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FORGIVE MARK WEISLOGEL if he looks a little tired. He's about to leave for Japan, and he just got back from India. "I spent 30 hours in transit to get there," he says, "First I flew to London, then Bombay, Bangalore, and Hyderabad. I couldn't sleep on the planes, so I was up for 50 straight hours."
Weislogel, a professor in the thermal and fluid sciences group at Portland State's Maseeh College of Engineering and Computer Science, finds himself a sought-after presenter in the field of fluid dynamics, thanks to his work with NASA on the International Space Station. Designed to illustrate fluid movement processes under zero- or micro-gravity conditions, Weislogel's experiments offer the promise of better fluid movement and delivery systems in the future—ranging from bubble-free IV systems for hospitals, to "lab on chip" modules used to process biological samples, to more efficient hydrogen fuel cells, to improved ink cartridges for computer printers and copiers.
"It's pretty exciting," Weislogel says. "NASA wants us to tell the story." Hence Weislogel's upcoming presentation at the International Symposium on the Physical Sciences in Japan, with presentations to follow in China, Australia, Canada, and the United States.
Weislogel's specialty may be obscure, but the basic concept is simple. On Earth, fluid management systems like water mains and automobile fuel tanks work with gravity to move their contents around. Weislogel and his co-investigators, including Purdue University's Steven Collicott, are investigating how the shape and dimension of their containers can help move liquids when gravity doesn't apply. While the immediate applications of this technology are improved water and fuel systems for spacecraft, there is also an extensive array of potential applications here on Earth.
"The better we understand how capillary flow works in space, the better we can make these systems work on the ground," Weislogel says. "The possibilities are limitless for things like biological scaffolds"—peptide-based, laboratory-grown support systems that can help spinal cord injury patients regenerate nerve tissue, "high-efficiency fuel cells that rely on capillary flow, and things like better laptop cooling systems, which are driven by wicking."
BY DAY, WEISLOGEL can be found in a PSU classroom, teaching courses in Applied Fluid Mechanics and Thermodynamics as well as Capillary Flows and Phenomena. In his "spare" time, he and his grad students are immersed in grant-funded research for NASA, the National Science Foundation, and private corporations. Most of the experiments they design are focused on unlocking the mysteries of capillary flow, including what happens when the surface of a liquid comes into contact with a solid. "Wicking"—the phenomenon that occurs when you dip the corner of a paper towel in water—is one example of capillary flow.
On Earth, gravity tends to overwhelm and dampen capillary force. But in space, in the near-absence of gravity, capillary forces express themselves freely. Introduce a rotating vane to a specially designed vessel, for example, and the agitated liquid—silicone oil, in the case of Weislogel's NASA experiments—reacts far differently than it does on Earth. Careful review of the ultra-slow-motion videos of the zero-g NASA experiments reveals nuances of liquid behavior that exponentially multiply the data Weislogel and his colleagues would obtain from a similar, earthbound experiment.
NASA is interested in Weislogel's research because of the unique engineering challenges inherent in a zero-g environment. Instead of hugging the bottom of the tank as it does on Earth, liquid rocket fuel, for example, becomes a free-floating blob of liquid, reacting to the motion of the shuttle vehicle. The less fuel is in the tank, the more room the "blob" has to move around, and the more acute the problem becomes.
"Aboard the shuttle, you don't want to have liquid shifting unpredictably from one side of a container to the other," Weislogel says. "It may sound like a small thing, but when you're talking about 80,000 pounds of rocket fuel, that's a pretty significant weight shift. If you didn't predict it, that would be very bad; it would shift the entire center of gravity on the ship."
By changing the geometry of the containers used to carry liquids on board the shuttle—say, from a cylinder to an ellipse—and introducing simple elements like internal vanes to shift the liquid from one part of the container to another, Weislogel and colleagues are helping NASA solve such vexing problems. "Most of the older systems rotated to produce artificial gravity," he explains. "That adds risk, mass, and power draw. The solutions we're designing are more passive and elegant. They may or may not perform as well, but then again, they may not need to."
BECAUSE NASA IS PLEASED with the information generated by Weislogel's 19 capillary flow experiments aboard the International Space Station, it has asked him to help design the futuristic fluid delivery systems aboard its next-generation Crew Exploration Vehicle (CEV). The CEV, currently scheduled for deployment in 2014, will be capable of carrying a crew of four into lunar orbit.
It's an exciting prospect. But for now, Weislogel is keeping his feet firmly on the ground. After a career that included 10 years at NASA and a stint at a private aerospace firm in Colorado, he chose Portland State.
"I wanted to come to PSU because it was the most interesting place in the Northwest that I looked at," Weislogel says. "I felt PSU was on the rise, and I wanted to be a part of that. I love the whole student-teacher thing. I love helping my students along their path and firing them up about science. They're really good—they can do anything. I really like them—don't tell them that, but I do."