About Blower Components

Blower Types

All blowers consist of an impeller and some form of housing. The impeller has a set number of equally spaced blades that, when rotated about an axis, pull fluid inside of the device. The centrifugal forces on the fluid increase the pressure inside of the blower's housing.

Blowers can differ in how they expel fluid, based on their housing designs. The housing design of some blowers allows the fluid to exit around the circumference of the blower (that is, radially), while introducing swirl into the fluid flow. In the case of some centrifugal blowers, a built-in outlet duct facilitates fluid exiting the blower at a 90° angle. The Fluid Model Creation app supports the circumferential outlet type of blower.

All blowers have a fan hub, which is the part of the blower's housing that covers the center of the impeller. The fan radius and the fan hub radius determine the cross-sectional area for fluid intake.

Impeller Blade Angle

An impeller's blade angle affects the efficiency of the blower as well as the nature of the fluid flow.

Fan Curves

A fan curve is a data set used to model the performance of a blower. You can plot the change in pressure, dependent on the change in the volume flow rate, and interpolate the data to graph a curve.

Derating Factor

You can run a blower below its maximum capacity to reduce noise and increase its lifetime but still achieve its thermal cooling requirements. Blowers run at less than maximum capacity by reducing their revolutions per minute (RPM), which derates the fan curve. The derating factor simulates this reduction of the fan curve.