SpinOffs

In this blog series, I covered a lot of thermo-fluid options in engineering analysis, from the simplest perfect gas (When Perfect is Good Enough – Perfect Gas Models) and ideal liquid, (Fluid Modeling: Liquified ) to much more complex approaches (Going Through a Phase – Modeling Phase Change with Cubics) and (Getting Real – Advanced Real Gas Models). In this blog, I’ll cover the ultimate in thermo-fluid modeling: non-equilibrium modeling. It's rare and expensive, sort of like the Schorschbrau’s Schorschbock 57, a beer that sells for $275/bottle.

The Refprop program

The calculations in the National Institute of Standards and Technology (NIST) Refprop program are generally considered the most accurate thermo-fluid models available.  The routines are widely used in many applications. 

The models

Several different models are embedded in the Refprop formulation. The most important are the  Benedict-Webb-Rubin equations of state for the pressure-temperature-density relationship. 

Credit for the first gas turbine engine used in flight is given to Dr. Frank Whittle.  Dr. Whittle maintained a steadfast commitment to developing gas turbine-powered aircraft in the midst of World War II when England was being attacked by Germany’s conventional aircraft bombers. While the gas turbine aircraft wasn’t developed early enough to impact WW ll, the interest in increasing the speed of aircraft continued to spur development for use in commercial as well as military planes. The advancements in gas turbines, combined with rapid advances in several technologies, including rocketry, computers and material sciences, contributed to the dawn of the Space Age.

In the mid 1980’s, while serving in the Canadian Air Force, I had the good fortune, on one of my many adventures, to fly into Sondrestrom Air Base in Greenland. The Base is at the head of a beautiful fjord, so the scenery during the flight to Sondrestrom was magnificent. We arrived in the early summer on a beautiful clear day. I got out of the plane and wandered around the base while the aircraft was being serviced. One feature that caught my eye was all of the bright yellow ropes and stanchions that were strung from building to building. I couldn’t figure out what they were for, so I stopped one of the locals and asked, “Why the Yellow Ropes?”  Now, for those who are not students of the geography of Greenland, Sondrestrom is north of the Arctic Circle, and, apparently, the weather is not always as bright and clear as it was that day! As a matter of fact, one of the meteorological phenomena in the area was virtually instantaneous whiteouts, caused by snowstorms funneling up the fjord. Several people had been caught out between buildings and become disoriented during a blinding storm, a dangerous thing during the long darkness of winter. To eliminate this danger, they had put up the yellow ropes to safely guide people to their destination.