SpinOffs

When fluids undergo a phase change (see Phase Change - Make Mine a Double), it typically has a very significant effect of the flow behavior and energy level of the system.  Some examples of this are: cavitation in a pump, condensing near the exit of a steam turbine, even the everyday phenomenon of the weather is basically a never-ending phase change process of water, and its interaction with air. 

Our CTO, Mark Anderson, takes a fundamental look at simple stall and its impact on turbochargers stability and range. This is the second video in this 2-part series. Be sure to watch Part 1 first!

Turbomachinery performance is almost always analyzed and tested with a fixed inflow condition. In other words, the assumption is that the inflow fluid temperature and pressure is defined and unchanging over the map of machine performance. Since varying conditions often exist in practice, the performance maps are sometimes normalized, as shown in the figure below. The pressure ratio of a compressor is plotted versus a corrected mass flow range and rotational speed. 

Our CTO, Mark Anderson, takes a fundamental look at simple stall and its impact on turbochargers stability and range. This is the first video in this 2-part series. 

I work with water a lot here at Concepts NREC. Water is frequently the fluid that flows through various types of rotating equipment we design to either release or store energy. Mankind’s fascination with manipulating the movement of water goes way back; read Mark Anderson’s blog on  Early Water Handling to see just how far back it goes. Today, more advanced turbomachinery is used for both hydroelectric and hydrokinetic applications. 

As discussed in my previous blog post, Flank Milling, How Hard Can it Be?, turbomachinery blades are commonly designed as ruled surfaces, with the goal of making manufacturing easier and faster with flank-milling.  While some non-ruled surfaces can be acceptably flank-milled, the programming and machining process for flank-milling is generally more dependable with ruled data. However, the ruled data should be well conditioned, and several pitfalls should be avoided during the design and construction process.

In a previous blog, Fluid Phenomena Primer: Energy Versus Temperature, Specific Heat, I 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.

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...

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.