Frequently, hazardous bacteria left on plates, bowls, and silverware are not completely destroyed by conventional dishwasher. They also need lengthy cycle periods, which consume a lot of electricity, and the soap is pumped in and out, which pollutes the environment.
Dishwashers that use superheated steam might be a better, more sustainable option. Researchers from the Technical Universities of Dortmund and Munich modelled such a dishwasher for the Physics of Fluids and discovered that it eliminated 99% of bacteria on a plate in just 25 seconds.
A box with solid side walls, a top opening, and a nozzle at the bottom represents the idealized dishwasher. Above the nozzle is a plate with a heat-resistant strain of bacteria on it. In the simulation, the microbes are no longer alive once the plate reaches a certain temperature threshold.
“At an extremely high velocity, steam emerges from the nozzle. We can observe shocks, and the resulting turbulent flow has eddies and vortices. ” Natalie Germann, a writer from the Technical University of Dortmund, remarked. We also include heat transfer, which shows how the temperature changes in the simulation box and how condensation forms on solid surfaces.
The surfaces in the dishwasher reflect the shock waves that are produced by the high steam velocity. Although the team’s focus in this experiment was on germs, food detritus could one day be successfully removed using shocks.
According to research author Laila Abu-Farah of the Technical University of Munich, “our study helps identify the strength of the shocks, the position of the shocks, and the vortices that are formed inside the dishwasher.” The positioning and direction of the nozzles as well as how the items or objects are arranged inside the dishwasher depend on these factors.
While the models demonstrate the bacteria’s fast inactivation, actual dishwasher applications would include more plates and take more time. The researchers still think it would be a lot faster and more efficient than current technologies.
The superheated steam dishwasher would initially cost more, but over time, the savings in water, electricity, and detergent would make up for it. It would be perfect for use in establishments with strict hygiene requirements, such as restaurants, hotels, and hospitals.
According to Germann, “We confirmed that the dishwashing application using superheated steam is promising.” This is the first study to combine phase change, fluid dynamics, heat transport, and bacterial inactivation. “Thus, it establishes the framework for additional technical work and computational research in the future.”
