Stringent emission regulations force the gas turbine combustor community to come up with new designs. Lean Premixed combustion (LPM) is gaining popularity to meet the emission regulations. However, lean combustion process is prone to other issues like combustion instabilities and noise.
Self-excited combustion instabilities in a gas turbine play a vital role in the lifecycle of combustor, noise generation and pollutant formation. If the instabilities in the combustor dominate at natural modes, there are risks of resonance that can lead to bursting damage to the combustors. Therefore, it is necessary to understand the combustion dynamics performance of a given lean premixed combustor. Continue reading →
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 →
The main challenge of turbulent combustion simulation is to resolve turbulent mixing together with the chemistry of combustion involving hundreds of molecular species, in a solution time that is compatible with engineering design. Steady diffusion flamelet-based turbulent combustion models have been used for nearly three decades. The computational efficiency of flamelet-based models has been the key to their widespread success in industrial applications. However, increasingly stringent emission requirements continuously push designers to incorporate more finite-rate chemistry effects for the engine simulations in a more comprehensive manner. Continue reading →
Most of Brazil’s offshore resources are in deep waters so Petrobras has fostered substantial expertise to develop these fields. One area of importance is the design of marine vessels to withstand the extreme waves. While the discovery of 50 billion barrels of oil in recent decades has been a boon to Brazil’s economic outlook, the location of the oil has produced challenging engineering problems. Lying hundreds of kilometers offshore under up to 3,000 meters of seawater, 2,000 meters of rock and 2,000 meters of salt, the oil reserves are some of the most difficult to access on Earth. Engineers are systematically using best design practices and computational fluid dynamics (CFD) to increase the safety of marine structures and vessels used to drill and produce oil from Santos Basin fields.
Computational fluid dynamics simulation of an FPSO in extreme waves.
Unsteady methods are becoming increasingly important in turbomachinery design and optimization because they model transient flows and performance more realistically. Unfortunately, using time-accurate CFD simulations to understand these unsteady flows in compressor stages can be computationally expensive. In recent years, ANSYS has been working on methods for modelling the transient flows in turbomachinery stages that require as few as single-blade passages per row but with equivalent accuracy. As a result, engineers can drastically reduce computational time and memory resources by up to 10X. Continue reading →
ANSYS CFD is on the verge of a second renaissance in high-performance computing (HPC). The first, spanning more than a decade, has seen tremendous leaps in both the depth and breadth of HPC capabilities. Depth (or heights, rather) in the size of the scalable clusters — first 1000s, then 10K, and recently 100K core counts — and breadth of coverage across solvers, physics, post-processing, even file I/O, covered the gamut of high-performance simulations. The trend, in fact, is exponential, as evident in this chart, and spans many years of ANSYS Fluent software releases. While there are other impressive scientific scalability demonstrations, ANSYS Fluent set the standard for industrial HPC CFD simulations. Continue reading →
3-D computational fluid dynamics simulation of in-flight icing (3-D CFD-icing) has achieved considerable advances in the last decade , and many dynamic OEMs and second tier suppliers are using them to speed icing certification. Yet, others remain on the fence, using technologies from three decades ago.
The different characteristics of ice, at different locations on an aircraft:
can that be done in 2-D?
Recent innovations in ANSYS 18 overset mesh have made it possible to use computational fluid dynamics simulations to model the smoke tests that provide useful guidance in designing clean rooms.
Ensuring Clean Rooms are Actually Clean
In the healthcare and electronics industries, process contamination is a primary concern. They manufacture these sensitive products in clean rooms where the concentration of airborne particles is controlled to specified limits. For example, a Class 100 clean room keeps particles of 0.5 microns or larger to less than 100 per cubic foot of air. Even in these controlled environments, particles are constantly being created and can settle on and contaminate surfaces and products. Continue reading →
My friend, a fellow Romanian, just told me a funny story. She just relocated to the U.S. and was asking her dentist “When will I have the root channel treatment?”. The dentist kindly replied “Did you mean root canal, my dear?”
Human kindness is a beautiful thing. As a software developer, I often wish that computer programs would be equally technically kind. Most of them are not. Many times, when a user mistypes a command, applications crash.Continue reading →
ANSYS Fluent 18 has advanced erosion fluid dynamics modeling by adding three industry-standard models to the previous default model.
Erosion wear is the loss of material due to repeated impact of solid particles on a surface and causes major economic losses across diverse industries such as oil and gas, hydraulic transportation, and chemical processes. Erosion severely damages flow passages, valves and pipe fittings, leading to higher replacement costs as well as the loss of valuable production time. For example, some oil and gas fittings can fail after just 30 minutes of operation due to high erosion rates! Engineers need to quickly evaluate the erosion on dozens of design variations to find ways of stretching the part’s lifespan in order to reduce costs and maximize process up-time.