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.

THANK YOU