Leveraging AxSLICE for Centrifugal Pump Upgrades and Retrofits

Often, service companies are faced with the challenge of redesigning existing pumps that have failed in the field with extremely quick turnaround times. While there are quick-fix methods to return these pumps into operation, other more complex problems may require taking a step back and analyzing how this particular pump could be redesigned based on its current operation.  These engineering upgrades could solve recurring issues with failure modes of a certain machine, and they could also solve new capacity demands that are imposed by a customer based on their system’s upstream or downstream changes. While efficiency increases could be beneficial to the overall system, many times it is more important to solve capacity requirements and increase the life of the pump by decreasing the Net Positive Suction Head Required (NPSHr).

In this blog post, we will investigate how to move an existing centrifugal pump through the AxSTREAM platform in order to solve engineering challenges seen on common OEM pump upgrades.  With the use of AxSTREAM’s integrated platform and reverse engineering module, many of the CAE tasks that are common in an analysis such as this one can be realized in record speed. The first step of the reverse engineering process occurs in obtaining the necessary geometrical information for the desired pump. Through AxSLICE, the user can take an STL, IGES, CURVE file, or a generated cloud of points and properly transform this 3D profile into a workable geometry inside the AxSTREAM platform. In a matter of minutes, the user can outline the hub and shroud and transform a blank 3D profile into a profile defined by a series of segments.  Seen in Figure 1, the centrifugal pump is now defined by a hub, shroud, and intermediate section.

AxSLICE
Figure 1 – AxSLICE™ Module for Importing Existing Profiles
Blade Impeller Cut-Back on Leading Edge
Figure 2 – Blade Impeller Cut-Back on Leading Edge
Importanted CP Design
Figure 3 – Imported Centrifugal Pump Design into AxSTREAM®

Once the necessary parameters are inputted (rotational speed, number of blades, pressures, mass flow, etc.), the machine is fully incorporated within the AxSTREAM platform and can move onto a number of different modules.  As seen in Figure 2, the profile of the centrifugal pump is now defined by a series of beta and theta curves on each section. The user can also find the thickness distribution defined by the imported 3D geometry and any other important parameters to the blading and its arrangement. At this point, any analysis on the existing design can be performed and saved in a number of different reports and formulations.  Figure 5 shows a streamline analysis of the existing centrifugal pump design. The user can then manipulate the design in order to accommodate higher efficiencies, new capacity demands, different frequency modes, and many more constraints. After these engineering design manipulations, each design can be compared to the existing (or imported) design in order to investigate the improvements of the redesign.

Redesign Pump with Smooth Beta and Theta Distributions
Figure 4 – Redesigned Pump with Smooth Beta and Theta Distributions
Streamline Analysis on Existing Pump
Figure 5 – Streamline Analysis on Existing Pump
FEA Modal Analysis
Figure 6 – AxSTRESS™ FEA Modal Analysis on New Centrifugal Pump Design

This quick manipulation for engineered pumps can be accomplished in the fastest possible time using the only fully integrated platform for turbomachinery design, AxSTREAM.

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