SpinOffs

   

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. 

The Ultimate Fluid Model: Non-Equilibrium Modeling

by Mark R. Anderson on May 24, 2019 10:42:37 AM

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.

Getting Real – Advanced Real Gas Models

by Mark R. Anderson on May 3, 2019 10:28:59 AM

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. 

Going Through a Phase – Modeling Phase Change with Cubics

by Mark R. Anderson on Apr 26, 2019 9:32:08 AM

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. 

The Challenges & Cures of CFD Solution Failures

by Mark R. Anderson on Aug 3, 2018 10:04:04 AM

Computational fluid dynamic analysis (CFD) has become a standard part of the turbomachinery design process. Within Concepts NREC’s Agile Engineering Design System, FINE/Turbo, from our Partner NUMECA International, is the tool used to accomplish aerodynamic analysis of designs by applying standard methods of three-dimensional analysis. However, arriving at a converged CFD solution in any CFD program can sometimes be a challenge.

Avoiding the "Bad Day" in Aerospace

by Francis A. Di Bella, P.E. on Jul 6, 2018 9:17:04 AM

The AS9100 Certification identifies companies who have qualified to manufacture products for the Aerospace Industry.  Manufacturers who meet the extensive requirements of the AS9100 Certification have committed to maintaining quality assurances that ensure that their products are engineered, manufactured and maintained to provide the aerospace customer with a quality product. 

An Initial Look at Conical Diffusers in Turbomachinery Design

by Jamin Bitter on Jun 22, 2018 12:01:00 AM

Perhaps the most common type of diffuser in turbomachinery is the conical diffuser. This diffuser is found at the exit of every volute as the geometry transitions to the exit flange. This conical diffuser must be sized appropriately to maximize machine performance across the desired flow range and can have a large impact on the end footprint and performance of the turbomachine.

Is Laboratory Testing Still Needed for Turbomachinery Development?

by Andrew Provo on May 17, 2018 1:31:41 PM

Historically, testing has played a critical role in the turbomachinery design process and multiple rounds of “design, test, analyze, repeat” were not uncommon.  Today however, the industry seems to be drifting away from development testing. Often, the only scheduled test in a development program is the performance validation test of the first assembled system. I believe this trend exists for three main reasons:

Great Designs Deserve to Shine

by George C. Zitka, P.E. on May 4, 2018 9:18:40 AM

If you are a turbomachinery engineer, you know you can spend days, weeks, or even months analyzing various design iterations, looking for the optimal choice for the application.  When you go to present your final design for review, you want it to look as good as you know it is. Choosing the best post-processor for CFD results can not only save time in creating the desired views, but also show solutions at their best.  Without proper post-processing, your solution can lose that "je ne sais quoi" that made it the best design for the application. In other words - it has to look as good as you know it is.

The Best CFD Averaging Methods for Distortion

by Mark R. Anderson on Aug 9, 2017 3:24:38 PM

Three-dimensional flow fields typically have some degree of distortion in the flow properties and flow profiles across a given cross section. These distortions can be quite significant in regions that include the exit plane of the impeller. Because most designers are interested in averaged values of performance, the question often arises as to what averaging technique is the best to use.

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