Synopsis: Convection Speeds Up on a Slant

Convective mixing of fluids goes faster when the container is tilted—a finding that may impact the choosing of geological sites for carbon dioxide storage.
Synopsis figure
P. A. Tsai et al., Phys. Rev. E (2013)

A potential strategy for reducing greenhouse gas emissions is to capture carbon dioxide (CO2) and store it underground. One of the most promising storage options for carbon capture and sequestration (CCS) is offered by deep saline aquifers, which are brine-filled reservoirs covered by a cap of impermeable rocks. A new experimental study reported in a Rapid Communication in Physical Review E looks at how convection in the CO2-brine mixture can help trap the greenhouse gas. In particular, the authors find that a sloping saline formation could promote convection and thus provide better storage than a horizontally level one.

Deep saline formations offer a large storage capacity. Ideally, the carbon dioxide will dissolve and get trapped into the brine. However, CO2—being less dense than brine—will rise upward and may form a separate top layer that restricts dissolution, except at the boundary between the two fluids. In this situation, convection could provide much-needed stirring. Previous studies have shown that, under certain conditions, CO2-rich brine at the boundary will sink downwards in convective plumes that force fresh brine upward into the CO2.

Peichun Amy Tsai and her colleagues from Princeton University, New Jersey, investigated convection in a laboratory model of a saline formation. Unlike previous work, they considered the effect of slanted boundaries, as found at some potential CCS sites. The team poured water and propylene glycol (as stand-ins for CO2 and brine) into a pore-filled container with transparent walls. They filmed the formation of convective plumes and found that tilting the container by 20 degrees increased the rate of dissolution by 20 percent. This enhancement is analogous to the faster sedimentation of suspended particles in a tilted tube (known as the Boycott effect). – Michael Schirber


Announcements

More Announcements »

Subject Areas

Fluid DynamicsInterdisciplinary Physics

Previous Synopsis

Nanophysics

Can’t Burst This Bubble

Read More »

Next Synopsis

Interdisciplinary Physics

Alice and Bob Go Nonlinear

Read More »

Related Articles

Synopsis: Flocks Without Memory
Biological Physics

Synopsis: Flocks Without Memory

Moving particles with no memory can group together in complex flock configurations using only instantaneous cues.   Read More »

Viewpoint: Superfluids Hit the Street
Atomic and Molecular Physics

Viewpoint: Superfluids Hit the Street

A flow pattern dubbed the von Kármán vortex street, which is renowned for its aesthetic beauty and extreme power, has been created in a superfluid. Read More »

Synopsis: Wetting Matters When Emptying a Tank
Fluid Dynamics

Synopsis: Wetting Matters When Emptying a Tank

The speed at which water drains out of a tank depends on the affinity of water with the outside surface of the orifice through which it drains.   Read More »

More Articles