Transient blade row simulations in turbomachinery are needed either to improve the aerodynamic performance predictions or because the flow interaction we are trying to resolve and predict is unsteady in nature such as aeromechanical, aerothermodynamic or aeroacoustic interactions. Because the blade pitch is not similar between the rows of turbine or compressor, a transient blade row simulation will usually require the modeling of the full wheel (or full geometry). This constraint renders these simulations not practical and in many cases prohibitive as analysis or design tools. Continue reading
For the past few weeks, the ANSYS blog has published many posts and ANSYS has held a number of webinars describing the advantages that ANSYS 17.0 provides for turbomachinery simulation. In the following, I will review these events and provide my summary of 10 (out of many more) exciting developments:
- A focus on HPC delivers significant speedups and ability to handle larger models, for both CFD and mechanical simulation.
- A new mechanical model simulates journal bearings, additionally providing important inputs of stiffness and damping for rotordynamics simulation.
- Fracture analysis is faster and easier with arbitrary crack surface definition and post-processing.
Turbomachinery designers are under pressure to improve all aspects of turbomachinery performance. That applies not only to aircraft engine developers, who sometimes seem to garner the most attention in the news, but to designers of most other machine types as well. While fuel burn and efficiency targets are most often discussed, these targets must be balanced with a number of other competing and often opposing considerations, such as operating range, reliability, cost, time to market, etc.
Engineering simulation now plays a key role in turbomachinery development. This has come about because of significant improvements in engineering software and computing speed. Many turbomachinery companies were early adopters of simulation; they played a significant role in shaping software development to their needs and validating it for their applications. Experiment and testing still play an important role, but often only when a design is sufficiently evolved, or in situations where fundamental information is missing. So simulation and testing complement one another. Continue reading
As you have probably heard, in January of this year, ANSYS 16.0 was released with a full set of new features and exciting enhancements covering our entire simulation portfolio (see more here). But in this blog, I would like to tell you a little more about turbomachinery blade row flow modeling capability in ANSYS 16.0.
Transient blade row (TBR) simulation is an important analysis and design tool, enabling turbomachinery designers to reliably improve the performance and predict the durability of rotating machinery. Traditional transient simulation methods are expensive since it requires simulation of all blades in the full 360 degrees to accurately account for the pitch difference between adjacent blade rows. However, ANSYS CFX pitch-change methods resolve this challenge by providing time accurate unsteady turbomachinery flow simulations on just a small sector of the machine annulus (typically simulating only one or a few blades, a reduced blade row model), thus tremendously reducing computing cost resources and and reducing the overall time to obtain the simulation. Continue reading
At ANSYS, we are continually improving our turbomachinery simulation capabilities. Some recent improvements are proving useful to engine manufacturers, enabling them to better understand the on-wing performance of their new fuel-efficient engines.
Fans in modern aircraft engines are very important in that they provide most of the thrust required by the aircraft. Their environment is very challenging though as they are frequently subjected to non-uniform inflow conditions. These conditions could be either due to flight operating requirements such as take-off and landing, the engine nacelle installation configuration, wake interference from aircraft fuselage or cross-flow wind conditions. Similarly, industrial land-based gas turbines in power plants can be subjected to inlet flow distortion due to upstream ducting or installation maintenance deterioration. Continue reading
Turbomachinery — turbochargers, compressors, jet engines, gas turbines, pumps, etc.— are subjected to some of the harshest environments for an engineered product. High rotational velocities and extreme temperatures and pressures produce high static stresses. Couple on top of that the vibrations encountered due to the fluctuating and turbulent flow field, rotating turbomachinery components are primed for high-cycle fatigue (HCF) failures.
Traditionally, cyclic modal analyses are used to extract the vibrational modes and the appropriate modes from Campbell and interference diagram assessments are scaled based on past test data to arrive at estimates of the vibratory stresses for a fatigue analysis. Continue reading
ANSYS Advantage Volume VII Issue 3 is now available, and I am pleased to announce that the spotlight is on my area, turbomachinery (some call it rotating machinery). My industry colleagues at ANSYS and I contributed several overview articles that, I hope, explain the work we are doing to empower developers to design and build better, more energy efficient turbomachinery.
Of great interest to me are the customer contributions — for a number of reasons, including historical ones. I have worked in the business for so many years, and it is really gratifying to see how far the software and customers’ applications have advanced. The positive impact on new machinery development is amazing as well. Continue reading