SpinOffs

   

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.

The Slip Factor Model for Axial, Radial, and Mixed-Flow Impellers

by Mark Anderson and Chanaka Mallikarachchi on Jul 20, 2018 10:00:25 AM

Ideally, the exit flow angle for an impeller should be the same as the exit blade metal angle. However, the exit flow angle deviates from the blade guidance at the impeller exit due to the finite number of blades. Correctly predicting flow deviation is a critical task in meanline and through-flow modeling because the exit flow angle is directly related to the work input and the pressure rise across the impeller.

Engine-Driven Compressor for Maintaining Aircraft Cabin Pressure

by Dan Hinch on Jul 11, 2018 12:27:47 PM

Commercial and military aircraft require that preset levels be maintained for aircraft cabin pressure, airflow, temperature, and humidity — regardless of flight altitude and aircraft speed. To satisfy these requirements, some amount of the airflow is typically removed from a bleed port located in a compressor section of the main engine, and the air pressure is adjusted to a preset level (through a pressure loss device) before it goes into the cabin. A better, and more effective, way to maintain the cabin environment over all of the aircraft’s operating conditions is to use a dedicated compressor driven by the main engine. Both the main-engine bleed system and the engine-driven compressor (EDC) need an environment control system to maintain cabin temperature and humidity.

What is a Consortium, and Why Would You Join One?

by Dr. David Schowalter on Mar 16, 2018 11:14:20 AM

Merriam-Webster’s definition is, “an agreement, combination, or group (as of companies) formed to undertake an enterprise beyond the resources of any one member.”  The word is Latin, derived from “con” (together) and “sors” (fate).  In commercial industries that rely on technology development, a consortium can be a way to share the cost of research and development among several companies that would benefit from the resulting technology. Consortia can also be commercial in nature.  One example would be the company, Airbus, which was originally a consortium of European aerospace manufacturers. It eventually evolved into a standalone company, Airbus, SAS. 

Compressor Design: Influence of the Impeller Exit Blade Angle

by Dimitri Deserranno on Jan 19, 2018 8:46:55 AM

During the compressor design process, one of the key optimization steps is to adjust the impeller exit blade angle with the goal of achieving the desired pressure ratio, efficiency and range.

 

When we consider the fundamental relationship of impeller work, using Euler’s turbomachinery equation for specific work (Figure 1), we can see how the impeller blade exit angle has a direct impact on the impeller work through changes in the impeller exit absolute tangential velocity, CƟ2. Based on this equation, you might think that having pure radial blades is best, since radial blades allow for more work to be performed (for a fixed impeller exit radius), leading to higher pressure ratios. Unfortunately, there is a downside….

What Next for Wider Flow Range Centrifugal Compressors?

by Dr. Colin Osborne on Sep 21, 2017 2:04:51 PM

Flow range is an essential consideration in the design of any centrifugal compressor system, regardless of the application. Adequate flow range is necessary, not only to assure that various off-design operating conditions are reachable, but that companion efficiency goals at off-design points are favorable. For many applications, these off-design points are located at the extremities of the compressor map (near choke or stall). In addition, it is not enough just to reach these off-design points; additional flow margin is needed to ensure surge control equipment can protect compressors from system surge events, including design uncertainties, manufacturing and assembly tolerances, as well as unexpected operating conditions.

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