Superheated steam dishwashers may be more efficient and environmentally friendly than traditional dishwashers. Researchers created a simulation of such a dishwasher and discovered that it killed 99% of bacteria on a plate in just 25 seconds. An idealized dishwasher appears to be a box with solid sides, a top opening, and a nozzle at the bottom. A heat-resistant bacteria-covered plate is placed directly above the nozzle. The microorganisms are considered inactivated once the plate reaches a certain temperature.
Dishwashers do not always kill all of the harmful microorganisms that are left on plates, bowls, and cutlery. They also necessitate long cycle times that consume a lot of electricity, and the soap that is pumped in and out pollutes the environment.
Superheated steam dishwashers could provide a more effective, environmentally friendly solution. In Physics of Fluids, by AIP Publishing, researchers from the Technical University of Dortmund and the Technical University of Munich simulated such a dishwasher, finding that it killed 99% of bacteria on a plate in just 25 seconds.
Our study helps determine the strength of the shocks, the position of the shocks, and the vortices that are created inside the dishwasher. These things are very important for arranging the items or objects inside the dishwasher and the placement and orientation of the nozzles.
Laila Abu-Farah
An idealized dishwasher resembles a box with solid side walls, a top opening, and a nozzle at the bottom. A plate containing a heat-resistant strain of bacteria is placed directly above the nozzle. In the simulation, the microorganisms are considered inactivated once the plate reaches a certain temperature.
“Steam exits the nozzle at a high rate. We can see shocks, and the turbulent flow that is created has eddies and vortices “Natalie Germann from the Technical University of Dortmund is the author. “We also include heat transfer, which shows how the heat changes in the simulation box and the condensation on the solid surfaces.”
The shock waves, created by the high velocity of the steam, are reflected at surfaces in the dishwasher. While the team focused on bacteria in this work, the shocks could be used to effectively remove food debris in the future.
“Our study helps determine the strength of the shocks, the position of the shocks, and the vortices that are created inside the dishwasher,” said author Laila Abu-Farah, of the Technical University of Munich. “These things are very important for arranging the items or objects inside the dishwasher and the placement and orientation of the nozzles.”
While the simulations show quick inactivation of the bacteria, actual applications of the dishwasher would include more than one plate and therefore require more time. However, the researchers believe it would still be much faster and more effective than conventional technology.
The superheated steam dishwasher would be more expensive at first, but it would save money on water, electricity, and detergent in the long run. It would be ideal for use in restaurants, hotels, and hospitals that must adhere to strict sanitary standards.
“We confirmed that the superheated steam dishwasher application is promising,” Germann said. “This is the first study to incorporate fluid dynamics and heat transfer into phase change and bacterial inactivation. As a result, it lays the groundwork for future computational research and technical work.”
