SpinOffs

   

What's Better than Perfect? Semi-Perfect Gas Models

by Mark R. Anderson on Mar 8, 2019 10:30:00 AM

In a previous blog, Fluid Phenomena Primer: Energy Versus Temperature, Specific HeatI explained the behavior for gas phase fluids and how the temperature is affected at high energy levels.  In another blog, When Perfect is Good Enough - Perfect Gas Models, we looked at the simple perfect gas model.  In this blog, we’ll explore the next step up in the hierarchy of gas thermodynamic modeling: semi-perfect gas.

How the Design of a Wind Turbine Differs from Other Types

by Kerry Oliphant on Mar 1, 2019 10:22:00 AM

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? 

Phase Change - Make Mine a Double!

by Mark R. Anderson on Feb 22, 2019 10:40:06 AM

As I’ve always said, there’s as much thermodynamics in a glass of beer, as there is in a power plant. Don't believe me? Read on. Phase change is common phenomena that we see all the time.  We’re most familiar with H2O, of course, in its various forms: ice, water, and steam. This is partly because it’s a very common substance (on Earth anyway) but also because it’s one of the rare fluid types that readily changes phase at temperatures and pressures humans can typically dwell in. 

 

Back to Beer...

When Perfect is Good Enough - Perfect Gas Models

by Mark R. Anderson on Feb 15, 2019 10:22:00 AM

What is a perfect gas?

A perfect gas is one that has a linear variation in energy with respect to temperature and a linear variation in pressure with respect to temperature at constant volume. The perfect gas model is the simplest of all models for gas phase fluids. For a perfect gas, we need only two unique properties of the substance to determine the relationships between pressure, density, energy, and temperature. 

 

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.

 

Fluid Phenomena Primer: Energy Versus Temperature, Specific Heat

by Mark R. Anderson on Feb 8, 2019 10:10:29 AM

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”.  

Temperature envelopes in the turbomachinery industry are constantly increasing as the state of the art evolves in pursuit of better performance. This means engineers need to design compressors with higher and higher exit temperatures, and turbines and nozzles with continuously increasing inlet temperatures. This rise in temperature greatly impacts the selection criteria for materials used. 

 

PCs and workstations are getting faster every year, following Moore's Law. With all this power and speed, the “virtual prototyping” of turbomachinery, using CFD simulations and optimization algorithms is getting more and more common. In this context, one may question if meanline design still makes sense. Let's explore the implications of this question. To do this, we have to go back to basics.

 

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Specific Speed Performance Effects

by Mark R. Anderson on Jan 18, 2019 10:35:00 AM

In my last blog, Specific Speed Demystified, I covered the mathematical definition of specific speed and how it relates to flow and work coefficient. The concept of specific speed has been a guiding principle for radial turbomachinery design for many years. Use of specific speed has been most heavily emphasized by Balje in his famous textbook and early publications.  In these works, he laid out several graphs that are still widely used today. 

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Specific Speed Demystified

by Mark R. Anderson on Jan 11, 2019 9:40:00 AM

In my blog Flow Coefficient and Work Coefficient, I outlined the basic concept behind the flow and work coefficient. These nondimensional parameters are widely used to characterize axial and radial turbomachinery. Another widely used parameter for radial design is “specific speed”. For something with such a finite name, specific speed is perhaps the most mysterious and non-intuitive parameter in all of turbomachinery. In this blog, I'll lay the ground work for understanding specific speed.

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