What is the term for an orifice plate with a round opening that is centered in the middle?

The term for an orifice plate with a round opening that is centered in the middle is "concentric orifice." This description specifically refers to the design where the circular opening is symmetrically positioned, allowing for uniform flow characteristics through the orifice. A concentric orifice is typically used in flow measurement to ensure that the fluid passes evenly through the opening, facilitating accurate readings and consistent performance.

In contrast, an eccentric orifice has an opening that is offset from the center, which can alter the flow pattern and is suitable for specific applications where disturbed flow is necessary. Other terms like "concentric flange" or "centralized flow" do not accurately describe the geometry of the orifice plate itself or may refer to different components in fluid dynamics. Thus, the correct identification of a concentric orifice is essential for understanding fluid flow systems.