Why do automatic washing machines use laundry detergent?

Automatic washing machines can use both washing liquid and washing powder, because the washing machine is decontaminated by the scouring of water flow and the friction between clothes and drum, and has nothing to do with detergent.

Extended data

The washing process of automatic washing machine is mainly to pull dirt into the water under the mechanical action of drainage and washing produced by machinery and the wetting and dispersion of detergent to achieve the purpose of washing.

First of all, the washing liquid filled between the blades of Apollo wheel is thrown to the barrel wall at high speed under the action of centrifugal force and rises along the barrel wall. In the center of the impeller, because the thrown liquid forms a low pressure area, the washing liquid flow echoes around the impeller. In this way, an eddy current centered on the impeller axis is formed near the impeller. Under the action of eddy current, the clothes make a spiral rotation, are sucked into the center and then thrown to the bucket wall, and rub against the bucket wall. Because the center of the pulsator is a low-pressure area, clothes are easily sucked near the pulsator and constantly rub against the pulsator, just like rubbing clothes manually, and dirt is forced to leave the clothes.

Secondly, when clothes are put into the washing liquid, due to the slow inertia movement, there is a speed difference between the water flow and the clothes, which makes them move relatively, and the water flow rubs against the clothes relatively, which also helps the dirt to leave the clothes. Thirdly, due to the irregular shape of the washing surge, when the rotating water hits the barrel wall, its speed and direction change, forming turbulence. Under the action of turbulence, the clothes move irregularly and roll, and their fibers are constantly bent and twisted, and the clothes rub against each other, which increases the effective area of washing and improves the uniformity of washing.