In the design of radial turbomachinery impellers, such as centrifugal compressor or pump impellers, splitter blades are often used to ensure good aerodynamic/ hydrodynamic performance without compromising flow range. In the case of pumps this is necessary to achieve good suction performance.
Blade lean is commonly used in the design of axial turbine nozzles to reduce endwall losses and to obtain a more uniform exit flow distribution. Numerical and experimental investigations have shown that the use of blade lean, whether straight or curved, in the conventional design practice merely redistributes the losses in the blade and does not result in a reduction in loss. This is partly because in conventional design the blade profile is kept the same and the stacking line is changed to achieve the blade lean.
The flow in centrifugal compressor impellers is dominated by secondary flows which result in the formation of the impeller exit non-uniformity (the so-called “jet-wake flow” effect). This can be clearly seen in Figure 1, which shows the three-dimensional CFD prediction for a state-of-the-art conventionally designed impeller.
The design of the vaned diffuser of a centrifugal compressor is still based on a considerable amount of empiricism in its design methodology. Parameters such as area ratio and blockage, which are more relevant to conical diffusers, are used in conventional design practice.
Design Target To develop a high performance 3 stage axial LP turbine in a 6 weeks period time frame to help in a competitive bidding process with other competing aeroengine manufacturers.
Deliverables High performance LP turbine developed within 5 weeks.
Impact The high performance of the turbine enabled the client to beat other major aeroengine manufacturers and win the competitive bid. The turbine has already been manufactured and flown in an aeroengine.
TURBOdesign1 has been applied to the design of a three-component automobile torque converter. Due to the strong curvature of the flow passages and high loading, the flow behavior is extremely complex and difficult to optimize using a conventional design approach. Using TURBOdesign1, it is possible to achieve the best matching between the components, control secondary flows, and suppress flow separation.