Using a sizing-pump in PIPE-FLO® The pump illustrated in Fig. 11.12 delivers water from the lower reservoir to the upper reservoir at a rate of 2.0 ft^3/s. Both the suction and discharge pipes are 6-in Schedule 40 steel pipe. The length of the suction pipe leading to the pump is 12 ft, and 24 ft

Question

Using a sizing-pump in PIPE-FLO®

The pump illustrated in Fig. 11.12 delivers water from the lower reservoir to the upper reservoir at a rate of [latex] 2.0 ft^3/s[/latex]. Both the suction and discharge pipes are 6-in Schedule 40 steel pipe. The length of the suction pipe leading to the pump is 12 ft, and 24 ft of discharge pipe extend from the pump outlet to the upper tank. There are three standard 90° elbows and a fully open gate valve. The depth of the fluid level inside the lower tank is 10 ft. Use PIPE-FLO® to calculate (a) the pressure at the pump inlet, (b) the pressure at the pump outlet, and (c) the total head on the pump.

Accepted Answer

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 the same way as in the previous example problems using PIPE-FLO® in previous chapters.
Start by placing the tanks in the problem, and filling in their initial data in the property grid.
To insert a sizing pump, choose “sizing pump” from the “pumps” menu in the tool box and place it on the FLO-Sheet®. As stated earlier, the only data requested from the user are the suction and discharge elevation to define the relative position of the pump, and the desired volumetric flow rate. This flow rate can be specified in any form of a volumetric flow rate by double clicking the “. . .” button that appears on the right after selecting the value box for the flow rate. For this specific example, the volume flow rate was given as [latex]2.0 ft^3/s[/latex]. Since the bottom of the lower tank was set at an elevation of 0 ft and the fluid level in the tank was given to be 10 ft, the elevation of the pump suction and discharge would be 20 ft since the pump is shown as being horizontal.
Continue the problem by adding in the pipe sections, elbows, pipe entrance, pipe exit, and fully open gate valve in the same manner as presented in past example problems.
After all components and information have been entered, be sure to turn on the information to be displayed for each component under the “Device View Options” in the property grid.
For the pump in this problem, it is requested that we show total head, suction pressure, and discharge pressure. In Chapter 13, other factors will be called for. The results from the problem are shown below.
Note the following output values:

a. There is a negative gage pressure at the inlet of the pump, −5.23 psig, because the pump must raise the fluid 10 ft from the surface of the lower tank to the suction inlet port of the pump and overcome energy losses in the suction pipe.

b. The pressure at the pump outlet is positive, 14.87 psig. The result is that the pump increased the pressure of the fluid by 20.1 psi which is necessary to elevate fluid to the upper tank and to overcome the energy losses in the discharge pipe, the elbows, and the valve.

c. The total head value for the pump, 46.39 ft, is a measure of the amount of energy that the pump must deliver to the fluid when moving [latex]2.0 ft^3/s[/latex] of water between the tanks for the given piping system. You will learn in Chapter 13 that this is an essential data point for pump selection.

Question 11.8: Using a sizing-pump in PIPE-FLO® The pump illustrated in Fig...

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