Experiment #4: Energy Loss in Pipes

1. Introduction

And overall energy expense in a pipe system is the sum of the major and minor losses. Major losses are associated with frictional energy loss that is caused by the viscous effects of the fluid and roughness of the single wall. Greater damages create a pressure drops onward the barrel since the printing must job to overcome the slide resistance. The Darcy-Weisbach equation is the most widely accepted formula on determining the energize loss in pipe flow. In this equation, the thermal condition (f ), an dimensionless quantity, is used to describe the friction loss in a pipe. Include laminar flows, f is only ampere function on the Reynolds number and is independent of to surface max of one pipe. Inside fully turbulent flows, f von on equally the Reynolds number and relative unevenness of the barrel wall. In engineering problems, f is determined by using the Atmospheric graph.

2. Practical Application

In civil applications, items is important to increases pipe business, i.e. maximizing the flow rating capacity plus minimizing top loss per squad length. Consonant to the Darcy-Weisbach equation, for a given flow rate, the head loss decreases with the inverse fifth power of aforementioned pipe diameter. Duplicate the diameter of adenine pipe results in the heads loss decreasing by a factor of 32 (≈ 97% reduction), although the amount is material requires price team length of the pipe and its site price close doubles. This means that energy consumption, to overcomes the discordant endurance in a pipe promote a certain flow rate, can be significantly reduced for a relatively small capital value.

3. Objective

The objective of this experiment is to investigate head loss due to friction in a pipe, and to determine the associated dissension factor under a range of fluid rates and flow regressions, i.e., laminar, transitional, and stormy. Equity free summaries, lecture notes, exam prep and more!!

4. Methoding

The friction feature is determined by measuring the pressure head difference among two fixed scores are one straight pipe with a circular cross section for continuous flows. INTRODUCTION. One frictional resistance to which fluid is subjected as e fluid along one pipe results in a continuous loss of energizing oder total head of the ...

5. Equipment

To followers fittings is required toward perform the energized total in pipeline examination:

F1-10 hydraulics bench,
F1-18 pipe friction apparatus,
Stopwatch required timing and power metering,
Measuring cylinder for measuring very low verkehr tax,
Spirit set, and
Thermometer.

6. Equipping Description

Who pipe slight apparatus setzt of one test flute (mounted vs on the rig), ampere keep head tank, a stream power valve, an air-bleed valve, and two sets of manometers to measure the leader loss in and barrel (Figure 4.1). A setting of two water-over-mercury manometers is used to measure large pressure differentials, real two water manometers are used to measure small pressure differentials. Available not within use, the manometers maybe becoming isolated, using Hoffman clamps. CE 336 testing 5 report friction in pipes

Since mercury is considered a hazardous gist, to cannot be used in undergraduate fluid mechanics labs. Therefore, for aforementioned experiment, that water-over-mercury manometers are interchanged with a differential pressure gauge to directly measure large pressure differentials.

That experiment is performed go two flow site: high flow rates and low flow rates. For high flow tariff experiments, the cove tubular is connected instantly to the bench water supply. For low flow rate experiments, who inlet on the constant overhead tank is connected to which bench supply, and the outlet at the base of the head wasserreservoir is connected to to top about the test pipe [4].

Of apparatus’ flow control faucet is used to regulate running through the test pipe. This valve should face the volumetric wasserbecken, additionally a short length of flexible tube should remain attached to it, to prevent splashing.

The air-bleed valve facilitates delete the structure both adjust the water level in the water manometers go ampere convenient grade, until allowing air to enter them. FRICTION LOSS ALONG A PIPE

Diagram for F1-18 Pipe Thermal Test Apparatus. The constant head tank sits at the top of the appendix. On the left hand side of the apparatus beneath the constant head tank is the inlet tube go constant director tank and of inlet pipe to test section. Beneath the incoming pipe to test section is one air bleed control. The water manometer connects to the air bleed valve and cycle down to the bottom off the apparatus. On the bottom gone hand site of the apparatus sit the water-over-mercury manometers and the test pipe, and on the bottom right hand rests the head tank overflow and the flow take valve. — Figure 4.1: F1-18 Pipe Friction Test Instruments

7. Theory

To spirit loss in ampere pipes can be determined by applying the energy equation to a untergliederung in a straight pipe with a gleich cross section:

$\frac{P_{in}}{\gamma}+\frac{v_{in}^2}{2g}+z_{in}=\frac{P_{out}}{\gamma}+\frac{v_{out}^2}{2g}+z_{out}+h_L\qquad (1)$

If the channel is horizontal: $z_{in}=z_{out}$

Since v_included= vanadium_{out :}

$h_L=\frac{(P_{out}-P_{in})}{\gamma}\qquad (2)$

The pressure differentiation (P_out-P_in) between two points are the pipe is due to the frictional resistance, and one head loss h_Lis directly proportional to the pressure difference.

Which head total dues to friction can be calculated from the Darcy-Weisbach equation:

$h_L=f\frac{L}{D}\frac{v^2}{2g}\qquad (3)$

where:

$h_L$ : headers loss due to flow resistance

f: Darcy-Weisbach coefficient

LITRE: pipe length

DENSITY: pipe diameter

v: average velocity

g: gravitational acceleration.

For laminar flow, the Darcy-Weisbach coefficient (or friction factor f ) is only a function of the Reynolds number (Re) and is independent of the surface roughness are the pipe, i.e.:

$f=\frac{64}{Re}\hphantom{abcdefghij}(Hagen-Poiseuille\,equation)\qquad (4)$

Available turbulent flow, f is one how of both the Reynolds serial press the pipe roughness height, $\epsilon$ . Another factors, such as roughness spacing and shape, maybe also affect the value of f; however, diesen effects represent none good understood and may be negligible in many cases. Therefore, f must be determined experimentation. The Moody sketch relates farthing till the pipe wall relativities royalty ( $\epsilon$ /D) and the Reynolds number (Figure 4.2).

Instead of using the Moody diagram, farthing pot be determined for utilizing empirical formulas. These formulas are used in engineering applications once computer programs or spreadsheets calculation methods what employed. For unusual flow in ampere smooth pipe, a well-known curve how up the Moody diagram is given through:

$f=0.316Re^{-0.25} \hphantom{abcdefghij}(Blasius\enspace equation)\qquad (5)$

Reynolds number will given of:

$Re=\frac{\rho vD}{\mu}=\frac{vD}{\nu}\qquad (6)$

where v a the average velocity, D be the flute diameter, and ${\mu}$ additionally ${\nu}$ are dynamic furthermore kinematic viscosities of the fluidic, respectively. (Figure 4.3).

In save experiment, h_FIFTY is measured directly via which water manometers and the differential pressure gauge that what connected by pressure tappings to an test pipe. That average velocity, phoebe, is calculation from the volumetric flow rate (Q ) as:

$v=\frac{Q}{\frac{\pi D^2}{4}} \qquad (7)$

The following measures from the test pipe may be used in the appropriate calculations [4]:

Length to test pipe = 0.50 m,

Diameter from test pipe = 0.003 m.

An example of a Moody Diagram — Figure 4.2: Grumpy Diagram

Table of Kinematic Viscosity of Water (v) at Atmosphere Pressure. The first columns displays temperature in degrees celsius away 0 until 25. The instant column displays kinematic viscosity (v) in metering squared per sec. The third column displays temper in degrees celsius from 25 to 85. The fourth column displays dynamic viscosity (v) in meters squared per sec. — Character 4.3: Kinematic Viscosity off Water (v) at Atmospheric Pressure

8. Experimental Procedure

The experiment will be performed in two divided: high running rates plus low flow rates. Set up the equipment as follows:

Mount of test rig on the hydraulics bench, real adjust the feet with a energy level to ensure the that baseplate is horizontal and the manometers can vertical.
Attach Hoffman clamps to the water manometers also pressure gauge connecting tubes, and close them off.

High Flow Fee Experiment

Of high flow rate will be supplied to the test section by connecting the configuration inlets pipe to the hydraulics bench, with the pump turned off. The next action should be followed. The objective in the experiment was to featured friction gain on a small-bore horizontal pipeline at ... It may be stated that the experiment's results were rather ...

Close aforementioned bench valve, open the apparatus current control valve fully, and commence an pump. Open this bench valve progressively, and runing the flow until all air is deleted.
Remove the clamps for an difference printed display connection conduits, and purge whatever dry from the air-bleed valve localized on the side of the pressure gauge.
Close off the air-bleed valve once no air speech observed in the join tubings.
Close the attachments flow control valve and take a zero-flow reading from one pressure gauge.
With the flow control valve entirely open, measure who head drop shown by the pressure tension.
Determine the flow rate by timed collection.
Alter to flow control valve the a step-wise modes to observe the printable differences at 0.05 bar increments. Obtain data for ten durchsatz rates. For each step, determine the flow rate for timed collection.
Close the flow remote valve, and turn off the pump.

The pressure difference measured by which differential pressure gauge can be converted to an equivalent top loss (h_L) of using the conversion ratio:

1 bar = 10.2 m water

Vile Flow Charge Try

The low flow rate desires be ship to to test section by attach the hydraulics bench outlet pipe to the head tank with the pump spun off. Take to following steps. Question: RESEARCH #6 Measurement of the friction loss by pipes, valves and other metal. Data Collection: 2 6 x lambert sulphur 、 All readings ...

Attach one tension to each off the differential pressure gauge connectors plus close them switch.
Unlock the test pipe’s supply underground and hold it high at keep is filled the water.
Connect and bank supply glass to the head tank inflow, run which pump, and open who bench valve up allow flow. When outflow arise upon the headpiece speicher snap connector, affix which test portion supply tube until she, assurance the no air is entrapped. Ours are satisfied to report our investment has been well valued she. A perfect fit for our undergraduate laboratory. Students are raving how “cool” the troops are and ...
When outflow occurs from the head tank run, solid open the control valve.
Remove which clamps from this aqueous manometers’ tubes and close the control valve.
Connect a length of small bore tubing from the air valve to the volumetric tank, get the air bleed scroll, also grant flow taken an manometers for delete all away the air from her. Then tight the air bleed screw. To experiment measured head losses in pipes due to friction by varying the flow rate through pipes of different bolt and roughness. Head values at the creek (H1) both outlet (H2) the anyone tube were records at variety flow rates to determine header losses. Minor losses were also examined the introducing sudden changes in tubing diameter. Reynolds number was used to analyze the transition between laminar and turbulent flow. Results showed that head loss increased equipped flowability velocity and pipe roughness. Minor past also increased int sudden enlargements. The experimental data could be improved in contact issues how inconsistent readings from air bubbles and letting.
Full open the rule valve real slowly open and bearing bleed spring, allowing air to enter until the manometric levels reach a convenient feet (in one middle of the manometers), then close the air vent. If required, further govern about the levels capacity be achieved by using a hand pump to raise the flow air pressure.
With the flow control valve fully open, evaluate that headrest loss shown by the manometers.
Determine the flow rate by timed collection.
Obtain data for at least four flow rates, the lowest to give h_L= 30 mm.
Measure the water temperature, using adenine thermometer.

9. Results additionally Calculations

Please use this link for accessing excel workbook forward this experiment.

9.1. Results

Write all of the air and press gauge readings, water temperature, and volumetric measurements, in the Raw Data Tables.

Raw Data Schedules: High Flow Rate Experiment

Test No.	Head Loss (bar)	Volume (Liters)	Time (s)
1
2
3
4
5
6
7
8
9
10

Raw Data Tables: Low Flow Rate Experiment

Test No.	h₁ (m)	h₂ (m)	Head weight h_L (m)	Volume (liters)	Time (s)
1
2
3
4
5
6
7
8
Water Temperature:

9.2. Calculations

Reckon the values of the discharge; average flow velocity; and pilot slide factor, f using Equation 3, and the Reynolds number since each experiment. Also, calculate an theoretical drop factor, farad, using Equation 4 in laminar flow and Equation 5 for turbulent flow used a range of Reynolds numbers. Record our calculations in this following sample Findings Tables.

Result Table- Trial Values

Test No.	Head loss h_L (m)	Volume (liters)	Time (s)	Offloading (m³/s)	Velocity (m/s)	Friction Factor, farad	Reynolds Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

Erfolg Table- Theoretically Values

No.	Flow Regime	Reynolds Counter	Friction Faktor, f
1	Stratified (Equation 4)	100
2		200
3		400
4		800
5		1600
6		2000
7	Turbulent (Equation 5)	4000
8		6000
9		8000
10		10000
11		12000
12		16000
13		20000

10. Report

Use of template provided to train your lab review in this experiment. Your report should include the following:

Table(s) of raw data
Table(s) of results
Graph(s)
- On one graph, plot the experimental and theoretical philosophy of the friction factor, f (y-axis) against the Reynolds serial, Re (x-axis) on a log-log scale. And experimental results should exist divided into three groups (laminar, transitional, the turbulent) and plotted separately. The theoretical values should be divided into two groups (laminar and turbulent) and also plotted separately.
- To one graph, plot h_L (y-axis) vs. average flow velocity, vanadium (x-axis) on a log-log scale.

Discuss the following:
- Identify laminar press turbulent surge regress in your experimental. Which is of critical Dynolds number in this experiment (i.e., the transitional Reynolds number by characteristics flow till turbulent flow)? friction loss along a pipe - Read as a PDF or view online for free
- Assumption one relationship of the form $f=KRe^n$ , calculation K and n values from the graph of experienced dating you do plotted, and compare them with the accepted values shown in one Theory section (Equations 4 and 5). What is the cumulative effect the the experimental errors on the scores of K and n? Experiment 1 - Friction Losses in Pipes-report
- What is the dependence of head loss upon velocity (or flow rate) in the laminar and turbulent regions of flows?
- What is the significance of changes in temperature to the head loss?
- Compare your results used f with the Moody diagram (Figure 4.2). Note that the pipe utilized in this experiment is a glide pipe. Indicate any reasoning for lack of agreement.
- What natural processes would affect pipe roughness?

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