Miscible Fluids in Microgravity (MFMG)
Research Area: Fluid Physics
Expedition(s): 8-11 and 29-ongoing
Principal Investigator(s): ● John A. Pojman, PhD, Louisiana State University, Baton Rouge,
Louisiana
RESEARCH OBJECTIVES
Honey and water are miscible fluids, that it, fluids that dissolve completely in each other.
Miscible Fluids in Microgravity (MFMG) involves having water injected into honey to test if it
will act like an immiscible fluid, such as water being injected into oil, and spontaneously form a
spherical drop. The experiment needs to be performed in weightlessness.
EARTH BENEFITS
The experiment may have relevance to
microfluidics.
SPACE BENEFITS
If we show that convection can be caused
by an effective interfacial tension
between miscible fluids, then this fact
might be important for materials
processing and fluid handling in
weightlessness.
RESULTS
The goal of MFMG was to determine if
interfacial phenomena seen with
immiscible fluids could be seen with miscible fluids. The experiments had to be performed with
existing materials on the International Space Station (ISS). Honey and water were chosen as the
fluids, and urine collection syringes were used as the vessels in which the experiments were
performed. Four experiments were performed under isothermal conditions to determine: if a
stream of honey injected into water would exhibit the Rayleigh-Tomotika instability and break
into small drops or if an aspherical drop of water in honey would spontaneously assume a
spherical shape. Two sessions in which a stream of honey was injected into water while the
syringe was attached to the surface of the Commercial Generic Bioprocessing Apparatus (CGBA)
at approximately 31°C. No change in the stream shape was observed. No behavior beyond
simple diffusion was observed. We performed simulations with the Navier-Stokes equations
plus a Korteweg stress term. We estimated that the maximum possible value of the square
gradient parameter was 10-12 N for the honey-water system (Pojman 2005).
PUBLICATION(S)
Pramanik S, Mishra M. Linear stability analysis of Korteweg stresses effect on miscible viscous
fingering in porous media. Physics of Fluids. 2013;25:074104. doi: 10.1063/1.4813403.
ISS008E18731 – View of a syringe connected to a drinking
straw containing a mixture of honey and water for the
Miscible Fluids in Microgravity.