SpinOffs

This blog article is a follow up for the earlier blog “Coupled Optimization of Preliminary Design Geometry of Low Flow  Steam Turbine with Curtis Stage Layout and Rankine Cycle Parameters”, which considers more complicated case  of coupled optimization of regenerative Rankine cycle and 2 stage turbine geometry with change from partial to full admission flow.

Designing turbines for low flow Rankine Cycle for steam is challenging due to their small size, manufacturing restrictions, clearances and cost constraints. Such turbines operate at significant pressure ratios that require use of partial admission and are likely to operate in choked supersonic flow mode due to reduced stage count (controlled by cost).

The previous blog, Entropy Happens… Deal with It! ended with the statement, “That’s how Concepts NREC deals with the constraints of the Second Law of Thermodynamics when designing high-efficiency turbomachinery – we literally put entropy to work!” That blog not only lead to an increase in sales of bumper sticker sales emblazoned with “Working on it, STAY TUNED!”, it led to a request to explore this statement in a little more detail – particularly as the idea might apply to the analysis, design and manufacturing of turbomachinery.

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.

If there’s one thing good about sitting in snarled traffic in Boston, it’s that you get to see some very original bumper stickers. The most recent bumper sticker I saw was probably the strangest one, no doubt created by some engineering professor who doesn’t see that the glass is half full, but that it has a safety factor of 2! Nevertheless, the bumper sticker stated the obvious when one thinks about it: ENTROPY HAPPENS! And then, to emphasize the point, the artist has the letters slowly “evaporating,” demonstrating graphically that entropy proceeds from order to chaos.

Wow, Concepts NREC had a lot going on at this year's ASME Turbo Expo 2019 in Phoenix, AZ! We held our North American CAE User Group Meeting, spoke to over 200 people at our booth, chaired several sessions and presented two papers. In case you were not able to go, here are the abstracts from the two papers: