PSU, we have liftoff

Close to 200 miles above the earth, astronauts are experimenting with an idea that a Portland State professor developed over three years ago.

It’s an idea that Mark Weislogel, a professor of mechanical engineering at PSU who is leading the research project for NASA, says could change space travel for the better by improving the efficiency of fluid flow, such as water or fuel, on space shuttles and space stations.

“We really think we’ve got something,” Weislogel said.

Because the gravity in space is close to zero, fluid often breaks apart, causing it to float like bubbles in the air or stick to walls of the tubes it travels through, preventing it from efficiently flowing through pipes.

The experiments that astronauts working with Weislogel are performing study the capillary flow of fluid through six different units that Weislogel designed. The units are divided into three groups, each with at least one tube and various other devices to study the flow of liquid.

The experiments will test which of the unit designs use capillary forces most efficiently to cause liquid to pass through them, according to “How to Manage Floating Fluids in Space,” an article published by NASA about the experiments. All of the experiments are being performed on the International Space Station, a 500,000 pound research station that has been in construction just above the earth for close to 10 years.

The tubes are designed to resemble various systems used on a space shuttle or a space station–anything from a ship’s fuel pump to its waste removal system.

Better fluid flow will help machinery operate more efficiently, Weislogel said. The small differences in the pairs of tubes can drastically alter the flow of the fluid traveling through the tubes, which are made out of Plexiglas.

One group, called the Capillary Flow Experiment Contact Line, is made up of four tubes. The two outside tubes are built like pistons on an engine and use applied pressure to push fluid into the inside tubes.

Once liquid is in the tube, the astronauts disturb the liquid by flicking or tapping the container. Weislogel and his researchers then observe and analyze how the liquid responds.

Capillary forces can be seen everywhere. Blood that passes through our veins is pumped out by our hearts, and then pulled to our fingertips and toes by capillary forces through our tiniest blood vessels. Capillary forces are more efficient in a smaller space. When blood flows through a wide vein, it moves slowly, but in a narrow vein, the blood moves quickly.

As is true with blood flow, the efficiency of liquid flow in space is dependent on the size, shape and construction of the tubes.

Gravity prevents capillary forces from moving fluids very far on Earth, according to the NASA article. But because of the lack of gravity in space, the article reports that capillary forces will push the fluid through systems in space shuttles, such as fuel lines, much more efficiently.

This is a power that NASA is trying to harness, Weislogel said. Astronauts are now, and have been for three years, videotaping experiments using the tubes that Weislogel designed.

Weislogel–with his team of five PSU students, and other researchers at Purdue University and the NASA Glenn Research Center–continues to use the videotapes that the astronauts have recorded to observe and record data about which design provides the most efficient motion.

With the data he gathers, Weislogel said he hopes to be able to help designers who build systems such as fuel lines or air-cooling systems used on space shuttles and space stations. With this data, he said, designers will be able to know which designs will work and which will not.

“Without getting absolutely nerdy,” Weislogel said, “if the shape of one of the tubes is changed slightly, it will drastically affect the efficiency of the fluid’s motion.”

The research has been an exciting experience for Ryan Jensen, a graduate student in the mechanical engineering master’s program who is working with Weislogel on the project. Jensen spends most of his days watching the videotape that the astronauts have recorded, analyzing and noting any differences he sees in fluid motion among the different tubes.

“I’m contributing to real science,” Jensen, 21, said. “The travel and the exposure-it’s pretty amazing.” Jensen has been able to spend time training astronauts with tips on how to perform the experiments in cities as far away as Houston and Cleveland.

The research team is currently only able to watch videos the astronauts have recorded through a live feed that the team downloads from the internet. Because the quality of the feed is so low, Jensen said that he can’t wait to see high-resolution recorded videotape.

High-resolution videos are sent to Weislogel and his research team when a space expedition group returns home. The team is still waiting for tapes from Expedition 14, the space shuttle that returned from its mission in April.

Despite only having mostly low quality video, Weislogel said the research team is filled to the brim with information and data to compile and study.

“We have so much data, we’re in trouble,” Weislogel said.

Weislogel plans to spend the next year to 18 months analyzing data, which he plans to publish in scientific journals periodically. NASA is funding his research for the project with “hundreds of thousands of dollars” in grants, though Weislogel was unsure of a specific number. He said they recently added $85,000 so that he could continue his research.