ESD1 Pipe Flow part 2 LMS PDF

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Pipe flow part 2...

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Engineering Systems Design 1 Lecture 06 – Pipe Flow 2 pollev.com/esdpoll

Learning Objectives • To implement an if-else statement in MATLAB for pressure drop • To model fluid flow with FITTINGS • Apply to fluid networks without pumps Engineering Bernoulli Equation

Lecture 06 – Pipe Flow 2

2

Engineering Systems Design 1

P1

P2

Pressure Drop in Pipe Flow

L

• Change in pressure in the pipe drop according to FORM 1: Units of length (m): FORM 2: Units of pressure (Pa): 1 %&' ( ∆" = $+ + 2*

$%&' ( ∆" = 2*

Calculation would have to choose f: If Re < 2000

64 %= /0 Lecture 06 – Pipe Flow 2

Else if Re > 2000 %= −1.845+67 3

(

1 6.9 ;⁄ < + 3.7 /0

6.66

Engineering Systems Design 1

What if I had a script that worked for Laminar and Turbulent Inputs

It would use the same inputs and outputs, but what do I have to change in the calculation section?

Outputs

Calculation would have to choose f, based on Re

64 != %& Lecture 06 – Pipe Flow 2

OR

7

1

!= −1.8+,-./

6.9 %& + 4

3⁄ 4 3.7

....

Engineering Systems Design 1

•

IF Then Else statements IF-Then or IF-Else statements are decision making structures in

MATLAB • Help if if Conditionally execute statements. The general form of the if statement is if expression statements ELSEIF expression statements ELSE statements END

•

Form we’ll use: if expression statements ELSE statements END

Lecture 5 06 – Pipe Flow 2

Engineering Systems Design 1

• • •

IF Then Else statements Example:

Calculate a function circle Where circle = - sqrt(1- x^2) if x < 1 And circle = sqrt(1+x^2) if x > 1 Test the if statement for x = 0.5, 1.1, 2 Test x = 1

Lecture 6 06 – Pipe Flow 2

Engineering Systems Design 1

Add IF statement to Pressure Drop Script from last lecture • In calculation section, use an if else statement to select the proper expression for f, depending on Re number

Lecture 7 06 – Pipe Flow 2

Engineering Systems Design 1

Test Cases, Check the Re and f Case 1

Case 2

Case 3 Case 4

Case 5 2000 L/hr

Q

1.8 m3/hr

0.5 m3/hr

5 L/min

5 L/min

diameter (mm)

150 mm

150 mm

150 mm

30 mm 30 mm

30 mm

Density (kg./m3)

998

998

998

998

784

Visc. (Pa s)

0.00089

0.00089

0.00089

0.0008 0.0008 9 9

0.005

Re

4,759

1322

793

3966

3697

f

0.385

0.0484

0.0807

Lecture 06 – Pipe Flow 2

8

2000 L/hr

998

26,440

Engineering Systems Design 1

The Systems Design in Sub-Systems!!!!

WATER TOWER

Distribution Sub-System

Pump Sub-System

Water Storage Tank

Tap

Particle Filter

Tap

IIM Membrane Unit

100 m

Pump

There are valves, pipe entrances, exits, bend, taps, fitting, unions. Do these effect the pressure drop?

Lecture 06 – Pipe Flow 2

9

Engineering Systems Design 1

Pressure Drop with Fittings ∆" #$

1 = $

'

()*+,- ./ 010,2

345 6 28

+

'

1

2 /1::1(;2

56<

K values

• Fittings have can have bumps, bends, sharp edges. All lead to energy dissipation through friction. • More complex than pipes to capture, so different geometries are empirically determined and tabulated. • Simple fittings are single numbers – Elbow, Union, tee, entrance, exit

• More complicate geometries, more involved – Valves, contractions, expansions, membranes

Lecture 06 – Pipe Flow 2

10

Engineering Systems Design 1

Fittings Fitting 45 ° elbow 90 ° elbow 180 ° bend Tee – run through – branch blocked Tee – all other flow patterns Coupling Union

K 0.35 0.75 1.5 0.4 1 0.04 0.04

Pipe exit Pipe entrance

1 0.75

Gate valve – open Gate valve – ¾ open Gate valve – ½ open Gate valve – ¼ open

0.17 0.9 4.5 24

Lecture 06 – Pipe Flow 2

11

Engineering Systems Design 1

Fittings Fitting 45 ° elbow 90 ° elbow 180 ° bend Tee – run through – branch blocked Tee – all other flow patterns Coupling Union

K 0.35 0.75 1.5 0.4 1 0.04 0.04

Pipe exit Pipe entrance

1 0.75

90o Elbow

Tee

Union 180o Bend

Lecture 06 – Pipe Flow 2

12

Engineering Systems Design 1

Fittings Fitting

K Gate Valve

Gate valve – open Gate valve – ¾ open Gate valve – ½ open Gate valve – ¼ open

0.17 0.9 4.5 24

Globe valve – open Globe valve – ½ open Gate valve – open Gate valve – ¾ open Gate valve – ½ open Gate valve – ¼ open

6.0 9.5 0.17 0.9 4.5 24

Lecture 06 – Pipe Flow 2

13

Engineering Systems Design 1

Fittings • More complicate geometries, more involved – Valves, contractions, expansions, membranes, Reducers Re1 < 2500 ! = 1.2 +

Re1 ≥ 2500 160 Re)

*) *+

,

−1

! = 0.6 + 0.480)

*) + *) *+ *+

+

D1

D2

−1

Expanders Re 1 < 4000 ! =2 1−

Lecture 06 – Pipe Flow 2

Re1 ≥ 4000 *) *+

,

! = 1 + 0.80)

14

*) 1− *+

+ +

D1

D2

Engineering Systems Design 1

Pressure Drop across an elbow P1

P2 Q = 1.8m3 /hr Pipe and Fluid: D = 150 mm Density = 1000 kg/m3 Visc. = 0.00089 Pa s e = 45.0 X10-6 m

Q = 1.8 m3/hr Q= 1.8/3600 m3/s = 5.0X10-4 m3/s v= Q/(pd2/4) =0.0283 m/s

Lecture 06 – Pipe Flow 2

∆" 1 '() * + = $ 2, #$

.

/0110234

1 * ) 5 2

∆" 1 1 * ) 5 = #$ $ 2

15

Engineering Systems Design 1

Pressure Drop across an elbow P1

P2 Q = 1.8m3 /hr Pipe and Fluid: D = 150 mm Density = 1000 kg/m3 Visc. = 0.00089 Pa s e = 45.0 X10-6 m

∆" 1 '() * + = $ 2, #$

Q = 1.8 m3/hr Q= 1.8/3600 m3/s = 5.0X10-4 m3/s v= Q/(pd2/4) =0.0283 m/s

.

/0110234

1 * ) 5 2

∆" 1 1 * ) 5 = #$ $ 2

K = 0.75 ∆" = # Lecture 06 – Pipe Flow 2

6

*

) * 5 = 998

6

*

0.0283*...