Use the PIPE-FLO® software to determine the pressure drop in 100 m of horizontal DN 50 Schedule 40 pipe, carrying 25°C water at a velocity of 4 m/s. Report all applicable values related to the solution such as Reynolds number and friction factor.

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1. Open a new project in PIPE-FLO® and select the “System” menu on the toolbar to initialize all key data such as units, fluid zones, and pipe specifications.

2. The “Units” menu allows us to choose how we want to define our units for the entire piping system.

For this problem, select the typical SI units as shown below. Note that PIPE-FLO® defaults to English units at the start of a new project, but any units can be selected through this menu. The units for any individual parameter can be easily changed via drop down at any time when working with the model.

3. The “Fluid Zone” menu allows us to define what fluid we wish to use in our system. All problems worked with PIPE-FLO® in this text will comply with the demo version constraint of a single fluid zone, meaning one fluid in the system. Under the “System” menu, select “Fluid Zone”, then “New”, then “Water.” Upon selecting a fluid in the box on the left, and entering our initial temperature and pressure information, PIPE-FLO® will fill in the remaining information based on its internal database, reflecting the values we would manually look up in the appendix of this text or outside references. This database approach to properties is both convenient and powerful, also allowing us to edit a fluid’s state, such as its temperature, and all associated properties are automatically updated. For this problem, enter 25°C and 101 kPa(abs), which designates atmospheric pressure. Note that in PIPE-FLO®, absolute pressure is written as “kPa a”. We can also rename our fluid for clarity and convenience. Rename this fluid zone “Water @ 25C”, as shown, which will be important later in this example.

4. Now designate the type of pipe. For this problem, click “New” on the main pipe specification menu, scroll to “Steel A53-B36.10” to indicate commercial steel pipe, and then the number “40” to indicate the schedule. Be sure to use the small triangle to the left of the words to expose the pull-down menu that lists the various schedules available. The roughness factor shown corresponds to values shown in Table 8.2 in this chapter. Note that for special cases, the user can simply enter a roughness factor directly. As with the fluid zones, the pipe names can also be changed, shown in the example below as “Schedule 40”. You will note that we haven’t chosen a size for a particular pipe yet and there is no option to do so under this menu. We will complete the pipe size later in the problem. Here we simply establish the pipe type.

Material	Roughness [latex]\epsilon[/latex] (m)	Roughness [latex]\epsilon[/latex] (ft)
Glass	Smooth	Smooth
Plastic	[latex]3.0 imes 10^{-7}[/latex]	[latex]1.0 imes 10^{-6}[/latex]
Drawn tubing; copper, brass, steel	[latex]1.5 imes 10^{-6}[/latex]	[latex]5.0 imes 10^{-6}[/latex]
Steel, commercial or welded	[latex]4.6 imes 10^{-5}[/latex]	[latex]1.5 imes 10^{-4}[/latex]
Galvanized iron	[latex]1.5 imes 10^{-4}[/latex]	[latex]5.0 imes 10^{-4}[/latex]
Ductile iron—coated	[latex]1.2 imes 10^{-4}[/latex]	[latex]4.0 imes 10^{-4}[/latex]
Ductile iron—uncoated	[latex]2.4 imes 10^{-4}[/latex]	[latex]8.0 imes 10^{-4}[/latex]
Concrete, well made	[latex]1.2 imes 10^{-4}[/latex]	[latex]4.0 imes 10^{-4}[/latex]
Riveted steel	[latex]1.8 imes 10^{-3}[/latex]	[latex]6.0 imes 10^{-3}[/latex]

5. With all system data initialized, start building the system. There are many ways to model a horizontal pipe with flow to determine the pressure drop. Here let’s do so with a supply tank at one end, and a “Flow Demand” at the other. Click and drag a “Tank” from the toolbox on the left, to the open background referred to as the FLO-Sheet®. We are using this tank as an arbitrary pressure source to model our horizontal run of pipe. Click on the tank on the FLO-Sheet® to display the “Property Grid” on the right-hand side of the page. Enter a tank elevation of 0 m, a surface pressure of 750 kPa, a liquid level of 10 m, and the fluid zone that we earlier named as “Water @ 25C”. Note that these values are arbitrary for this problem because we are simply asked to compute the pressure loss over 100 m of pipe. More detail about these individual settings will be explained in future sections of the text as more complete models are built. Note that the default tank icon shows an open tank. Change that icon to a pressured tank by selecting “Symbol Settings” in the property grid and choosing a closed tank icon as shown below. Again, more detail will be given later with more complete system models, but note now that icons should be changed when necessary to more accurately reflect the model being built. An open tank icon, for example, should not be left to represent a pressurized tank.

6. Next, add the pipe to the model. Choose “Pipe” from the toolbox menu on the left, click on the tank on the FLO-Sheet®, and drag the pipe to the right and click the FLO-Sheet® again. Don’t worry about initial placement; after the pipe has been placed, we can easily modify its properties similar to the process used for the tank. Choose the same fluid zone. Choose the type of pipe established earlier, and specify size. This problem calls for DN 50 Schedule 40, and the actual size can be verified by dropping down the “Size” column in the property grid which shows the pipe I.D. as 52.5 mm. Enter a length of 100 m for this section of pipe. Recall from Chapter 6 that the DN 50 Schedule 40 pipe is identical to the 2-in Schedule 40 pipe.

7. PIPE-FLO® can, of course, build complete systems, but it also provides ways to model segments of a system. In this case we’re interested only in the pressure drop in one run of pipe. Rather than model components downstream, simply enter a “Flow Demand” at the end of the pipe indicating downstream flow without requiring any system details. Flow demand is found in the toolbox under the “Basic Devices” section. After placing it at the end of the pipe, we must enter values for the elevation, flow rate, and flow type of the demand. For this example, use an elevation of zero, assuming the pipe is horizontal. Calculate the flow rate corresponding to a velocity of 4 m/s. Enter that flow rate, 520.3 L/min. Since this demand represents flow leaving the system, choose the “Flow out” option under the flow type.

8. The final step in this problem is to calculate the results of the system. Click on the button that looks like a calculator on the toolbar.

To view the information that has been calculated about a particular item on the FLO-Sheet®, choose that item on the property grid under “Device View Options”. Simply check the box of each item you want to display, and they will be shown on the FLO-Sheet® under that particular item. For this introductory problem select all data to be displayed. Note, in order to find the “Device View Options” box in the Property Grid, you must first click on the FLO-Sheet® background and make sure that no system component is selected.

Final results are displayed under the pipe in text form. In this case, the pressure drop across this length of pipe is 309.8 kPa, with a Reynolds number of 236 068, and a friction factor of 0.02 033, resulting in a head loss of 31.68 m.

L = Pipe length
Flow = Volume flow rate, Q

Vel = Velocity of flow, v
dP = Pressure drop, [latex] \Delta p [/latex]
HL = Head loss,[latex] h_L[/latex]
Re = Reynolds number, [latex] N_R [/latex]
ffp = Friction factor, f

Question 8.9: Use the PIPE-FLO® software to determine the pressure drop in...

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