Final answer:
The correct shape for constructing a centrifugal fan housing to convert velocity pressure to static pressure is a scroll shape, which utilizes conservation of angular momentum to redirect airflow effectively.
Step-by-step explanation:
To convert velocity pressure to static pressure in a centrifugal fan housing, the correct construction shape is a scroll shape. This design allows for a gradual deceleration and redirection of the airflow, which reduces the kinetic energy of the velocity pressure and converts it into increased static pressure. The scroll shape is effective because it utilizes the principle of conservation of angular momentum, and provides a path for the air to slow down and change direction without backflow or excessive turbulence.
The scroll shape corresponds to the concept that the force exerted on the fluid by the fan is always perpendicular to a stationary fluid, and pressure exerted by the static fluid is a scalar quantity exerting force perpendicular to any surface. Additionally, centripetal force plays a significant role in this process, as it is perpendicular to the tangential velocity and causes uniform circular motion, which is central to the function of a centrifugal fan.