In release geometry, what does blockage factor refer to?

• A. The degree of obstruction along an opening.
• B. The material's viscosity.
• C. The degree of obstruction in an opening, affecting mass flow rate and whether the release is choked.
• D. The color of the leak.

Answer: (C)

Blockage factor is about how much an opening is obstructed. That obstruction directly changes the effective discharge area for a release, so the mass flow rate is reduced as blockage increases. It also determines whether the flow can become choked, because choking—flow reaching sonic speed at the narrowest point—depends on the available throat area. With more blockage, the throat area shrinks, which lowers the maximum possible flow and can alter the conditions under which choking occurs. In short, blockage factor quantifies the degree of obstruction and ties directly to both how much material can release and whether that release will be choked. Visocity or color of the leak aren’t related to this measure.