Nanofluids for Displacement of Entrained Contaminants from Restricted Geometries
Abstract
Liquid-phase chemical warfare agent can become entrained in constrained geometries (capillary features) on military assets (e.g., screw threads or between mated surfaces). If the liquid contaminant wets the solid, capillary forces stabilize the contaminant, and conventional decontaminants are ineffective. This work seeks to leverage research in the field of enhanced oil recovery, in which nanofluids are used to displace oil trapped in underground rock formations. Two types of nanofluids are studied here: (1) a reactive, sodium-based nanofluid and (2) silica and polyethylene glycol (PEG)-based nanofluids that promote contaminant dewetting. It was found that the sodium nanofluid is effective at displacing contaminant by gas bubble formation and expansion, providing a force that pushes against the contaminant. The silica- and PEG-based nanofluids were effective at dewetting contaminant from capillary walls relative to aqueous surfactant-based controls but did not remove the contaminant from the capillary. It was found that the silica nanofluids form a pore network upon water evaporation, and contaminant trapped in an adjacent capillary can be passively pulled out of the capillary feature into this pore network. Further study of this mechanism and how it can be coupled with the dewetting capability of silica nanofluids is suggested.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 06, 2023
- Accession Number
- AD1198339
Entities
People
- Adam R. Hinkle
- Brent A Mantooth
- Jill Ruth
- Mark J. Varady
- Melissa L. Sweat
- Melissa S. Hulet
- Neil Hawbaker
Organizations
- Defense Threat Reduction Agency
- United States Army Combat Capabilities Development Command