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).

I recently got back from my favorite annual conference: ASME’s Turbo Expo. This year, someone thought it would be a good idea to hold it in Phoenix, Arizona…in the summertime.  While that’s not the choice I would have made, I did enjoy the conference very much and thought it was well worth attending. 

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:

Wind power generation is rapidly growing worldwide, and with that growth, demand for wind turbine design engineers is also growing.  However, an engineer who has experience designing turbines in most applications, will often have trouble translating their hard-won skills for general turbine design, into the wind turbine design. Why? 

As one might expect, the temperature of a substance typically increases as energy is added to it. This is the case with most substances in all phases. The exception is when a substance crosses to a different phase, which usually involves no temperature change. The energy difference between these phases is called the “energy of formation”.  

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.

I think we can all agree that designing turbomachinery is hard. There are just so many moving parts (pun intended) in the design process, and they are all interconnected.  When you change the blade shape, it changes the aerodynamics, and could impact manufacturability. Everything you change has a cascading effect across many different areas, because all of the areas are linked; just like a Rubik's^® cube! Only, in turbomachinery design, you are not always trying to get all of the sides to be one color. Heck, even a 3-year old can do that. 

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.