|
|
Today, the design of all types of turomachinery, such as aircraft engines, gas turbines, steam turbines, hydro-turbines, pumps, fans, compressors, and turbochargers, is almost unthinkable without CFD as a part of the design cycle. Moreover, as turbomachinery CFD comes of age, it is being applied throughout the range of flows involved - not only in the main flow path, but also in seals, cooling passages, bearings, bleed off-takes, and a host of related applications. Back in the 1970s, turbomachinery was among the earliest industrial applications of CFD. The primary importance of aerodynamics in the design of compressors and turbines ensured that their designers were among the first to seize upon the exciting possibilities offered by the then-emerging technology. Beginning with simplified two-dimensional calculations of flow between adjacent airfoils, CFD gave engineers new freedom in designing profiles for turbine nozzles, turbine blades, and compressor blades. Their use of this capability made a dramatic impact on the performance of aircraft engines, steam turbines, and gas turbines for power generation. The use of CFD in the development of novel low-loss aerodynamic profiles was later extended to fully three-dimensional blade design. This produced even further improvements in predicting the efficiency and aerodynamic loading range of engines. In the design-by-analysis approach using advanced CFD, it became possible to manage shock strength and position in transonic blading and to control the effects of secondary flow in turbines and compressors.
The use of CFD in aircraft engine fan design has had a huge impact on performance over the last 30 years.Greatly improved efficiency is obtained at higher stage pressure ratios, resulting in large reductions in engine specific fuel burn. If these improvements had not been made, at current levels of air traffic, the required increase in global aviation fuel consumption would be worth billions of dollars annually. This level of savings can be attributed to CFD being applied to aircraft turbomachinery.(click image for enlarged view) More recently, it has become possible to use CFD to investigate and exploit the interaction of fixed and moving blade rows in integrated stage design. This can be used not only for optimal tuning of aerodynamic performance, but also to estimate the dynamic forcing of blade vibration due to the relative motion of the blades. A further example of the application of unsteady methods is the dispersion and effectiveness of turbine cooling flows from upstream blade rows. CFD is used in the development of many aspects of turbomachinery flow. Diffusers, intakes, guide vanes, valves, and exhaust collectors can all be analyzed in detail. Even in gas turbine combustion chambers, where chemical reactions are strikingly complex and where heat release from the reacting and adjacent turbulent flow streams combine to dominate the flow physics, CFD now plays an important role in the engineering process. The powerful CFD technology that has enabled the rapid pace of progress in aircraft engine performance is now in widespread use throughout the world of flow machinery. FLUENT's flexible and powerful solver technology is the basis for design decisions made not only in some of the world's leading gas turbine manufacturers, but also in companies supplying fans for domestic ventilation and appliances, pumps for the oil and water industries, and fluid moving equipment of all shapes and sizes. The benefits of CFD in the analysis of this type of equipment are clear:
In these industries, where aerodynamic performance is a "crown jewel" technology, and where only CFD can deliver the improvements being sought in a practical fashion, the impact of the successful application of CFD on business is substantial. Therefore, it is not surprising that many industry leaders have shifted their emphasis from physical modeling and trial-and-error troubleshooting to CFD-based strategies. |
FluentNEWS |
||
 |
|
|
|
