Venturi funnel can increase the flow of fluid about 2 times. The principle of operation is based on a growths venturi effect.

The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after Giovanni Battista Venturi (1746–1822), an Italian physicist.

https://en.wikipedia.org/wiki/Venturi_effect

The channels on the funnel intended for removing air from the tank.The output expansion angle is 5.30 degrees. This angle is optimal for many venturi devices.