Fans are key components of ventilation systems, providing ventilation, cooling, drying or pneumatic transport. For optimum design of such systems, it is important to know the characteristic variables of a fan.
It investigates a radial fan. This trainer determines the interdependencies between the head and flow rate as well as the influence of the fan speed on the head and flow rate.
The radial fan aspirates the air in axially from the surrounding environment. The high-speed rotating rotor accelerates the air outwards. The high velocity at the outlet from the rotor is partially converted into pressure energy in the spiral housing. The vertical pipe section is connected to the spiral housing. A Venturi nozzle to measure the flow rate and a throttle valve to adjust the flow rate are inserted into the pipe section. An iris diaphragm can optionally be used. Its variable cross-section enables simultaneous adjustment and determination of the flow rate. The effective pressures to calculate the flow rate are read from liquid column manometers. The head of the radial fan is likewise measured by liquid column manometers. U-tube manometer, single tube manometer and inclined tube manometer with graduated measuring ranges are available.
Learning Objectives And Experiments
- Setup and principle of a radial fan
- Plotting fan and system characteristics
- Flow rate measurement methods based on the differential pressure method using:
- Iris diaphragm
- Venturi nozzle
- Comparison of both measurement methods
- Familiarisation with various differential pressure gauges
- Determining efficiency
Specification
- Radial fan as turbomachine
- Iris diaphragm or Venturi nozzle to determine flow rate via the differential pressure
- Speed adjustment by frequency converter
- U-tube manometer, single tube manometer and inclined tube manometer measure the differential pressure
- Air flow rate in pipe section adjustable by throttle valve or iris diaphragm
- Speed, torque and electric power capacity digitally displayed
Technical Specification
- Radial fan
- Max. Power consumption: 370W
- Max. Pressure difference: 860Pa
- Max. Volumetric flow rate: 4m3/min
- Nominal speed: 3000min-1
- Speed range: 1000…3000min-1
- Iris diaphragm adjustable in 6 stages
- Diameter: 40…70mm
- K=1,8….7,8
- Venturi nozzle
- Air inlet diameter: 100mm
- Pipe neck diameter: 80mm
- K=7,32
- Measuring ranges
- Differential pressure:
- 30…0…30mbar (U-tube manometer)
- 0…15mbar (single tube manometer)
- 0…50Pa (inclined tube manometer)
- 230V, 50Hz, 1 phase
- 230V, 60Hz, 1 phase; 230V, 60Hz, 3 phases
