Rotating Machinery

ANSYS CFX is a leading CFD code in this demanding industry, in which the requirements in terms of accuracy, robustness and speed are among the highest. Over two decades of experience in rotating machinery simulation has ensured that ANSYS CFX software provides all the models and infrastructure for accurate, robust and efficient modeling of all types of pumps, fans, compressors, and gas and hydraulic turbines.

ANSYS provides a wide range of products for turbomachinery design and analysis, including rapid optimization of preliminary designs based on 2-D through-flow analysis using the ANSYS Vista TF tool as well as the turbomachinery-specific geometry and mesh-generation tools ANSYS BladeModeler and ANSYS TurboGrid. In addition, tight connection to ANSYS structural mechanics solutions allow fluid–structure interaction (FSI) to be captured whenever required.

Within ANSYS CFX, tailored pre- and post-processing tools complement a full suite of interface models to capture the interaction between rotating and stationary components.

The transient rotor–stator capability resolves the true transient interaction between components for maximum accuracy. It can be applied to individual pairs of blade passages or to the entire 360-degree machine. Setup and use is as simple as it is with the other frame-change models, and it is possible to combine transient and steady-state frame change interfaces in the same computation. Complementing this is the inclusion of second-order time differencing, which delivers greater transient accuracy. Furthermore, transient blade row (time and Fourier transformation) models allow for the simulation of multi-rows, unequal pitch systems using only a few blade passages and less that the full 360-degree geometry.

The stage interface model is a simpler model that provides faster solutions than the full transient rotor-stator model. It enables a steady-state computation to be used by performing circumferential averaging of the variables at the interface.

Various options are available to accurately capture transient interaction between rotating and stationary components. This includes a selection of transient blade row interaction models for modeling the interaction between components in which the number of blades is unequal and, therefore, the pitch-wise extent of the geometrically periodic blade passages is also unequal. This powerful set of models allows significantly faster solution times with reduced-memory requirement compared to transient simulations of the full blade rows.

Another way to model the interaction of rotating and stationary parts is with ANSYS CFX software's frozen-rotor model, which is useful when the circumferential flow variation that each blade passage experiences is large during a full revolution. With this option, computations are performed in a steady-state mode, based on the assumption of quasi-steady flow around the rotating component at every rotation angle. The additional rotational effects (Coriolis and centrifugal terms) are included in the rotating regions, and the frame change across the sliding interface is accommodated automatically when linking the different regions of the solution.

Streamlines shown in cross section through energy recovery turbine of HPB