Nozzle

A nozzle, comprising:

• a carrying segment having a top side and a bottom side that is opposite to the top side;
• an assembling segment extending from the bottom side of the carrying segment;
• a conical frustum segment tapering from the top side of the carrying segment along a direction away from the assembling segment, wherein the conical frustum segment defines a central axis, and a surrounding lateral surface of the conical frustum segment and a plane perpendicular to the central axis have an angle therebetween that is within a range from 35 degrees to 70 degrees;
• and
• at least one ring-shaped rib formed on the top side of the carrying segment and surrounding the conical frustum segment;
• wherein the conical frustum segment, the carrying segment, and the assembling segment jointly define an airflow channel penetrating therethrough along the central axis;
• wherein the at least one ring-shaped rib has a ring-shaped trench recessed in a top edge thereof, and wherein, along a direction parallel to the central axis, a height of the conical frustum segment is two times to six times of a height of the at least one ring-shaped rib.