PASCO ME-8598 User Manual
®
Venturi Apparatus
ME-8598
Instruction Manual
012-09486B
*012-09486*
®
Venturi Apparatus
Table of Contents
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Experiment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Pre-Setup Measurements 4
Setup 5
Procedure 5
Analysis 5
Further Analysis 6
Clean-up 6
Storage 6
Appendix A: Quad Pressure Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
DataStudio 7
Xplorer GLX (Standalone Mode) 7
Appendix B: Fluid Supply and Flow Rate Measurement Options . . . . . . . . . . . . . . . . . . 8
Air 8
Water 10
Appendix C: Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Material Safety Data Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2
Venturi Apparatus
®
1
2
34 5
6
ME-8598
Included Equipment Part Number Air Method: Recommended Equipment 1Part Number
1. Venturi Apparatus base and top plate ME-8598 Spirometer Sensor
2. T-knob Screws (qty. 8) 617-024 One of the following:
3. Spirometer Tubing, 2.5 cm ID, 15 cm long 640-053 Shop Vacuum (or similar air supply)
4. Rubber Stoppers, 1-hole (qty. 2) 648-09597 Balloon and balloon pump
5. Restriction Clamps (qty. 2) 640-052 Water Method: Recommended Equipment
6. Fluid Tubing, 6 mm ID, 6 m long 640-012 Water Reservoir (or similar container) ME-8594
Required Equipment Container to catch water
Quad Pressure Sensor PS-2164 Table Clamp ME-9472
PASPORT Interface
5
See PASCO
catalog or
www.pasco.com
1
See page 8 for more information.
2
The use of this sensor and the Quad Pressure Sensor simultaneously requires a multi-port PASPORT Interface (such as Xplorer
GLX or PowerLink) or two single-port interfaces.
3
See pages 8–10 for more information.
4
See pages 10–13 for more information.
5
PASPORT interfaces include Xplorer GLX (PS-2002), PowerLink (PS-2001), AirLink (PS-2005), Xplorer (PS-2000), and USB Link
(PS-2100)
2
PS-2152
3
4
120 cm rod ME-8741
2 Three-finger clamps SE-9445
One of the following:
Motion Sensor
Rotary Motion Sensor
Force Sensor
2
2
2
PS-2103
PS-2120
PS-2104
Stopwatch SE-8702B
3
®
Venturi Apparatus 012-09486B Introduction
P
A
u
P
0
A
0
u
0
Figure 1: Fluid flow through a pipe of varying
diameter
PP
0
1
2
-- -
ρυ
2
υ
0
2
–()–=
Introduction
In the Venturi Apparatus, air or water flows through a channel of varying width. As
the cross-sectional area changes, volumetric flow rate remains constant, but the velocity and pressure of the fluid vary. With a Quad Pressure Sensor connected to the
built-in Pitot tubes, the Venturi Apparatus allows the quantitative study and verification of the Continuity Equation, Bernoulli’s principle, and the Venturi effect.
The model ME-8598 Venturi Apparatus includes the connectors and tubing needed
for doing the experiment with either air or water. This manual contains complete
experiment instructions, i ncludi n g sev eral op tio ns for flu id su pply and fl ow-rate measurement.
Theory
An incompressible fluid of density ρ flows through a pipe of varying diameter (see Figure 1). As the cross-sectional area decreas es
from A
υ
(large) to A (small), the speed of the fluid increases from
0
to υ.
0
The flow rate, R, (volume/time) of the fluid through the tube is
related to the speed of the fluid (distance/time) and the cross-sectional area of the pipe. The flow rate must be constant over the
length of the pipe. This relationship is known as the Continuity
Equation, and can be expressed as
(eq. 1) R = A
0υ0
= Aυ
As the fluid travels from the wide part of the pipe to the constriction, the speed
increases from υ
to υ, and the pressure decreases from P0 to P. If the pressure
0
change is due only to the velocity change, Bernoulli's Equation can be simplified to:
(eq. 2)
Experiment
This experiment can be conducted with either air or water. Appendix B contains
equipment lists and instructions specific to each method.
Note: You can use a PASPORT interface (or interfaces) connected to a computer running
DataStudio software or on an Xplorer GLX interface in standalone mode (without a computer).
For instructions on collecting, graphing, and analyzing data, press F1 to open DataStudio on-line
help, or see the Xplorer GLX Users’ Guide.
Pre-Setup Measurements
Remove the top plate from the apparatus. Measure the depth of the channel and the
widths of the wide and narrow sections. Calculate the largest cross-sectional area (A
and the smallest cross-sectional area (A
4
)
).
S
L
®
Model No. ME-8598 Experiment
Figure 2: Quad Pressure Sensor connected to apparatus
Quad Pressure Sensor
To Quad Pressure
channels: 2 3 4
Fluid flow
1
Setup
1. Connect the Quad Pressure
Sensor to your PASPORT
interface (but do not connect
tubing to the pressure ports
yet). If you are using a computer, start DataStudio.
2. Calibrate the Quad Pressure
Sensor (see Appendix A).
3. Connect each of the four pres-
sure tubes extending from the
underside of the apparatus to
the ports of the Quad Pressure
Sensor as indicated in Figure
2.
Important: Do not allow water to enter
the sensor. Ensure that there is no
water near the sensor end of the pressure tubes.
4. Place the top plate on the
apparatus and secure it with
eight T-knob screws. Tighten
the screws no more than necessary to prevent leaking.
5. Set up the fluid supply and flow-rate measurement as described in Appendix B.
Procedure
1. Start fluid flow.
2. Start data collection on the computer or interface.
3. Continue data collection while observing the pressure measurements on a graph
display . Obtain a few seconds’ worth of goo d data before stopping dat a collection
and fluid fl ow.
Analysis
1. View your data on a graph of pressure versus time.
2. Select a time interval of about 2 seconds in which all off the pressure measure-
ments are relatively clean (though not necessarily constant or noise-free).
3. Within this time interval, determine the average of each pressure measurement:
P
, P2, P3 (and P4 if you will do the Further Analysis below).
1
4. Over the same 2-second interval, determine the average flow rate, R.
5. If there were no friction or turbulence in the channel, the pressures in both wide
sections (P
and P3) would be equal; however, you will find that this is not the
1
case. Because the channel is symmetrical about Point 2, you can estimate the
pressure lost at Point 2 due to friction and turbulence by assuming that it is half
of the pressure lost between Point 1 and Point 3. In other words, if the tube were
5
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