Resurrecting the electrolytic plotting tank

Before the advent of CFD software, electrolytic plotting tanks were used extensively to plot three-dimensional heat transfer and fluid flow fields. The theory behind these tanks is the well know electrical analogy between electrical fields and temperature or flow fields based on the Laplace equation. These tanks have been essentially replaced with modern computational methods. As part of a student project, a set of small plotting tanks were designed and built to use as a heat transfer lab on two-dimensional conduction. These particular tanks have been designed to simulate a variety of boundary conditions. Readily available saline solution is used as the electrolyte. In order to simplify the plotting, and to reduce the over cost a modified common pencil is used as the probe, and the plot is made directly on a sheet of paper at the bottom of the container. Boundary conditions are simulated using up to 5 volts DC. This paper describes the development of these devices and the test results. Results have been compared to finite difference plots and to ANSYS plots to verify that the tanks are working as intended, and these results are included in the paper. The simple tanks yield results very close to the analytical methods. Also included in the paper is a brief history of electrolytic plotting tanks, the relevant theory and a description of a potential lab exercise using these tanks.