Rotor Design Capabilities – AxSTREAM

Introduction

An aerodynamically efficient and structurally sound blading is a must for any turbomachine. However, once the geometry of the blades and the attachment (root, disk, wheel, etc.) has been determined, the design work isn’t quite finished as attention must be brought to the design of the rotor itself. The rotor design iterative process should be conducted in parallel with the full scope of structural checks (such as centrifugal and thermal stresses, gravity sag, burst calculations, etc.) and rotor dynamics analyses. Each attached rotor component (blades, disks, interstage and end packing seals, journal and thrust bearings, etc.) has to be analyzed, properly designed and finally assembled on the shaft at appropriate locations. The AxSTREAM RotorDesign software was created to be an integration platform between all design tools and calculation modules. Following design and analyses steps in AxSTREAM RotorDesign, the complete and highly reliable rotor with all attached equipment can be designed and exported to AxSTREAM RotorDynamics for rotor dynamics analysis and eventually to CAD software for further steps of end product creation.

Design Process

The AxSTREAM RotorDesign tool allows users to import a new/existing/optimized flow path design in order to design the rotor based on AxSTREAM 2D flowpath layout or through a manual input of the blade axial and radial positions when used as a standalone software.

The corresponding AxSTREAM project contains information regarding the blades geometry, material, location, diameters, number, etc. Based on this information, AxSTREAM RotorDesign calculates and prepares all required information for AxSTREAM RotorDynamics and other modules involved in structural checks such as mass and inertia characteristics, loads and boundary conditions.

Flow Path Imported from AxSTREAM

Flow Path Imported from AxSTREAM

The blades (with root and shroud attachments) and disk geometry can be imported from AxSTRESS – AxSTREAM’s 3D FEA tool – where they can be designed. The second option is to model them in a simplified manner within the AxSTREAM RotorDesign module to create the correct rotor model with regards to the loads and equivalent mass-inertia and stiffness characteristics, providing additional constraints in terms of sizing of the rotor for its design.

Roots and Disks Geometry Import from AxSTRESS
                       Roots and Disks Geometry Import from AxSTRESS

Other component designs such as interstage and end packing sealing zones, couplings, journal and thrust bearing positions and thrust bearing positions and appropriate shaft sections (both cylindrical and conical) with chamfers and fillets can also be added in the rotor assembly using the AxSTREAM RotorDesign libraries of standard components or created manually.Each element of the rotor can be assigned to a material from the embedded library or one created by the user.

Once the initial rotor design is ready, the entire rotor model can be exported to the AxSTREAM RotorDynamics module to perform rotor dynamics analyses while accounting for respective sections temperature as defined in the AxSTREAM RotorDesign model. If rotor dynamics and structural criteria are satisfied then CAD export can be performed to get rotor geometry to be used in further design steps. In other cases, the integrated RotorDesign system allows for a quick redesign of rotor components and recalculation of all steps in order to meet requirements.