Research - Mark Weislogel

The low-g, or microgravity, environment of space provides particular challenges to the designers of fluid/thermal systems for spacecraft. The unique problems arise primarily as a result of the limited opportunity and high cost of access to space and thus the subsequent inability to rely on trial and error techniques for even the most mundane operations. For example, imagine the process of preparing a cold glass of chocolate milk from powder in a spacecraft. So simple on the ground but in space? Contain the powder, contain the liquid, mix the two? Not so fast. Even to experts in the field, such a process would require a fairly clever solution based on physics, predicted by analysis, and verified by terrestrial experiments (i.e.1-g, drop tower, aircraft, etc). Even then, would the solution be compact, lightweight, affordable, and, of course, failsafe? The engineers at NASA, and throughout the aerospace and engineering community routinely face such challenges for much more complicated and essential systems. What fun places to work!

I thoroughly enjoy thinking about low-g fluid phenomena and my hopes are to contribute to the field in any ways that increase design options and flexibility, simplify components and processes, decrease design time, reduce design and hardware costs, and most importantly increase system reliability. The above is possible through the study of fundamental low-g fluid phenomena. My special interest is in analytical and experimental research of capillary dominated flows. Experiments in this field are exciting and require the use of NASA drop towers and low-g aircraft. In certain cases experiments aboard the space shuttle or space station(s) are required.

I have enjoyed collaborations with other researchers in this field, most notably: P. Concus (U.C. Berkeley), R. Finn (Stanford U.), S. Lichter (Northwestern U.), D. Langbein (ZARM, Germany), M. Dreyer (ZARM), L. Trefethen (Tufts U.), R. Balasubramaniam (NASA GRC, NCMR), J. McQuillen (NASA GRC), S.H. Collicott (Purdue U.), H. Ross (NASA GRC)

just a minute...still waiting?

surface image

There are many challenges remaining for the designers of thermal systems for spacecraft as well as the terrestrial environment. These include the challenges of cheaper more reliable more compact systems that require less power, and transfer more heat over greater distances and at higher heat fluxes. Systems developed for application in space also require the potential for thorough ground-testability. A very 'cool' field is that of passive and semi-passive systems which circulate a working fluid carrying heat from source to sink without the use of a mechanical pump. A variety of heat pipes have been developed and analyzed to this effect and include high performance devices such as Capillary Pumped Loops (CPLs) and Loop Heat Pipes (LHPs). Each system has unique advantages and limitations.

An under-developed class of oscillatory thermal cycles, though receiving little attention to date, targets a unique regime between traditional heat pipes and mechanically pumped loops. The oscillatory thermal cycles can generate large driving pressures on par or exceeding those of practical mechanically pumped loops, but the systems are passive like heat pipes. Thus, the passive cycles have the potential to be cheaper (no mechanical pump) and more reliable (few moving parts) than mechanically pumped systems while able to transfer more heat over greater distances and at higher heat fluxes than capillary pressure driven heat pipes.

The emerging field of oscillatory cycles was recently and briefly reviewed (STAIF Conference 2002). The research effort of my group at PSU focuses on fundamental analytic and experimental investigations of a novel cycle originally conceived at NASA Glenn Research Center (ref patent). The advantages of the cycle appear to persist at micro- and macro scales and efforts are in process to demonstrate cycle operation in these limits. Application to thermal control in spacecraft as well as to residential and commercial terrestrial applications (i.e. high power/flux electronics) are obvious and being eagerly pursued.

Again, concerning this work I have enjoyed and benifitted from collaborations with J.D. Wright, B. Hitch, K. Libberton, and B. Windecker (TDA Research Inc.), and J. McQuillen and E. Golliher (NASA GRC).

Micheal Bacich: Pulse Thermal Loop (M.S.M.E. 2004-05)

Cory Nardin: Capillary Driven Flow (M.S.M.E. 20004-05)

Yongkang Chen: Capillary Driven Flow (Ph.D. Post-Doctoral Fellow 2004-05)

Justin Davidson: Pulse Thermal Loop (B.S.M.E. 2003)

Aaron Frechette: Capillary Driven Flow (B.S.M.E. 2003), De Gaul, or PSUman

Megan Sala: Pulse Thermal Loop (B.S.M.E. 2003)

NASA Undergraduate Student Microgravity Projects

Undergraduate High Altitude Balloon Projects

Highschool Summer Student Projects

Water Balloons in Microgravity

Highspeed Rupture of Water Balloons in 1-g

Angular Liquid Bridge Experiment on Shuttle

Interface Configuration Experiment on Russian Mir Space Station (some rot)

Interface Configuration Experiment on Space Shuttle (some rot)

Two-Phase Flow in Microgravity

National Space Grant Student Satellite Program

NASA Live Broadcasts

Offspring visits PSU Alumni Center (jpg)

Geek Wannabe (htm)

Stunt Double courtesy J. McQuillen (jpg)

'Expert Panelist' Bloopers (jpg)

Two-Phase

What a gas, LPSU Balloon Launch 2004 (10.8Mb mpg)

CFE ISS Astronaut Mike Fincke, Axial Mode Drop Ejection (3.1Mb mpg file)

CFE ISS Astronaut Mike Fincke, Centrifuge Method (14Mb mpg file)