Dynamic solutions for a fluid world™

AFT President & Founder | ASME Fellow - Trey founded AFT in 1993. He was the original developer of AFT Fathom (including the GSC and XTS modules), AFT Arrow and AFT Impulse. He was active in software development until 2011 and still works with the development team in addition to managing AFT. He has taught hundreds of training classes on AFT’s ...software products in twelve countries across every populated continent. He worked previously for General Dynamics in cryogenic rocket design and Babcock & Wilcox in steam/water equipment design. He holds a BSME (1985) and MSME (1986), both from the University of California, Santa Barbara. He is a registered Professional Engineer.   More
Trey Walters

What is Pogo and Why On Earth Would Anyone Want To Suppress It?

The time was almost 30 years ago and it is fair to say I was not quite out of the "still wet behind the ears" stage for an engineer. I had been working in industry for about three years and I was just given a project that would change my career direction and, in fact, my life. The project? I was assigned to evaluate a new concept Pogo suppressor on a cryogenic rocket engine liquid oxygen (LOX) feedline. 

How did I end up getting assigned this project? Well, I had a few things going for me at that stage of my career. Firstly was that my company division was on a massive hiring spree. Since I had been hired three years earlier my division had doubled in size. Fortuitously for me, that meant I was now in the upper 50% of seniority. Secondly, I had just had a performance review and I had casually told my immediate supervisor during the review that I would be interested in learning about waterhammer should the opportunity arise. Thirdly and finally, I had demonstrated a knack for solving tough analytical problems. What that meant is that I was in the enviable position of having my supervisors assign me to any problem that was out-of-the-ordinary and otherwise unusually difficult. The new Pogo suppressor was such a problem.

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Trey Walters

Star Wars vs. Star Trek: Which Is Better?

Last week I saw Star Wars: The Last Jedi. For the third time. If you have not seen it by now you probably do not care about it much, but nevertheless rest assured there are no spoilers here for The Last Jedi. I first saw it on opening day in December. Usually I would only see a Star Wars movie twice in theaters. But a circumstance came up with one of my sons and I ended up seeing it a third time. I am definitely a fan of Star Wars.

The original Star Trek was on television when I was in kindergarten. I was definitely a fan of the original series but I never had time to keep up with the following television series. I have seen all the Star Trek movies going back almost 40 years now.

So which is better?

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Trey Walters

Shhhh! Suppressing Sound Waves From Rocket and Space Shuttle Engines

In case you have not noticed, rockets can be really loud. Sound suppression on vertically launched rockets (and the Space Shuttle, back when it was flying) is more important than most of you would think. And for a different reason than most of you would guess.

Every so often I get to talk about my first job which was in the aerospace industry where I first learned about sound suppression systems. Today AFT software is used on several of these systems by our customers in the aerospace industry as well as NASA. 

The flowrate of water used in the sound suppression process is enormous. Which is why they are often called "deluge systems".

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Trey Walters

The Knowledge Quest: Connecting With Fluids Education at Universities

This week was not a typical week for me. For the first time in 30 years I found myself in not one, not two, but three university classrooms. Each classroom was in one of Colorado's excellent engineering schools.

I had a chance to come face-to-face with about 140 students in classrooms this week and several professors. A number of positive things came of the week which I will summarize below.

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Trey Walters

Hydropower Big and Small: My Recent Visit to a 5 MW Plant

Pikes Peak in Colorado, USA is often called "America's Mountain" and is the most visited mountain in North America and second most visited in the world. Barr Trail is the 13 mile (20 km) hiking trail that leads from Manitou Springs to the top of Pikes Peak. And right next to the Barr Trail trailhead is the famous 100+ year-old Manitou Hydro Plant.

Famous? Why is this tiny 5.5 MW hydroelectric power plant famous?

And how would a fluid systems engineer like myself compare it to other famous dams like the 14,000 MW Itaipu Dam and the 2,000 MW Hoover Dam?

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Trey Walters

Hurricanes and the Art of Computer Modeling

Hurricane Irma ravaged the Caribbean Islands and the state of Florida. Sixteen days prior, Hurricane Harvey ravaged the coastal area of Texas. Weather experts said this was the first time in recorded history that two Category 4 hurricanes made landfall in the United States in the same season. Each hurricane caused billions of dollars in damage and impacted millions of people.

Especially in Irma’s case, there was considerable discussion of the computer modeling used to predict the path and strength of the hurricane. As I have worked in computer modeling for most of my 30+ year career, this piqued my interest and I decided to educate myself a little more on the topic as it relates to hurricanes.

The first resource I pursued is one of our software developers here at AFT, John Lindsay. John has an undergraduate degree in Meteorology and a Master’s degree in Computer Science. John is a self-described weather geek who has a weather station at his home. We talked about weather modeling and he gave me some links to read further, which I did.

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Trey Walters

The Itaipu Dam vs. the Hoover Dam is No Contest: Itaipu Wins By a Landslide

Unknown to me, a few weeks ago I was sitting across from a Brazilian hydroelectric engineer on an airplane flying across Brazil. His name was Roberto and he did not speak English. I myself was learning the basic Portuguese phrases but that was the extent of my language skills. I was traveling with my son (an engineering student himself) who was spending the southern winter (i.e., northern summer) working in São Paulo, Brazil. My son had learned to speak Portuguese amazingly well and struck up a conversation with Roberto. That was when he found out Roberto was a civil engineer who used to work in hydroelectric power.

I have to confess that until that day a few weeks ago I had never heard of the Itaipu Dam - the largest hydroelectric facility in the Americas and, until a few years ago, the largest in the world. Roberto and his family were planning to tour the dam as part of their trip to the area where the borders of Brazil, Paraguay and Argentina meet. When we landed my son and I hatched the idea to rent a car and see if we could get in on a dam tour ourselves.

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