Date of Award


Document Type

Union College Only

Degree Name

Bachelor of Science


Mechanical Engineering

First Advisor

Bradford Bruno


Diffusion, Porous, Flow, Experimental, Analytical, Differential Equation, Matlab, Stumpf


The goal of this project is to understand how fluid flows into, out of, and through silica aerogel monoliths. An aerogel is a material that is up to 99% air by volume and has unique properties including a high surface area, low density, good insulating properties, and good thermal stability. These properties introduce a variety of different applications that aerogels can be used including using aerogels as insulation between glass window panes, using aerogels for internal combustion engine exhaust cleanup, and using aerogels in filtering applications.

To determine their full potential within these projects, fluid flow through aerogels must be investigated. Diffusivity is a property that allows the amount of flow through a monolith sample to be related to the gradient driving the flow. To measure the diffusivity of aerogels, a device based on a design by Stumpf et al. is used. The device allows a known quantity of gas to be introduced into an evacuated aerogel chamber and the pressure of the aerogel chamber as the gas permeates the aerogel monolith is recorded. Then, a 2D transient differential diffusion equation solution is plotted against the experimental curve and the diffusivity value is varied until the two curves reach the equilibrium pressure at the same time.

The obtained diffusivity values for silica aerogel monoliths are on the order of 10-5 m2/s, which agrees with already published results. Soon, the device will be used to determine the diffusivity of non-silica aerogels as these values are not available in literature.