EXPERIMENTAL PROCEDUREDocument: Hydraulics Lab Expt_Orifice Meter.docAuthor: Muhammed BhuiyanSave...

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EXPERIMENTAL PROCEDUREDocument: Hydraulics Lab Expt_Orifice Meter.docAuthor: Muhammed BhuiyanSave Date: 09/03/20188Page 6 of 10Data Sheet Date: _______________ Student Name & ID: ____________________________________________ 1. Orifice diameter, d (m) = 0.003 mSl Head, h (m) Horizontal distance, x(m)Vertical distance, y (m) yh (m)Cv (obtain from slope of graph)high low high low high low high low XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX2. Orifice diameter, d (m) = 0.006 mSl Head, h (m) Horizontal distance, x(m)Vertical distance, y (m) yh (m)Cv (obtain from slope of graph)high low high low high low high low XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXXSignature of the Lab Demonstrator:  XXXXXXXXXX0 0 XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX0 0 XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXX XXXXXXXXXXDocument: Hydraulics Lab Expt_Orifice Meter.docAuthor: Muhammed BhuiyanSave Date: 09/03/20188Page 9 of 10Data Sheet Date: ________________ Student Name & ID: ____________________________________________ 1. Orifice diameter, d (m) = 0.003 m Area of the orifice, Ao (m2) =Sl Head, h(m)Volume,V (m3)Time, t(sec)Flow rate, Q (m3/sec)h (m0.5) Cd (obtain from slope)123452. Orifice diameter, d (m) = 0.006 m Area of the orifice, Ao (m2) =Sl Head, h(m)Volume, V (m3)Time, t(sec)Flow rate, Q (m3/sec)h (m0.5) Cd (obtain from slope)12345Signature of the Lab Demonstrator: 0.3420.3280.310.286N/A - - - -0.0010.0010.0010.00159.1356.8558.3662.910.3440.3260.310.2830.0010.0010.0010.001-N/A - - -16.516.2215.1716.81 EXPERIMENTAL PROCEDURE        Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 1 of 10            HYDRAULIC LAB EXPERIMENT ON ORIFICE METER                                          Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 2 of 10  EXPERIMENTAL PROCEDURE  Objective To determine the coefficient of velocity and coefficient of discharge of two different sizes orifices.Scope By measurement of the jet issuing from an orifice in the side of a reservoir under steady flow conditions (constant reservoir head).Equipment In order to complete the demonstration we need a number of pieces of equipment.  The Hydraulics Bench which allows us to measure flow by timed volume collection.  The Orifice and Jet Apparatus.  A Stopwatch to allow us to determine the flow rate of water.  Technical Data The following dimensions from the equipment are used in the appropriate calculations. If equired these values may be checked as part of the experimental procedure and replaced with your own measurements.   Diameter of small orifice             = XXXXXXXXXXm Diameter of large orifice             = XXXXXXXXXXm Surface area of reservoir, AR   =  1.832 × 10-2  m2Procedure   Equipment Set Up Position the reservoir across the channel on the top of the hydraulic bench and level the eservoir by the adjustable feet using a spirit level on the base. Remove the orifice plate by eleasing the two knurled nuts and check the orifice diameter; take care not to lose the O-ing seal. Replace the orifice and connect the reservoir inflow tube to the bench flow connector. Position the overflow connecting tube so that it will discharge into the volumetric tank; make sure that this tube will not interfere with the trajectory of the jet flowing from the orifice.  Turn on the pump and open the bench valve gradually. As the water level rises in the eservoir towards the top of the overflow tube, adjust the bench valve to give a water level of 2 to 3 mm above the overflow level. This will ensure a constant head and produce a steady flow through the orifice.   Taking a Set of Results The methods for obtaining results in the two exercises are described separately.        Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 3 of 10 EXERCISE 1: Determination of Coefficient of Velocity from Jet Trajectory    Theory From the application of Bernoulli's Equation (conservation of mechanical energy for a steady, incompressible, frictionless flow), the ideal orifice outflow velocity at the jet of the vena contracta (naowest diameter) is  ghVi 2where, h is the height of fluid above the orifice.The actual velocity is  ghCV v 2                                XXXXXXXXXX1)vC  is the coefficient of velocity, which allows for the effects of viscosity and, therefore 1vC . vC  can be determined from the trajectory of the jet using the following argument: Neglecting the effect of air resistance, the horizontal component of the jet velocity can be assumed to remain constant so that in time, t  the horizontal distance travelled,  Vtx                                         XXXXXXXXXX2)Because of the action of gravity, the fluid also acquires a downward vertical (y-direction) component of velocity. Hence, after the same time, t, (i.e. after travelling a distance x) the jet will have a y displacement given by  22tgy   which can be reaanged to give:         Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 4 of 10   gyt2                                            XXXXXXXXXX3) Substitution for t from Eq (3) into Eq (2) and for V  from Eq (1) into Eq (2) yields:  yhxCv2  Hence, for steady flow conditions, i.e, constant h, vC  can be determined from the x and y coordinates of the jet. A graph of  x plotted against  yh  will have a slope of vC2 . So, Cv = slope/2 will be the answer.Procedure Position the overflow tube to give a high head. Note the value of the head. The jet trajectory is obtained by using the needles mounted on the vertical backboard to follow the profile of the jet. Release the securing screw for each needle in turn and move the needle until its point is just immediately above the jet and re-tighten the screw. Attach a sheet of paper to the back-board between the needle and board and secure it in place with the clamp provided so that its upper edge is horizontal. Mark the location of the top of each needle on the paper. Note the horizontal distance from the plane of the orifice (taken as x = 0) to the co-ordinate point marking the position of the first needle. This first co-ordinate point should be close enough to the orifice to treat it as having the value y = 0. Thus y displacements are measured relative to this position. Estimate the likely experimental eors in each of the quantities measured.Repeat this test for a low reservoir head.Then repeat the above procedure for the second orifice.Plot  yh  vs  x and determine the slope of the graph. The velocity coefficient vC  is equal to the average of slope/2.Hint: Plot the above yh  in the x-axis and x in the y-axis.        Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 5 of 10 Sample plots    So, Cv = 1.8481 ÷  2 = 0.924  So, Cv = 1.794 ÷  2 = 0.897         Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 6 of 10 Data Sheet XXXXXXXXXXDate: _______________  Student Name & ID: ____________________________________________ 1. Orifice diameter, d (m) = 0.003 m Sl Head, h (m) Horizontal distance, x

Ankita · Accepted Answer

EXPERIMENTAL PROCEDURE
HYDRAULIC LAB EXPERIMENT ON
ORIFICE METER
 (
Document: Hydraulics Lab 
Expt_Orifice
 
Meter.doc
Author:
 
Muhammed
 
Bhuiyan
 
Save Date:
 
09/03/20188
Page 
11
 of
 
10
)
EXPERIMENTAL PROCEDURE
Objective
To determine the coefficient of velocity and coefficient of discharge of two different sizes orifices.
Scope
By measurement of the jet issuing from an orifice in the side of a reservoir under steady flow conditions (constant reservoir head).
Equipment
In order to complete the demonstration we need a number of pieces of equipment.
· The Hydraulics Bench which allows us to measure flow by timed volume collection.
· The Orifice and Jet Apparatus.
· A Stopwatch to allow us to determine the flow rate of water.
Technical Data
The following dimensions from the equipment are used in the appropriate calculations. If required these values may be checked as part of the experimental procedure and replaced with your own measurements.
Diameter of small orifice	= 0.003 m Diameter of large orifice	= 0.006 m  Surface area of reservoir, AR	= 1.832 × 10-2 m2
Procedure
Equipment Set Up
Position the reservoir across the channel on the top of the hydraulic bench and level the reservoir by the adjustable feet using a spirit level on the base. Remove the orifice plate by releasing the two knurled nuts and check the orifice diameter; take care not to lose the O- ring seal. Replace the orifice and connect the reservoir inflow tube to the bench flow connector. Position the overflow connecting tube so that it will discharge into the volumetric tank; make sure that this tube will not interfere with the trajectory of the jet flowing from the orifice.
Turn on the pump and open the bench valve gradually. As the water level rises in the reservoir towards the top of the overflow tube, adjust the bench valve to give a water level of 2 to 3 mm above the overflow level. This will ensure a constant head and produce a steady flow through the orifice.
Taking a Set of Results
The methods for obtaining results in the two exercises are described separately.
EXERCISE 1: Determination of Coefficient of Velocity from Jet Trajectory
Theory
From the application of Bernoulli's Equation (conservation of mechanical energy for a steady, incompressible, frictionless flow), the ideal orifice outflow velocity at the jet of the vena contracta (narrowest diameter) is
 (
2
gh
)Vi 
where, h is the height of fluid above the orifice.
The actual velocity is
 (
2
gh
)V   Cv
(1)
Cv is the coefficient of velocity, which allows for the effects of viscosity and, therefore
Cv  1. Cv can be determined from the trajectory of the jet using the following argument:
Neglecting the effect of air resistance, the horizontal component of the jet velocity can be assumed to remain constant so that in time, t the horizontal distance travelled,
x  Vt	(2)
Because of the action of gravity, the fluid also acquires a downward vertical (y-direction) component of velocity. Hence, after the same time, t, (i.e.

EXPERIMENTAL PROCEDURE Document: Hydraulics Lab Expt_Orifice Meter.doc Author: Muhammed Bhuiyan Save Date: 09/03/20188 Page 6 of 10 Data Sheet Date: _______________ Student Name & ID:...

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