Wax Experiments and Lava Tubes


DOEI Project Funded: 2006

We need to answer the following questions:

  1. Is there is a minimum flow rate, which would result in a frozen channel if reduced? No minimum is reported yet, but one would think that a very sufficiently small flow would not supply enough heat to counteract conductive cooling. We plan to conduct two or three runs to establish a minimum flow rate instead of the five to ten originally planned.

  2. What is the nature of a theory predicting the width of this channel? The theory must be developed. See below for details. Probably we will be unable to develop the theory.

  3. What is the 3-d lava tube analog of this experiment? We have a hollow cylinder with cooled walls. Wax inside this flowing along the axis might form a melt tube. We want to try and inject wax at one end of the tube and try and for a circular tube of melt. This experiment is a priority and will be conducted.

  4. Is there are theoretical limit to the distance lava can travel? As outlined above the tentative theory exists which we need to confirm, improve or discard. We may not be able to develop this theory.

Specifically, we propose to continue these experiments and not continue with theory.  We will vary the flow rate of the peg wax and temperature of the cold bath. In addition, a new tank is desired with flow of wax through a hollow pipe that is cooled from the outside. Money for materials (wax, metal, plastic, tubing and containers, $3000) is included in the budget. Fabrication will be done by a Research Associate, (1 month) and the experiment will be conducted by the PI (about a week)  We predict that the hot wax will adopt a flow channel with a circular cross-section inside of a solid rim of wax as a model of a lava tube within the earth. The shape and width of this channel can be measured through a broad range of parameter space, which then allows scaling up to full sized lava flows.

On my own time, I will continue to develop simplified analytical descriptions of reactive and solidifying flow processes in order to characterize the essential physics of flow localization.