From Detonation to Diapers at Los Alamos National Laboratory
When you think of Los Alamos National Laboratory (LANL) what comes to mind? Perhaps the first atomic test on July 16, 1945? Or scientists today busily tending the US stockpile of nuclear weapons deterrent? Maybe in your mind's eye you can envision a sprawling, complex of buildings located in the stark beauty of the northern New Mexico desert where highly-classified government programs are conducted.
You probably don't think of diapers. But you should.
There is a direct correlation between the advanced computational tools developed over the years to help ensure the reliability of the nation's nuclear weapons and high tech diapers invented by Procter & Gamble to keep kiddies dry and comfortable.
LANL and P&G have been working together for almost 20 years to turn the codes developed for national security into tools for advanced manufacturing. One of those projects involves using LANL's library of computational fluid dynamics (CFD) codes in the service of designing a better diaper manufacturing process.
Of course, the software can be used to address a wide variety of CFD problems in addition to perfecting Pampers. Los Alamos is offering the codes free of charge to US industry as part of President Obama's Advanced Manufacturing Partnership and the newly-created National Digital Engineering Manufacturing Consortium (NDEMC).
A Long History
The scientists and engineers at LANL have been interested in the study of how fluids move and are propelled since the Lab's inception in 1943. For example, until the nuclear test ban treaty was signed in 1963, the lab studied how liquefied rock and metal melted by underground blasts moved through the test site environment.
"They realized that fluid dynamics could be used for a broad spectrum of applications, including many manufacturing processes," says Antonio Redondo, Division Leader of the Theoretical Division at LANL.
By 1980, according to Redondo, the division had accumulated numerous CFD applications and more were being added all the time. It made sense to collect the code into a single package that contained common data and algorithms that could be used by many of the modules. Also, a mechanism was established to allow researchers to add their advancements to what came to be called the Los Alamos Computational Fluid Dynamics Library (CFDLib). The package, which contains both traditional and cutting-edge codes, continues to be updated.
Comments Redondo, "In CFDLib you can find state-of-the-art codes that are not yet available in the commercial fluid dynamics software you buy in the marketplace. Whenever someone writes a CFD paper in the technical literature that presents either a new model, a new way to solve the equations, or an advanced numerical development, we add it to the library well before it appears in the commercial code. The commercial packages have really nice GUIs for their users, but they don't incorporate the latest science just published in the literature."
Not for Novices
This software is not for the faint of heart.
The July 27 LANL press release announcing the availability of the codes to manufactures states unequivocally, "Use of the CFD library will require a significant level of knowledge in computational fluid dynamics. The code is intended for end-user problem solving and is not licensed for resale and redistribution. It comes with no user support by Los Alamos: however there is a broad-based user and applications knowledge community that can be tapped, and Procter and [sic] Gamble offers at no cost a front-end script to ease integration into innovation work practices. Los Alamos' Technology Transfer Office is working on a mechanism to release the CFDLib as well as P&G's proprietary wrapper that allows industry users to more simply set software parameters."
Redondo says that most of the people who contact LANL directly to ask for the code are researchers from other labs and universities located around the world.
Although some technical expertise is necessary, making use of modules from the library is not quite as daunting as the announcement makes it out to be. Also, its use is not limited to academia, the large labs and major corporations. "If a small- to medium-sized manufacturer has someone on staff who knows fluid dynamics, CFDLib could be very useful," Redondo comments. "You don't have to have a PhD in CFD to run this code. If you have someone with a degree in engineering — preferably chemical engineering — who has taken a course in fluid dynamics in grad school, they can certainly use this program."
"You have to be familiar with the discipline's equations," he continues. "For example, if you're looking at how to make water flow through a pipe, you realize there are two ways to make this happen: You can create a pressure differential at either end of the pipe, or you can apply a force to the water — for example, place the pipe in a vertical position and let gravity do the work. People using CFD codes have to understand the forces involved — for example, pressure gradients — and be skilled at using partial differential equations, such as Navier-Stokes, that model the dynamics of the fluid."
He says very few physics departments teach CFD as part of their graduate curriculum. Instead, most of the people who study fluid dynamics are chemical engineers who learn how to work with the discipline's equations as college seniors or early in graduate school.
In fact, if you are a small- or medium-sized manufacturer and you don't have a CFD-savvy technician on your staff, graduate schools provide an excellent resource to solve your problems. For example, if you need to determine what is likely to happen when you move molten plastic through a pipe or send a jet of a fluid through a gaseous medium, you can hire a graduate student (usually through his or her professor) to run the CFD code on the departmental workstations or HPC cluster.
There are other alternatives. For example, the U.S. Department of Energy sponsors the INCITE (Innovative and Novel Computational Impact on Theory and Experiment) program which makes available the supercomputing resources at Oak Ridge and Argonne National Laboratories. Researchers from qualifying institutions — including SMMs — use the supercomputer time to run complex simulations in such areas as alternative energy, climate change, biology, and materials science.
Let the Lab Help
LANL itself is a potential resource. "We're not a job shop," Redondo says, "but if a small manufacturer comes to us with a project that produces research that we can use for other things, we are definitely interested."
Typical examples of joint LANL/industry projects include:
- Interaction of the turbulence of a fluid with solid material in the casting of metals — e.g., in the design of a boat propeller or helicopter blades.
- Modeling the flows involved with making foams in a chemical reactor. This involves simulating a viscous fluid — the polymer used to make the product — and its interaction with the gases used to create the bubbles within the foam.
- Modeling of internal combustion engines including working with fluids whose density or viscosity change during the combustion process.
- Investigating what happens to materials during phase changes such as melting, freezing, or the formation of condensation.
CFDLib comes with a wrapper — a front-end script — that makes all the modules in the library available through a single interface. Also, because the library is written with a common data format, users can quickly call up a number of modules for their application, or utilize a number of different numerical techniques to solve their CFD problem. For example, both Eularian and Lagrangian particle tracking approaches are available, allowing the user to decide on whether the best solution to the problem is to treat the fluid/gas and its particles as a continuum, or treat the particulate matter as a single particle in order to track its trajectories.
"CFDLib is continuing to evolve," Redondo says. "Whether its designing a better diaper or calculating the effect of turbulence on an advanced aircraft wing, access to the latest fluid dynamics codes in our library can help manufacturers solve tough modeling, simulation and analysis problems. This can also put them out in front of their competitors who are not leveraging this leading edge software."