SpinOffs

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.

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. 

When discussing the efficiency of transforming one form of energy to another, circularity is the way to go. Anyone who has spent even a little time studying engineering thermodynamics knows that the continuous transformation of energy from a heat energy source to produce mechanical or electrical power must contend with components that operate in a cycle. The key word here being “continuous”. The combustion of any carbon-hydrogen bond material (i.e., fossil fuels), or the liberation of heat energy from any number of materials when placed in a piston-cylinder, would not be very useful if the piston is not returned to its initial “precombustion” position. It is literally the difference between the one-time launching of an object from the cylinder or the continuous production of rotary shaft power; power that can be used to propel a vehicle forward or turn an electric generator. It is the cyclic operation of the fluid in the thermodynamic cycle that enables heat engines and refrigeration cycles to provide continuous power, or cooling, that is needed for the safety, security, comfort and all the other “hierarchy of needs” that was so well formulated by the renowned humanist psychologist, Dr. Abraham Maslow.

Summer is almost here, at least in my hemisphere, so here are some of the best places around the world people in the turbomachinery industry might find interesting! Know of another? Share your favorite!

Turbomachinery equipment is generally segmented based on whether it extracts energy (e.g., turbines) or adds energy (e.g., pumps and compressors). The addition of energy is usually used to compress or move a fluid. When the fluid is a gas, the turbomachinery equipment is typically referred to as a fan, blower or compressor. This blog will explore the differences between these three devices and where they are used.  

In my previous blog post, “How the Design of a Wind Turbine Differs from other Types of Turbines”, I showed that the very small pressure drop across the rotor makes wind turbine design different from other types of turbines. This blog will focus on the best method to design a wind turbine rotor based on the fact that only kinetic energy is available to extract from the wind.

The great engineer, Dr. Nikola Tesla, is best known for his work with alternating current (AC) electricity, but, did you know that he patented a bladeless type of turbomachinery in 1913? Called the Tesla Turbine, he developed it while trying to make an engine that was light enough to power his ultimate goal of building a “flying machine”. Tesla-type turbines can also be referred to as multiple-disk, friction, shear-force, or boundary layer turbomachinery.

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.