cfd use in venturi meter
DESCRIPTION
Computational fluid dynamicsTRANSCRIPT
APPLICATIONS OF COMPUTATIONAL FLUID DYNAMICS IN HYDRAULICS
• ADITYA KARAN• ABHIJEET SAVANT• NINAD PRABHUNE
• Guided By :• Dr. G.A. Hinge
WORK DONE TILL FIRST SEMESTER
• SELECTION OF THE SOFTWARE TO BE USED FOR THE VARIOUS FLUID DYNAMICS PROBLEMS.(ANSYS FLUENT)
• ACCESING THE RESULTS ACQUIRED FROM VARIOUS COMPUTATIONAL SOFTWARE
• PRACTICAL PERFORMANCE OF CALIBRATION OF VENTURIMETER
• SIMULATION OF THE SAME EXPERIMENT IN FLUENT• VALIDATION OF THE RESULTS SO AQUIRED WITH THE
PRACTICAL RESULTS.• THUS REACHING TO THE CONCLUSION THAT FLUENT CAN BE
USED TO CARRY FUTHER STUDY OF INSTRUMENTS
CALIBRATION OF VENTURIMETER
DETAILS OF VENTURIMETER( F M Lab, SCOE)
• Inlet Diameter= 25mm• Throat diameter= 16mm• Inlet diameter= outlet diameter• Length of inlet pipe=500mm• Length of convergent section=35mm• Length of divergent section=65mm
ABOUT VENTURI METER
• The Venturi meter was invented by the Italian Giovanni Venturi in 1797.
• To measure the volumetric flow rate of fluids.• GEOMETRY-Venturi meter there is first a converging
section.• Then there is a short section at the reduced diameter,
known as the throat of the meter.• Then there is a diverging section in which the cross
sectional area for flow is gradually increased to the original diameter.
Formulae For Calculating Discharge
• C = a1a2√(2g) / √(a1²-a2²)
• a1 = Area at inlet pipe.
• a2 = Area at throat section.• C= Coefficient of venturi meter.• Qth = C√H
• Qth = Theoretical Discharge.• H= Difference in venturi head.
• Qact = C.Cd√H
• Qact=Cd Qth
• Cd= Coefficient of discharge. * Cd is introduced in the equation because to
take loss of energy into account.
Comparison between lab and fluent results:Validation Of CFD
H Lab (cm) H Fluent (cm) Klab K Fluent
30 29.1 0.93 0.923
22.1 20.90 0.92 0.9243
9.6 13.63 0.93 0.9250
5.0 5.8 0.92 0.9420
4.0 3.59 0.89 0.8980
1.80 1.96 0.90 0.8790
AFTER VALIDATION OF THE RESULTS…
• Varied the ratio of (throat diameter : inlet diameter )• Changed the inlet diameter and kept the inlet
diameter constant• Found the appropriate ratio of throat diameter : inlet
diameter.• Then Changed the throat diameter according to the
ratio found earlier hence optimizing the design of Venturi meter
VARIATION OF RATIOS OF THE DIAMETER OF THE THROAT AND THE INLET SECTION
PARAMETER
CASE 10.4
CASE 20.5
CASE 3 0.6
ORI. CASE
CASE 40.7
CASE 50.8
CASE 60.9
RATIO OF DIAMETER
0.4:1 0.5:1 0.6:1 0.64:1 0.7:1 0.8:1 0.9:1
INLETDIAMETER(m)
0.04 0.032 0.027 0.025 0.023 0.02 0.018
THROATDIAMETER(m)
0.016 0.016 0.016 0.016 0.016 0.016 0.016
INLET AREA ×10-4
(m2)
1.257 8.05 5.31 4.90 3.8 3.14 2.43
THROAT AREA×10-4
(m2)
2.01 2.01 2.01 2.01 2.01 2.01 2.01
RESULTS FOR DIFFERENT CASESUSING CFD.
CASE 10.4
CASE 20.5
CASE 30.6
CASE 40.7
CASE 50.8
CASE 60.9
DISCHARGE (m3/s)
4.95×10-04
CONSTANT OF
VENTURIMETER×10-04
9.02 9.2 9.63 10.5 11.59 15.82
Qth×10-04
-- 5.26 4.96 5.47 5.21 6.43
Qact -- 0.4856 0.4575 0.4835 0.4777 0.4836
COEFFICIENT OF VENTURMETER
-- 0.922 0.9234 0.88 0.916 0.75
CASE 2CASE 1 CASE 2 CASE 3 CASE 4 CASE 5 CASE 6
DISCHARGE (m3/s)
4.59×10-04
CONSTANT OF
VENTURIMETER×10-04
9.02 9.2 9.63 10.5 11.59 15.82
Qth×10-04
-- 8.65 4.82 0.549 4.89 5.48
Qact -- 0.4896 0.4441 0.4851 0.4426 0.4366
COEFFICIENT OF VENTURMETER
-- 0.9133 0.9210 0.88 0.9048 0.7965
CASE 3:CASE 1 CASE 2 CASE 3 CASE 4 CASE 5 CASE 6
DISCHARGE (m3/s)
4.25×10-04
CONSTANT OF VENTURIMETER
×10-04
9.02 9.2 9.63 10.5 11.59 15.82
Qth×10-04
-- 4.69 4.66 5.14 4.73 6.49
Qact -- 0.4169 0.4131 0.4450 0.4092 0.4050
COEFFICIENT OF VENTURMETER
-- 0.8887 0.8873 0.8659 0.8648 0.6248
GRAPH SHOWING RESULTS
1 2 3 4 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Results
Case 1 Case 2 Case 3
Towards optimizationAnalyzing around case 3
PARAMETER CASE 10.525
CASE 20.55
CASE 3 0.575
CASE 40.62
CASE 50.64
RATIO OF DIAMETER
0.525:1 0.55:1 0.575:1 0.62:1 0.624:1
INLETDIAMETER(m)
0.0304 0.029 0.0278 0.0258 0.025
THROATDIAMETER(m)
0.016 0.016 0.016 0.016 0.016
INLET AREA ×10-4 (m2)
7.3 6.6 6.1 5.2 4.9
THROAT AREA×10-4 (m2)
2.01 2.01 2.01 2.01 2.01
RESULTSCASE 1
0.4CASE 2
0.5 CASE 3
0.6 CASE 4
0.7CASE 5
0.8DISCHARGE
(m3/s) 4.95×10-04
CONSTANT OF
VENTURIMETER×10-04
9.3 9.4 9.4 9.7 9.8
Qth×10-04
5.5 5.2 5.3 5.2 5.4
Qact 0.4831 0.4812 0.46138 0.4885 0.4813
COEFFICIENT OF VENTURMETER
0.8809 0.9257 0.8679 0.9336 0.8924
RESULTS
1 2 3 4 5 6 70.82
0.84
0.86
0.88
0.9
0.92
0.94
OPTIMIZED RESULTS
OPTIMIZED RESULTS
From these results we found the value of the ratio is 0.62
VARIATION OF DIAMETER OF THROAT ACCORDING TO OUR OPTIMISED RATIO OF
0.62
PARAMETERS CASE 1 CASE 2 CASE 3
Peizometeric Head 0.387 0.407 0.333
inlet radius 0.0125 0.02 0.025
throat radius 0.008 0.0124 0.0155
inlet area 0.00049107 0.001257143 0.001964286
throat area 0.00020114 0.000483246 0.000755071
Constant of venturi 0.00097654 0.002318428 0.003622544
q th 0.0006075 0.001479077 0.002090431
q act 0.47793 1.2422 1.947391
coefficient of discharge 0.78671899 0.839848072 0.931574142
RESULTS USING CFDPARAMETER CASE 1 CASE 2 CASE 3 CASE 4
DISCHARGE (m3/s)
4.90×10-04 4.90×10-04 4.90×10-04 4.90×10-04
CONSTANT OF VENTURIMETER
9.75×10-04 9.75×10-04 9.75×10-04 9.75×10-04
PRESSURE HEAD(cm)
29.8 27.9 29.1 27.9
QTH 5.325×10-04 5.15×10-04 5.35×10-04 5.15×10-04
CD 0.919 0.949 0.93 0.95
GRAPH SHOWING THE RESULTS
1 2 30.7
0.75
0.8
0.85
0.9
0.95
CONCLUSIONS:
• The Avg. Cd found was 0.923 but the value of the Cd is usually taken as 0.98.
• We found by changing the ratio of inlet to throat diameter the efficient value of the ratio is 1.6 that we got from FLUENT.
• We found by changing the length of convergent section that efficient value is 0.016m and we are still working on that parameter.
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