Presentation Hydraulic Bench

7/27/2019 Presentation Hydraulic Bench

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Hydraulic Bench:

Jet Impact, Flow through Orifice

Carla Feliciano(Leader)

Neshma Lopez (Data Management)

Christian Arroyo (Experimenter)

Derick Morales (Data Analysis)

INQU4034

Prof. Natacha Souto


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Agenda

Objectives Fundamental Theory

Safety Rules Equipment Description

Experimental Procedure Data Analysis

Work Plan

Lab Tour


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OBJECTIVES

Investigate the validity of theoretical equations thatdescribe the force exerted by a jet of water overtargets different geometries.

Determine the discharge coefficients and velocity

coefficients of an orifice.

Compare experimental values and slopes withtheoretical values.


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What are fluids?

Are substances that deform under an applied shear stress.Newtonian

Continues to flow

regardless of the forces

acting on it.

du

Non-Newtonian

Its viscosity is variable

based on applied stress.

= -dy

(Pa)

= velocity gradient (s-1)dudy

= shear stress (Pa)

= fluid viscosity (Pa s-1)

du

dy


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MACROSCOPIC MASS BALANCE Considering a continuous flow on steady state

Mass Balance

In steady state flow system with a single inlet and outlet.

Theres no accumulation so the term dmtot/dt = 0.

System

< v >1

1

m 2

m

222111 SvSvdt

dmtot

222111 SvSv

Where:

= SV

- mass flow (kg/s)

- density (kg/m3)

S - flow area (m2)

- average velocity (m/s)v

< v >2


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MOMENTUM BALANCEIN FLUID MECHANICS

Where:

= Change in momentum

dt = Change in time

= Velocity vector (m/s)

= External force

= Opposite external force

21

12

1212

VVmFF

FVVmdt

Md

VVdtmVdtmVdtmMd

e

e

V

Md

F

eF


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Flat Plate target

V2

V1

Hemispherical target

V2

V2 V2

V1

AgQ

m

A

Q

A

QQF

VmVVmF

V

p

y

yyyy

y

2

2

121

20

AgQ

m

A

QVmF

VVmVVmF

VV

p

yy

yyyyy

yy

2

22

2

2

1

1121

12

JET IMPACT


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BernoullisEquation

Assumptions between any two points

Flow along a streamline.Steady flow.Inviscid flow (negligible viscous effects).Incompressible flow.No heat transfer.

No mechanical work.

(1) and (2):

v1 (J)P (N/m2) z (m) g (m/s2) P1/! (J)

2 gz( (J)

Pressure Elevation Acceleration of gravity Flow work Kinetic energy Potential energy

2

2

22

1

2

11

22Z

g

V

g

PZ

g

V

g

P


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TORRICELLIS EQUATION

2

222

1

211

22Z

g

V

g

PZ

g

V

g

P

g

VZZ

2

22

21

g

Vh

2

2

ghV 2

Point of reference is where the pressure is minimum (Patm)

Torricellis equation

Notes:

Area of tank is much greater than area of orifice

No friction losses in the system The area of the orifice = area vena contracta

Assuming that:

1) Steady State

2) Negligible friction effect

3)

4) h= Z1 - Z2

5) V1= 0 and V2= V

6) = constant


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ACTUAL ORIFICE DISCHARGE

CD = Discharge

factor = 0.637

A0

Fig. 15.5-5 BSL p. 471

AVC

ghCAQ

CCC

ghCACVAQ

Do

VCD

VoCvcvc

2

2

Fluid exits the orifice taking a y direction in a time t:y= (1/2) gt2

In that time t it runs a horizontal distance in t:

x= Vt


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ORIFICES VELOCITY COEFFICIENT Combining equations

to obtain:

y

gxV

2

ghy

gx

V

VC

i

v2

1

2ghVi 2

yCh

x

v

22

4

24 VC


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FLOW THROUGHAN ORIFICE

(UNSTEADY STATE MODALITY) No water enters the container and volume changes through

time t.

Where:AR= Tank cross-sectional area (m

2)

hhgAC

At

ghAC

dhA

Q

dhAt

dt

dhAdt

hAdQ

oD

R

h

h

oD

R

h

hR

R

R

1

2

2

211

h1

h

t (s)

1 (1

2)

=2

02


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General Safety Aspects


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Specific Safety Aspects


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15

Sump tank 200 L Measurement tank 48 L

Supply hose

A pump 0 to 60 L/min & 200 W motor

Hydraulic Bench Equipment Description

Reserve Tank

R

200L

G

L

Pump

NA

48LNB

6L

Hydraulic Bench Schematic Diagram

Discharge

Avoid

tank to

overflow

Presure Clock

tube


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GeneralSetup

Place desiredapparatus on

hydraulic benchand level

Check waterreserve level

At the end,shutdown and

disconnectequipment

Connect testequipment to the

water source


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JetImpact

Weights

Top View and Side-Lid View

Jet Impact Apparatus

Targets


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FlowThroughOrifice

Orifice

Water level

Orifice

Hook and Needle


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Accessories

Pyrometer withImmersion Thermocouple

Acetone

Orifice Fittings Weir, grate and plug

Bucket, graduated

cylinder, and chronometerBubble Level Measuring Tape


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JET IMPACT

1. Connect Pipe lines.

2. Remove upper lid and

install target. Make sure the

device is leveled.

3. Adjust weight plate and

open water valve, until

Equilibrium is reached

4. Place a 20 g weight and wait

until equilibrium is reached.

5. Open the valve and

requilibrate

6. Repeat the previous step

with 10g weight increments.


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Verify thewater level

Prepare andlevel out

theequipment

Do all thenecessary

connections

Make surethe tank is

closed

Adjust theindicator s

height withthe orifices

center

21

Write downheight and

distance

Moveindicator

horizontally

Determinea

volumetricflow

Wait for

water level

to be

stationary

Place indicatorhorizontally 10

cm from theorifice

Establish awater flow

Check waterlevel every

20 sec

Record timefor h1 and h2

Closevalve and

turn off the

pump

Unsteady state

x, y


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REVIEWOF OBJECTIVES

Validate equations that describe the forces exertedby a jet of water

upon targets of different configurations.

Determine the discharge coeff icient(CD) and the orifices velocity

coefficient(CV).

Compareresultswith literature values.


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Data Analysis:JetImpact

Plane Target Hemispherical Target

R2

= 1

m1,theo

-m1,exp%Error= x 100

m1,exp

23 /22 smi

QQ

2 = 21

1 Ag

Ag

2

=

(2 2) = 2 (2 2)

mp

(kg)


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DATA ANALYSIS - FLOW THROUGHAN ORIFICE

(STEADY STATE) Measure volume, time, and h

Calculate volumetric flow

Solve for CD and compare with theoretical results

CD =0.637

gCA Do 2)(2

3

h(m)

Q(m

3/s)2

)2()(

2

0

2

ghCAQ D

24

25


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ORIFICES VELOCITY COEFFICIENT

Measure the x, y, and hto obtain Cv

Solve for CV and compare with theoretical results

CV = 0.98

24 4 VC

)(2

mh

x

y(m)

yC

h

xV2

2

4

25

26


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(UNSTEADY STATE) Discharge coefficient

Measure h1 , h and t

Solve for discharge coefficient CDCD = 0.637

hhgACA

toD

R

12

2

gAC

A

oD

R

2

25

t (s)

2/11 mhh

26


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SCHEDULE

Day 1

Jet Impact

Day 2

Orifice Flow (Steady and unsteady-state).

Verify first run data and calculations.

Day 3

Additional experimentation (if necessary).


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References

Bird, Stewart, Lightfoot. Transport Phenomena. New York, John Wiley and Sons. 2002.

Munson, Young, Okiishi, Fundamentals of Fluid Mechanics. John Wiley. 2006.

Green, Perry. Perrys Chemical Engineers Handbook,

2008. 8th Ed. McGraw-Hill, New York

Experimento: Banco Hidrulico. Laboratorio de Operaciones Unitarias; Departamento

de Ingeniera Qumica (RUM); Mayagez, PR.

(2013). Spirax Sarco. In Types of Steam Flowmeter. Retrieved August 26, 2013, from

http://www.spiraxsarco.com/resources/steam-engineering-

tutorials/flowmetering/types-of-steam-flowmeter.asp.


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