SpinOffs

Aerodynamic blockage is a comparatively simple parameter to measure and reveals important aerodynamic performance data. Aerodynamic blockage is directly related to the displacement thickness concept of boundary layers. It represents the fraction by which a flow passage is effectively “blocked” by the presence of the low momentum boundary layer regions. If an analyst knows the aerodynamic blockage, the boundary layer displacement thickness can be directly computed, and vice versa, if the boundary layers are uniform across the passage cross section.

Every company in the turbomachinery industry needs robust technical expertise to survive in this very mature business. Whether you make a rotating component or use one in a product, your in-house engineers have to consider many factors when designing a product. They must find the appropriate balance between the competing factors of higher efficiency, lower cost, ease of manufacturability and increased performance. Doing this task well requires insight across many disciplines. It also requires a deep understanding of the impact the various trade-offs made on the product and your bottom line.

Three-dimensional flow fields typically have some degree of distortion in the flow properties and flow profiles across a given cross section. These distortions can be quite significant in regions that include the exit plane of the impeller. Because most designers are interested in averaged values of performance, the question often arises as to what averaging technique is the best to use.

One of the most important design choices facing a chiller compressor designer is whether to utilize open or shrouded impellers. The impacts of this verdict are wide ranging, which arguably makes this most basic selection the most critical one.