As a part of the Honors Engineering Program at CSU Long Beach, we had the opportunity to write a thesis on any topic of our choosing. At the time, I was doing lab work helping to characterize the fluid dynamics of white holes experimentally and analytically and decided it would be interesting to combine two of my interests for my thesis; fluids and coffee.
This paper investigates the effect of mechanical stirring techniques on convection for coffee. This is achieved by analyzing the effects of 4 different stirring patterns against a control and evaluating each method's total cooling time and time constant. A robotic arm was utilized to get reliable data and a cylindrical coffee stirring straw was used as the primary coffee stirring device. Data was collected at 4 sensor locations; one roughly in the middle of the stirring straw, one at the bottom of the stirring straw, and two on either side of the cup located 180° from each other. The patterns that were analyzed were a one-directional circle, a line, an alternating circle, and a figure-eight. Each experimental trial started at 80 °C and ended at 55 °C. The results demonstrated that an alternating circle pattern had the fastest average cooling time and average time constant across each sensor.
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