Here on the surface of the planet, when we pull the plug on a sink, we know exactly what to expect: water will rush in a vortex down the drain. Whether in a sink basin, a fuel line, a pipe, even a river, fluids behave reliably in the grip of earth’s gravity. But head up about 220 miles to where the International Space Station (ISS) is circling in a low orbit and you’ll find the rules have changed.
In a ‘free fall’ low-gravity environment, such as that aboard an orbiting spacecraft, fluids behave in strange ways. Sure, that makes for fun videos of astronauts gulping at globular masses of stellar brew as they float weightlessly around the ISS, but from the point of view of the NASA engineers designing life-supporting systems essential to operational feasibility and safety, the strange behavior of fluids present a series of challenges. How do you get fluids to go where you want them to without gravity? How do you separate gas from liquid without the denser of the two naturally sinking? Here at PSU, innovators and long-time collaborators, Dr. Mark Weislogel, Professor, Dept. of Mechanical & Materials Engineering, and Ryan Jenson are designing, manufacturing, and testing devices to manage unruly fluids and gases in low gravity, and they believe they’ve got something that could lead to a revolution in spacecraft fluid systems designs.
Last year, IRPI, an R&D and consulting firm co-founded by Jenson and Weislogel, was awarded a Small Business Innovation and Research (SBIR) grant from NASA for the first phase of a project that aimed to address challenges faced by engineers building fluid systems for spacecraft. They proposed a review of the current technologies and a radical rethinking of how such systems were engineered. Using novel geometric properties they were able to design a device capable of separating liquid and gas. Their In-line Passive Fluid Phase Separator does not require power, has no moving parts, and can greatly improve the performance and reliability of a number of fluids systems. Weislogel and Jenson were able to manufacture their device using 3D printing technology and demonstrate how the technology would work in the simulated low gravity environment of the Dryden Drop Tower in the Engineering Building at PSU.
“The idea,” Jenson said, “was to create a system and components actually suited for operation in low gravity, which hadn’t been done before. So what we did was design capillarity into the system and we ended up with a device that could increase the reliability and performance of all kinds of systems.”
According to Weislogel and Jenson, the device could be added to most fluid transmitting systems aboard the ISS. The separator, which looks like a rectangular block of plastic with lines on either side and a series of chambers built into the block, could be installed into any system simply by ‘cutting it in’. Compared to other methods of separating phases in capillary flow streams, such as using a spinning centrifugal separator to force liquids and gasses to opposing ends of a cylinder on a centrifuge, the device is simple, inexpensive, easy to install, and efficient. With such a system, astronauts will need to make fewer repairs to faulty and failing equipment. This could allow scientists and astronauts even more time to focus on their experiments that add to our knowledge and improve lives back down here on earth.
In support of the project, Innovation & Intellectual Property recently filed a provisional patent application on Jenson’s and Weislogel’s designs for the In-line Passive Fluid Phase Separator. In the near future, this NASA-funded, PSU-developed device could be working in the dark, improving the function and reliability of critical life-support systems aboard the ISS or other craft operating in a low gravity environment.
“Eventually, we’d like to have a number of these components,” Jenson said. “And the agencies building spacecraft will be able to tell us what they need and we’ll be able to build it, test it, certify it, and have it to them in a matter of days, if not weeks.”
The International Space Station is one of the largest, most complex, and expensive machines ever built. But like anything, its success depends on that of its constituent parts. Designed with capillarity in low gravity environments in mind, the In-Line Passive Fluid Phase Separator was built with the intent of improving the performance and reliability of some of the key systems that protect our astronauts and keep them alive.