The Centrifugal Fan Teaching Unit, "HVCB", allows the students to study the operation characteristics of a centrifugal fan. For that purpose, the unit carries out the measurements of flow, speed, temperature and humidity. Multiple tests related to air flows can be performed with the accessories.
The main element of this unit is a variable speed centrifugal fan, which is measured through a speed sensor, and a wattmeter determines the power consumed by the fan.
The unit also includes an aspiration duct and a discharge duct, both transparent. Two butterfly valves, placed in the inlet of the aspiration duct and at the outlet of the discharge duct, regulate the air flow.
The transparent aspiration duct has an orifice plate to calculate the air flow through a inclined manometer.
There is other inclined manometer to measure the differential pressure between inlet and outlet.
The unit is supplied with a set of three interchangeable turbines to study and analyse the influence of the blades shape:
- With the blades curved forwards.
- With the blades curved backwards.
- With perpendicular blades.
There are also humidity, pressure and temperature measurements to know the inlet air conditions.
- Calculation of the flow with the orifice plate.
- Calculation of the typical curve of a fan at a constant turning speed (turbine with blades curved forwards).
- Calculation of the typical curve of a fan at a constant turning speed (turbine with blades curved backward).
- Calculation of the typical curve of a fan at a constant turning speed (turbine with perpendicular blades).
- Study of the dependency on the type of turbine. Comparison of the results of the different types of blades.
- Calculation of the efficiency of the fan.
- Introduction to affinity laws for fans.
- Study of the static pressure increase.
Additional practical possibilities:
- Measurement of performance at constant speeds.
- Study and comparison of the practical results and the results calculated by the students.
Other possible practices (to be done with the Optional Models and Accessories):
- Measurement of the static pressure in a duct with one or two static pressure takings (HVCC-C1TP or HVCC-C2TP accessories).
- Measurement of the flow in a duct with one pressure taking with Pitot (HVCB-CTPP or HVCC-CTPG accessories).
- Study of the influence of straighteners (HVCC-EFCG, HVCC-EFCP or HVCC-EFS accessories).
- Study of the influence of a symmetrical shutter (HVCC-OS accessory).
- Measurement of the flow in a duct with a nozzle (HVCC-T2D accessory).
- Measurement of the pressure distribution around a cylinder subjected to transverse incident flow (HVCC-CDP accessory).
- Measurement of the pressure losses in different pipe elements (HVCC-TA accessory).
- Study of the effect of differently shaped pipe inlets (HVCC-TA accessory).
- Study of a cooling curve (HVCC-TC accessory).
- Determination of the heat transfer coefficients from the cooling curve (HVCC-TC accessory).
Additional practical possibilities (Optional Models and Accessories):
- Measurement of the total pressure in the wake of a cylinder (HVCB-CDP and HVCC-CTPG accessories).
- Determination of the drag coefficient from the pressure distribution in the wake of a cylinder (HVCC-CDP and HVCC-CTPG accessories).
- Demonstration of the wake depression (HVCC-CDP and HVCC-CTPG accessories).