SpinOffs

   

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

by Xuwen Qiu, Chanaka Mallikarachchi, and Mark Anderson 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.

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. 

What Is Pogo and Why Is It Bad For Rockets?

by Kerry Oliphant on Jun 28, 2018 5:21:25 PM

Space launch vehicles can exhibit self-excited longitudinal oscillations, also known as “Pogo” — so named because the phenomenon vibrates the rocket up and down in a manner similar to bouncing on a pogo stick. The vibrations severely impair the astronauts’ ability to pilot or respond to emergencies and can cause structural failure of the vehicle. NASA first became aware of the disastrous consequences from Pogo during the Gemini-Titan program. The issue continued to plague the agency through the Saturn V Moon launch missions.

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.

A Small Taste of Two Papers from Turbo Expo 2018 in Norway

by Barbara Shea on Jun 14, 2018 11:15:18 AM

The 2018 ASME Turbo Expo in Lillestrøm, Norway was, as always,  a smorgasbord of papers and presentations on the latest and greatest ideas in turbomachinery and gas turbines. Two of our favorites were from Mark R. Anderson and Felipe F. Favaretto, Concepts NREC employees. Coincidence? I think not. Felipe presented, “Development of a Meanline Model for Preliminary Design of Recirculating Casing Treatment In Turbocharger Compressors”:

Online Versus In Person Training: The Pros and Cons

by Barbara Shea on Jun 8, 2018 12:01:00 AM

Ongoing education is a reality for most professionals. The training requirements are usually set by employers or professional associations with the goal of keeping employees and members up to date with the latest technologies, theories, and/or tools available in the industry. Numerous disciplines require Continuing Education Units (CEUs) to maintain certifications, including engineers, educators, nurses, and many others. Increasingly, employers are specifying a professional development goal as part of their employee’s yearly review. Those reviews impact your continued employment, your salary and your career path.

Lessons Learnt

by Kevin Fairman on May 31, 2018 11:42:37 AM

Yes, you read that right. Learnt. It’s in the dictionary; look it up if you don’t believe me. I believe it’s one of those words that came over on the Mayflower and found its way into Webster’s early version of spell-check. I was exposed to this word through a group of Englishmen in the Engineering group here. One of those Englishmen, Colin Osborne, has been a significant contributor to our robust “Lessons Learnt” database throughout his decades-long career here at Concepts NREC. If you don’t have a “Lessons Learnt” database at your company, I suggest you start one right away.

Film Cooling In Turbines

by Song Xue on May 24, 2018 4:43:24 PM

Turbine inlet temperature is one of the most critical parameters in the Brayton cycle of gas turbine engines. One way to increase the cycle efficiency is to increase the turbine inlet temperature, as illustrated in Figure 1. Here, a typical Brayton cycle T-S diagram chart visualizes the impact of higher turbine inlet temperatures on higher efficiency. Indeed, the area between the solid curves through points 0-3-4-8 represents the useful power generated by the turbine. The cycle efficiency can be calculated by dividing this area by the total area below curve 3-4, being the heat input. The dash lines convey the cycle with increased turbine inlet temperature, and the new cycle efficiency is the area in 0-3’-4’-8 curves divided by the area below curve 3’-4’. It is easy to see how a higher turbine inlet temperature increases cycle efficiency. Because of pursuing higher efficiency in modern gas turbine engine design, turbine inlet temperature has been pushed to a level that most material cannot withstand without effective cooling. Figure 2 shows the increasing trend of turbine inlet temperature since the 1940’s. Since the 1970’s, the turbine inlet temperature has been above material capability through the introduction of turbine cooling techniques.

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:

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