What is the diffuser's primary effect on the airflow?

What is the diffuser's primary effect on the airflow?

• A. To decrease velocity
• B. To increase pressure and decrease velocity
• C. To increase temperature
• D. To increase mass flow

Answer: (B)

The main idea is that a diffuser slows the flow and converts its kinetic energy into pressure energy. As the duct expands, the air decelerates, and according to Bernoulli, the static pressure rises while velocity falls. So its primary effect is increasing pressure while decreasing velocity. It doesn’t inherently raise temperature, and it doesn’t automatically increase mass flow; the diffuser mainly recovers pressure from the flow already present.

The main idea is that a diffuser slows the flow and converts its kinetic energy into pressure energy. As the duct expands, the air decelerates, and according to Bernoulli, the static pressure rises while velocity falls. So its primary effect is increasing pressure while decreasing velocity. It doesn’t inherently raise temperature, and it doesn’t automatically increase mass flow; the diffuser mainly recovers pressure from the flow already present.