The paper reports on the results from an experimental investigation of the response of multi-hole and hot wire probes at high flow Reynolds numbers (Re approx. 10(exp 6)). The limited results available in literature for 5-hole probes are restricted to Re approx. 10(exp 4). The experiment aims to investigate the probe response (in terms of dimensionless pressure ratios, characterizing pitch, and yaw angles and the total and static pressures) at high Re values and to gauge their effect on the calculated velocity vector. Hot wire calibrations were also undertaken with a parametric variation of the flow pressure, velocity and temperature. Different correction and calibration schemes are sought to be tested against the acquired data set. The data is in the analysis stage at the present time. The test provided good benchmark quality data that can be used to test future calibration and testing methods

Gerry, G.

Kauffman, W.

Ramachandran, N.

Smith, A.

English

NASA Technical Reports Server

NASA-CR-202052
HIGH REYNOLDS NUMBER EFFECTS ON MULTI-HOLE PROBES/./,#j'_- _ "
AND HOT WIRE ANEMOMETERS /,4/-3s-cA-
N. Ramachandran +, A. Smith', G. Gerry" and W. Kauffman"
+UniversitiesSpace Research Association
*NASA, Marshall Space Flight Center
/
Huntsville, Alabama 35812
ABSTRACT
The paper reports on the results from an experimental investigation of the response of
multi-hole and hot wire probes at high flow Reynolds numbers (Re ~ 106). The limited results
available in literature [1-3] for 5-hole probes are restricted to Re ~ 104. The experiment aims to
investigate the probe response (ih terms of dimensionless pressure ratios, characterizing pitch,
and yaw angles and the total and static pressures) at high Re values and to gauge their effect on
the calculated velocity vector. Hot wire calibrations were also undertaken with a parametric
variation of the flow pressure, velocity and temperature. Different correction and calibration
schemes are sought to be tested against the acquired data set. The data is in the analysis stage
at the present time. The test provided good benchmark quality data that can be used to test
future calibration and testing methods.
INTRODUCTION
Multi-hole probes like 3-hole and 5-hole probes are routinely used in air and water flow
testing to determine flow angularity and velocity. The design of these probes stems from the
classical pitot and pitot-static probes that are used to determine the local static and dynamic
pressures, respectively. These probes are Fairly rugged and can be easily put to use if there is
enough flow velocity to generate measurable pressure differentials. A complete flow
characterization in an experiment entails determining the velocity vector:, the velocity magnitude
and the flow pitch (c¢)and yaw (13)angles. A 3-hole probe can determine one of the flow angles,
(usually 13)and one of the flow components. The 5-hole probes on the other hand can determine
the complete velocity vector. The afore-mentioned probes require calibrations that are usually
provided by the manufacturer and some software to implement the calculations and derive the
required results. The calibrations are valid over a certain range of pitch and yaw angles (typically
_-30°). The validity restrictions are clue to flow separation on the probe surface at larger angles.
Typical error estimates are = 3° for flow angularity and 5% for velocity magnitude.
https://ntrs.nasa.gov/search.jsp?R=19960047141 2020-06-16T03:25:56+00:00Z
In the calibration of multi-hole probes, frequently dimensionless pressure ratios
are used as opposed to the pressures themselves. The pressure ratios have been found to yield
a more general calibration form that can be extrapolated to conditions other than the calibration
conditions, without significant loss in accuracy of the results. To put it differently, this form of
calibration affords its use at different flow Reynolds numbers. For example, it is fairly common
practice to use air calibrated probes in water flows. F_g. 1 provides a summary of the available
results from literature and the operational Reynolds numbers of some of MSFC's facilities.
There has been a long felt need at MSFC in particular and the research community in
general, for a dedicated test to address the Reynolds number applicability range in sulosonic air
flows of the multi-hole probe calibrations. To this end, a specific test apparatus was designed
and constructed. A series of test runs with 3-hole and 5-hole probes were conducted as par of
this test. The experiment parameter envelope also proved ideal for carrying out hot wire
anemometer calibrations to address its high Re response characteristics. This paper reports on
the results from the investigation..
The final paper format will comprise of a detailed description of the setup and its
performance validation followed by a description of a typical, routine (low Re) calibration of
multi-hole and hot wire probes. This will be followed by results and comparisons from the high
Re studies.
Some preliminary results are included in the next section.
TEST FACILITY AND PRELIMINARY RESULTS
A schematic representation of the spool piece used in the test is shown in Fig. 2 along
with the flow envelope and test conditions. The spool piece was mounted in the inlet section of
the NASA MSFC's TurOine Test Equipment (TTE). The blow down facility is capable of delivering
precisely metered flow at any set temperature (aml_ient to 400°F) for a duration ranging from 30
s for very high flow rates to up to an hour at low flow rates. The test section (straight section of
the spool piece) is 11 '° long with a diameter of 3". It is provided with 4 centrally (axial direction)
located ports to house differeent calibration probes. Flow surveys in the spool piece were initially
undertaken to measure the flow angularity (<1°), the extent of the central (uniform velocity) core
region and wall boundary layers. The turbulence level in the core region was also measured.
These tests were done in the facility validation stage to ensure the accuracy of the flow.
During the high Re testing phase, the test probe was oriented at precise angles to the
flow and the probe pressures and test parameters were documented. The tests were repeated for
different Mactl numbers (Ma) keeping Re the same. Several sets of data corresponding to
different Ma-Re combinations were recorded, For hot wire testing, temperature was an additional
parameter included ir_thetest _atrix. The L_.ach number range is from 0.2 co 0.6 and Re
range is from lO _ co lO° based on _he cesc section diameter.
The numbering convention and the pressure ratio definitions of a 5°hole prism probe are
shown in Fig. 3 and a typical lab calibration for the probe is shown in Fig. 4. Results (preliminary
at this stage) from the test are shown in Fig. 5. Data reduction at points 1, 2 and 3 noted on the
figure using the lab calibration (Fig. 4) is presented in tables 1 and 2. The initial results tend to
indicate that the conventional calibration method is fairly roDust and applicaDle at the high
Reynolds numbers tested.
A complete uncertainty estimation and results from the hot wire tests and complete data
analysis will be presented in the final version of the paper.
References
1. Huffman, G.D. et al., Flow direction probes from a Theoretical and Experimental Point of
View, Journal of Physics E, 13, 1980, pp. 751-760.
2. Treaster, A. L., and Yocum, A. M., The Calibration and Application of Five-Hole Probes, Penn.
State University Applied Research Lab Report TM 78-10, 1978.
3. Krause, L. N., and Dudzinski, T. J., Flow Direction Measurement with Fixed position Probes in
Subsonic Ftow over a range of Reynolds numbers, NASA TMX-52576, 1969.
Table 1: Preliminary data analysis at a few selected points (see Fig. S for Point Ids.)
Re d Point Id. Cp,pitch, Cp,yaw Calculated Calculated Actual Actual
Pitch Angle Yaw Angle Pitch Angle Yaw Angle
1.76x104 1 0.0711 -0.5403 2.529 ° -0.172' 0 0
1.47xl 05 2 0.0955 -0.7003 3.258 ° -7.815 = 0 0
1.5x105 3_ 0.4623 -2.612 8.170 ° -16.01 ° 0 -20
° There appears to be sensor overanging for this run. This may explain the error in the predicted
angles. This is under analysis.
Table 2: Velocity Analysis at a few selected points (see Fig. 5 for Point Ids.)
Re d Point ld. Calculated Actual Velocity % Error
Velocity
1.76xl 04 1 211.186 214.127 -1.370
1.47xl 05 2 217.510 216.107 0.065
1.5xl 05 3" 428.044 445.04 -3.819
* There appears to be sensor overanging for this run.
_Zu_an
KEau_e & Du_=in_kl
T--eas_eE & Toc_-
HGM WaueE Model
HGM ._i= Model
ASRMAZTE
Flow Vi_uali=auion
|..._0_e-.--I800 g'pm
...... -4_'q-"-46 m=/s
Calib=a=ion
!0 1
....... I ...... I ....... I ....... I ...... "I
!0 2 I0 3 10 4 1O 5 I0 6
, Reynold_ Num_e::
Fig. 1 Reynolds number ranges of experimental facilities and available results.
HGM: Hot Gas Manifold test
ASRMAFTE: Advanced Solid Rocket Motor Air Flow Test Equipment
Calibration refers to probe calibration in the MSFC calibration wind tunnel
References: Huffman [1]; Krause and Dudzinski [2] and Treaster and Yocum [3].
Oni O* !Oo
Lcon Ltest Ldiff
Fig. 2 Schematic of the Spool piece with the calibration test section.
5-Hole Probe Velocity Components (Yaw-Pitch Calibration)
Callbrmlon in the Ysw-Pltch mode:
v= = v'-_s# cos=
I ._
, ...11,) / _ i
M _1 ...._,.. I ,.i
P'F-. -:>-
T I I"""
=, D." "-...
°. I I
ReferenCe _' Pitch I
Plane I
\ I
Ptane "- ...
Upper, 1 (4)
0
LR",2 O) O
O_ Right, 4 (3)
Helldon, $ (S)
Lawtr,:) (2)
Probe Nomenclature
Cp, pitch = (P_ -P)) (,)
(P5-P )
cp,_w = (P' -P_) (2)
(P, -P )
Cp, total = (P_ - P'_) (31(P,- P)
cp,mdc = (p- P__) (4)
(P,-P)
Fig. 3
= (P) ÷P; +P, +P,) (s)4
Numbering Convection for 5-hole prism probes and the definition of pressure ratios.
5
4
3
ut_
2
>- 0
-2
-3
-4
-5
-5
100
75
5O
25
0
-30
Cp Pitch vs. Cp Yaw Cp Total vs. Pitch angle
' • , 1 • "" ' " .2
• . . • .
_!ll it"
.... 1.0 '
-4 -3 -2 -t 0 1 2 3 4 5 -30 -10 10 30
Cp Pitch Pitch angle
Cp Static vs. Pitch Angle
. ,,-_.
%.4 / ,_" -°_,_\ .-
• / .,, ,/:
ot _ / S
.22x,.-'_/,/ \_-_" /
't_ --'_".
_O
-10 10 30
Pilch angle
5-HOLE PROBE CALIBRATION
Serial Number C:B2556-3
Make
Calibration Condilions
Tunnel Velocity 184.426
Temperature 74
Number of Poinls 7 x 7
Date 03-11-1993
ED 35
NASA/MSFC Signalure
Fig. 4 Typical Calibration curves for a 5-hole Prism probe.
50
Prism Probe #1
25
0
- 5010,
-2
=-.4
o -.6
-.8
"1-010,
--o M- 0.2 I
,--- t_.,, 0.6
o-.- - 0.4
.- 4._b._al 3. .......... 2. ...... ---_
0 . _aD CaL
",. j
',,'-o M - 02. I
---' M- 0.6
,,,-4 - 0.4
10s
106
106
0
-.15
=,.
0
-.30
-.45
104
1.0
.8
o=.4
2
010,
+
1(_6 ' ,
Re=
CaL
106
106 -10+
Re d
NOTE: These resulcs are for probe sec_ings : 0 de E Yaw and 0 des. pi_ch.
9oin_1 and 2 are as shown in _he figure. Point 3 is for _i_ch = 0 & yaw = -20 de_
and hence is noc shown in this figure.
Fig. 5 Preliminary results from high Re testing of a S-hole prism probe.
7


High Reynolds Number Effects on Multi-Hole Probes and Hot Wire Anemometers

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