Knowing the Main Features of BOMBAS (PUMPS) Desktop, the Centrifugal Pump Selection Software in Water Pipeline Systems

With PUMPS online we put the centrifugal water pumps selection at your fingertips by allowing that the selection process could be done from any kind of device such as computers, tablets, and mobile phones, provided that an internet connection exists. Everything is in the cloud!

In response to request from several customers, claiming not to be internet-dependent to use this selection tool, we are releasing the desktop (downloadable) version of our centrifugal pump selection web application, including in this version some enhancements such as a results chart customization, MS excel data import/export, among other features.

Let us give you in this tutorial a walkthrough of the features for the desktop version of the simplest Centrifugal Pump Selection Software, for sure you’ll love it.

When BOMBAS (PUMPS) software starts, you will see the PUMPS tab as active, no matter if a project is currently opened or not:


Tools included in this tab are the ones that will allow to create the centrifugal pump catalogue within the software in order to be used in the pump selection process.

The following video shows you the available features in this tab which, we reaffirm, it’s one of the most important within our Centrifugal Pump Selection Software, since it’s a must to count with a minimal quantity of pump models so as to allow the BOMBAS’ projects creation:


The PUMPS tab is the place where your centrifugal pumps catalogue will be kept so on it you will find different features to create and maintain the operating characteristic curves to be used on your centrifugal pump selection process among every project created.

The idea here is that you progressively conform a pump’s database containing the performance data for commercial models of centrifugal pumps and from which you can select the appropriate ones for the purpose of your water pipeline system’s target operating point.

When you run BOMBAS for the first time you will notice that there are no centrifugal pumps models available on the Pump’s List panel, so it is a must that you start to populate the pump’s database.

First thing to do is create an empty centrifugal pump model by clicking the New button on the Pump’s list panel.

In the pumps general properties dialog you must fill each of the provided fields required to identify the current model not only by its name and uses but also by its hydromechanical characteristics.

So let’s enter the manufacturer’s name…

The Pump’s rotational speed in revolutions per minute as well as the impeller diameter.

And finally we’ll select the application(s) that our new centrifugal pump model will have.

Click OK to close the dialog.

The table with the data of the centrifugal pump characteristic curves is now enabled, so we can start to introduce the corresponding values from the actual model performance data.

The most common way, on the basis that the centrifugal pump model manufacturer’s catalog is at your reach, is by entering each characteristic curve data point clicking this button.

Thus, as each data point is created, you will see the characteristic curve evolving in the chart on the right side.

At the end you can visualize, besides the Q vs H curve, the centrifugal pump characteristic curves for efficiencies,

Required Net Positive Suction Head (NPSHr)

And Power…

always having as a reference the pump’s main characteristic curve: the flow-head curve.

In such a case the centrifugal pumps’ performance data is not available, you will find some tools that will allow you to generate your own theoretical characteristic curves, so you can start the pump selection process with no delay.

Let’s create a new pump model in order to introduce you this interesting tools…

First option in the Pump’s Data panel allows you to create the centrifugal pump characteristic curves for head, efficiency, and power by entering the values at the best efficiency point.

To do so, you need to choose among three types of centrifugal pumps, based in its impeller characteristic: radial, Mixed or Axial.

Later enter the best efficiency point values in the corresponding textboxes.

When clicking on the OK button you will see that the head, efficiency, and power characteristic curves have been generated but in the case of the NPSH required, the values are zero because they are dependent on the hydromechanical properties of the centrifugal pump, so they should be provided by the equipment manufacturer (no theoretical approach for this property).

Of course that, based on your own criteria or other references, you can manually enter the values so as to obtain the respective curve.

The second available tool allows you to generate the pump characteristic curve by entering 3 performance points on the pump’s characteristic curve.

Generally it’s recommended that the first point corresponds to the zero flow condition, the second to the BEP and the last one to the maximum possible flow through the pump.

In this case NPSH and efficiency characteristic curves are neither created. So, if they are required, you must manually feed the respective columns.

Finally is the option to apply, to an already existing centrifugal pump characteristic curve, the affinity laws in order to generate a transformed performance curve.

Let’s remove this model from the project and back to the previous one…

We pretend to generate, starting from the 575 mm impeller, the characteristic curves for the same model but with a smaller diameter impeller.

Thus we’ll generate a copy of the current one, renaming it of course.

We’ll try with a 505 mm impeller. Note that, we won’t modify the current diameter since the change will be automatically done once we apply the Affinity Laws button.

So let’s modify the flow, head, and power by clicking this button and entering the new impeller diameter.

Note that it’s also possible here to create the characteristic curves for a different rotational speed in the same pump model.

But in this case we’ll keep the rotational speed and only change the diameter to 505 mm.

When clicking in the OK button you will see the modified data but, remember, the efficiency as well as NPSHr values won’t be changed so you must modify them for those that the manufacturer provides.

Each time a modification is done you will see the saving data button enabled so it’s required to click on it to make changes permanent in the database.

Note that, just as we have told you, after performing the diameter modification, the software has also changed the current model impeller diameter to 505 mm.

Also you will find options for exporting pump’s performance data to an MS Excel file,

as well as to import data contained in this type of file into the software.

When importing data from MS Excel, it is expected that the centrifugal pump characteristic curve data be ordered as you can see here.

Also the Excel sheet’s name must contain the name of the centrifugal pump to import into the database, although you can later modify it.

After selecting the Excel file to import, the software will identify each column title and will require you to assign them to each of the characteristic curves table fields.

In this case they have the same order but, if they don’t, you must assure to adequately perform the columns to fields assignment.

If measurement units of the data are different to the default ones, you must change them in this dialog so the software perform the conversion before inserting the values into the pumps catalog.

Clicking this button you’ll be able to modify, before the data importing, the new pump model properties.

By clicking on the finish button, an information message will be shown indicating the number of imported models. In this case, it was only one, as you can see in the list of pumps.

As you have seen, our centrifugal pump selection software offers several features that will ease the creation of your pumps catalog.

What are you waiting for? Give it a try!


After your centrifugal pump catalogue has been created, it is now possible to start with the pumping pipeline’s components creation in the PROJECT tab:


Remember that BOMBAS (PUMPS) performs the hydraulic characterization of the system: Suction tank – pumping station (with one or more water pumps connected in series or in parallel) – discharge or pumping pipeline – discharge tank, so it’s required that you enter the following data in order to perform centrifugal pumps selection:

1. Pumping Pipeline System’s water levels at Suction and Discharge Tanks.

At both Suction Pipe and Discharge Pipe group boxes, you will find the respective textbox where you must enter the water level at the pumping pipeline system’s end sides (suction and discharge). These levels, by default, are supposed to be water reservoirs with a constant water level.

2. Pumping Pipeline System’s properties at Suction and Discharge sides.

BOMBAS assumes that a pipeline system exists starting from the suction tank, at the respective water level, which will convey the water towards the pumping station in order to supply their pumping pipes.

Similarly, at the pumping station discharge side it is assumed that a water pipeline system will be used to feed the discharge tank at the corresponding water level.

Both pipeline systems can be made up of one or more pipe sections, connected in series, having different geometrical and hydraulic properties.

Thus you will notice, next to each pipeline data table, three buttons:

  • Buttons to add and remove rows (or pipe sections at each pipeline system) to/from the table:
  • Button to specify the quantity and type of fittings, such as valves, elbows, among others, installed on each pipeline system’s pipe section:

3. Pumping Station’s Pipes Characteristics.

When we refer to the Pumping Pipe term, it’s required to think of the pumping station component where some centrifugal pump model will be installed and through which the suction and discharge pipeline systems, previously described, will be interconnected.

Hence, in our centrifugal pump selection software the option is available to include any number of Pumping pipes, each of them having associated one specific centrifugal pump model from the software’s catalog.

Take into account that it is not allowed to have two pumping pipes with the same pump model (since it is possible to enter the quantity of similar pumping pipes).

For each Pumping Pipe within your pumping station it’s required to specify:

    • The type of connection for the pumping station’s centrifugal pump equipment. You can choose from serial or parallel configuration, based on the purpose of your pump selection project.
    • Geometrical (diameter, length) characteristics, Hazen-Williams friction coefficient and installed fittings at pump’s suction and discharge sides.

For pumping pipes the head losses calculation will be always performed by using the local head loss coefficients method, so you will always find the fittings manager button enabled, irrespective of the method currently selected at the Head Losses panel.

  • Centrifugal Pump model and quantity of similar pumping pipes at the pumping station. Here, once selected the centrifugal pump model to install into the pumping pipe, you have the option to set, in the Quantity column, the number of similar to this type items in the pumping station.

Take into account that, in most of the cases, it is standard to use the same centrifugal pump model installed in one or more pumping pipes so as to achieve, when operating in conjunction (serial or parallel association), the pipeline system’s target pumping flow (or pumping head).

Thus in our pump selection software it’s only required to create one pumping pipe per model and, if required, to change its “quantity” in order to obtain the system’s operating point.

In addition, if the pumping pipeline system analysis you are performing with BOMBAS requires you to “turn off” some of the existing pumping pipes, all you need to do is to change its quantity value to zero (0) so as to let the software know that it won’t be included in the pipeline system’s characterization.

When the pumping pipeline system’s data has been entered it’s time to click on the Calculate button in order to perform the hydraulic calculation for the active pumping pipes and corresponding centrifugal pumps.

Of course that the pump selection software will perform the project data verification, looking for situations such as:

  • The centrifugal pumps characteristic curves operating range be consistent with the discharge’s pipeline system: remember that, in order to obtain a solution, the discharge pipe characteristic curve must intersect the pumping system’s characteristic curve.
  • In the case that dissimilar centrifugal pump models (with dissimilar characteristic curves) are being associated (especially for pumps in parallel association) it will be verified that, in effect, the combined operation is possible. Here, once more, the respective characteristics curves operating ranges will be checked against the discharge pipeline system’s ones.

In any case it’s important that consistency exists between the flow-head characteristic relationship of the centrifugal pumps that you have chosen and your pump selection project’s targets, for example: to increase pumping flow or the pumping head or to handle a wide margin of flows, among other hydraulic objectives.


If the pumping pipeline system’s calculation is successfully done, you can activate the RESULTS tab to visualize the system’s characteristics curves as well as the resulting pump flows:


1At the top left corner of the RESULTS tab will be shown the pumping pipeline system’s operating point: the total flow and head.

2Table with the operating point of each of the centrifugal pump models included in the current analysis. Regarding the fields in this table you will see, besides the pumped flow per pump, the corresponding efficiency, required NPSH, Power and the pumping pipes (suction and discharge) flow velocities:


Also, note the value between parentheses next to each pump’s actual efficiency at the previous image. This value indicates how far (in percentage) the centrifugal pump operating point is from the BEST EFFICIENCY POINT (BEP).

A negative value indicates that the operating point is at the left side of the BEP on the centrifugal pump characteristic curve. If positive, it’s located at the BEP’s right side.

This parameter will be useful in your centrifugal pump selection process since it is an indicator of how good (or bad) the pumping equipment operating into the pipeline system is.

3Pumping and pipeline System’s characterization chart. This chart clearly shows the system’s characteristics curves.

Based on the type of centrifugal pumps association: serial or parallel, you will see the characteristic curves for each pump unit, against the discharge pipeline system’s characteristic curve. Of course that intersection between those curves will output the system’s operating point, referred in the point 1 above.

As you can see, now you have at your reach the simplest computational tool to perform the centrifugal pump selection in water pipelines systems.

Please remember that the desktop version’s features are the same of the BOMBAS web application, hence you can also check the tutorials provided for this version in order to obtain more details about each software’s component. Click here to list the available tutorials.

Also, in this video, you can see it in action performing the water pipeline system characterization using pumps in parallel association.