SpinOffs

If you design turbomachinery for a living, you are already doing multidisciplinary optimization (MDO), regardless of whether you have a special software tool with MDO built in or not. Turbomachines, by their nature, require advanced fluid dynamics as well as very high mechanical complexity.  Whenever you make a trade-off between performance and durability or performance and weight/inertia, you are doing an MDO study. Adding MDO software to your traditional design approaches can give you additional insight into the trade-offs, and save you time by avoiding the need for manual iteration.

Valentine’s Day is February 14, and while some cynics refer to it as a “Hallmark holiday”, most people commemorate the day in some way. One of the biggest challenges is finding a card that perfectly captures the way you feel about someone, while also reflecting who you are.  Well, Concepts NREC has created some turbomachinery-themed Valentine’s Day cards for engineers. These fall into the Art end of our Art-to-Part Solution.

Years ago, I got a pocketknife as a gift, and I absolutely loved it, still do. It came in handy during my college years, when I was really into camping and trekking. As the years went by, it stayed relevant to my new interests, such as motorcycle trips and surfing. It has helped me open cans, remove sea urchin spurs, and install shelves in my apartment. It has also saved me time and money on several occasions by fixing my bike. It is incredible how tightening some screws and pulling some wires can save towing costs – and a sunny day.

Most turbomachines need to operate across a range of fluid flow rates and speeds. This is obvious in transportation applications where gas turbine engines and turbochargers need to operate at all of the speeds, altitudes and temperatures that the vehicles they power will encounter. In industrial and refrigeration applications, turbomachines need to have a wide operating range to make them appealing to end users who want efficiency under many operating conditions.

Frequently, there is a need to reconstruct 2D and 3D geometry from reported or measured surface data points. In most cases, the provided surface data include significant amounts of noise for various reasons, including quality of the scanned blade, deviations produced by the measurement system, curve digitization errors, data digital rounding and truncation, and errors in reporting the data.  This noise hampers quality surface reconstruction and masks the understanding of the design intent of the profiles.  It also affects the accurate representation of the geometry, manufacturing complexity, and aero performance which forms the basis on which a design engineer can execute any design improvements.

Many energy recovery, drive cycles (Organic and Steam Rankine cycles) and rocket propulsion cycles require the use of a turbine that operates at low volumetric flow and high-pressure ratio. Additional requirements include low cost, reduced weight, and reduced axial length (for robust rotor dynamics).

Many gas turbines with radial compressors utilize a radial-to-axial inlet duct upstream of the first compressor stage. Aside from the fact that flow in the duct generates aerodynamic losses, the flow profiles at the duct exit, delivered to the inlet of the first impeller, also affects the performance of the compressor. 

High-efficiency, low-cavitation pumps often require a screw type inducer to treat the inflow to the main radial/mixed flow pump blades. Efficiency and head rise, split between inducer and main pump, are questions explored during the design process. Another important design consideration is the tolerance to cavitation. Finding the best solution, when there is often a trade-off between two or more operational conditions, is difficult. We have found that multi-objective optimization, for single or multiple operating points, is the best tool to use.

Engineers, by their very nature, like to design new things. To us, there is an undeniable appeal to creating something no one has ever seen before. However, there are compelling reasons to leverage your company’s past. It can be far more cost-effective and less risky to re-use past successful designs.

Finding the root cause of a failure by narrowing down multiple overlaid symptoms can be a long and tedious process—and very often the true underlying problem is not what one might expect by a casual examination of the symptoms. That was the potential difficulty a customer of ours wanted to avoid when they investigated the catastrophic failure of a super-critical, feed-water pump used for a powerplant boiler.