to conventional cranked flow probes (not shown).

In addition, the probe head 16 , the connection section 20 and the probe shaft 18 in the embodiments of 1 to 7 be designed as mutually releasable components, so that they are each individually interchangeable with one or more of the modified components shown in the figures. Thus, as needed, each probe head 16 with each connection section 20 and every probe shaft 18 combined, resulting in the variability and cost-effectiveness of the flow probes shown 10 elevated.

LIST OF REFERENCE NUMBERS

10

flow probe

12

opening

14

inflow area

16

probe head

18

probe shaft

20

connecting portion

22

Cross-section outline

24

Rejuvenating section

26

axis of symmetry

28

axis of symmetry

30

flow direction

32

longitudinal axis

34

adapter

36

connection

38

Temperature measuring point

40

electrical connection

42

fluid line

44

process step

46

process step

48

process step

Claims (10)

A flow probe (10) comprising: a probe head (16) having: an opening (12) connected or connectable by a fluid conduit (42) to a sensor means and / or a sensor means disposed on a surface of the probe head (16); a probe shaft (18); and a connecting portion (20) connecting the probe head (16) to the probe shaft (18); wherein the connecting portion (20) has an elongated cross-sectional contour (22) with a tapered portion (24). Flow probe (10) after Claim 1 wherein the probe head (16) has a temperature measuring point (38) and the connecting portion (20) extends from an area of the probe head (16) remote from the temperature measuring point (38). Flow probe (10) after Claim 1 or 2 , wherein the probe head (16) has a longitudinal axis (32) about an axis of symmetry (28) rotationally symmetrical inflow surface (14) and the probe shaft (18), wherein the axis of symmetry (28) of the rotationally symmetrical inflow surface (14) substantially parallel and offset from Longitudinal axis (32) of the probe shaft (18) extends. Flow probe (10) after Claim 3 wherein the tapered portion (24) is mirror symmetrical to a plane defined by the axis of symmetry (28) and the longitudinal axis (32). Flow probe (10) after Claim 4 wherein a section through the flow probe (10) along the said plane has a Z-shaped outline. Flow probe (10) according to one of Claims 1 to 5 in which the probe head (16) has an inflow surface (14) rotationally symmetrical about an axis of symmetry (28) and the connecting portion (20) has a longitudinal axis, wherein the axis of symmetry (28) and the longitudinal axis enclose an angle greater than 90 ° and preferably greater than 100 °. Flow probe (10) after Claim 6 wherein the axis of symmetry (28) and the longitudinal axis enclose with each other an angle which is greater than 110 ° and less than 130 ° and preferably 120 °. Flow probe (10) according to one of Claims 1 to 7 wherein the probe shaft (18) has a rod-shaped portion. A flow probe (10) comprising: a probe head (16) having three openings (12); a probe shaft (18); and a connecting portion (20) connecting the probe head (16) to the probe shaft (18); wherein each of the three openings (12) opens into a respective fluid line (42) which extends through the connecting portion (20) to the probe shaft (18); wherein the three fluid conduits (42) are arranged in the connecting section (20) behind one another and preferably stacked. A method of measuring pressure and temperature of a fluid flow, comprising: Arranging (46) a flow probe (10) with a temperature measuring point (38) in the fluid flow; wherein the flow probe (10): a probe head (16) having a about an axis of symmetry (28) rotationally symmetrical inflow surface (14), a temperature measuring point (38), and one or more openings (12) which are each connected by a fluid line (42) to a sensor means, and / or one or more sensor means disposed on a surface of the probe head (16) includes; a probe shaft (18) having a longitudinal axis (32) which is aligned substantially parallel to the flow and offset from the axis of symmetry (28) of the inflow surface (14); and a connecting portion (20) connecting the probe head (16) to the probe shaft (18) and having an elongate cross-sectional contour (22) with a portion (24) tapering in the flow direction (30).

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