Two Stage Axial Flow Fan Demonstration Unit Model GFM 42

Sci-tech Two Stage Axial Flow Fan Demonstrator Trainer Model GFM 42 allows the investigation of a two-stage axial fan. A measuring device is used to determine the pressure and velocity distribution.

Item Description

Axial fans are connected in series in plants to increase the pressure. In theory, connecting two fans in series doubles the pressure increase. The trainer includes a measuring section with two identical axial fans. The carefully designed nozzle contour and a flow straightener at the air inlet ensure a uniform velocity distribution with little turbulence in the measuring section. The rotors are equipped with individually adjustable blades to change the angle of attack. The fans are equipped with outlet guide vane systems. These guide mechanisms redirect the angular momentum of the outflow in the axial direction and allow an increase in pressure. A pipe bend may optionally be installed to rotate the flow at the outlet of the measuring section. One of the fans can be removed from the measuring section so that the remaining fan can be studied in individual operation.
In the measuring section there are measuring connections to detect the differential pressures and temperatures. The flow rate is measured via an inlet nozzle. The differential pressure and the angle of attack are detected radially at rotors and guide vane systems by means of the 3-hole probe. This enables the display of different pressure and velocity profiles. The measured values are read from digital displays and can at the same time be transmitted (optionally) via USB directly to a PC where they can be analyzed using the software included.
The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Technical Specifications

▪ investigate two-stage axial fan
▪ 2 identical single-stage fans in series configuration or individual operation
▪ individually adjustable blades
▪ fans both with variable speed via frequency converter
▪ flow-optimised nozzle and flow straightener for smooth, low-turbulence flow
▪ air flow in the pipe section can be adjusted via throttle valve
▪ optional pipe bend at the outlet for flow deflection
▪ measuring device with three-hole probe for determining the differential pressure on rotor and guide vane system
▪ sensors for pressure and temperature upstream and downstream of each fan
▪ volumetric flow rate measured via inlet nozzle
▪ Optional Software for data acquisition via USB under Windows Vista or Windows 7


Technical Specifications
2 fans
▪ drive motor rated output: 3 kW
▪ max. pressure difference: 600 – 798Pa
▪ speed: 0…2850min -1
▪ blade angle adjustable
Measuring section inner diameter: 400mm
Measuring ranges
▪ temperature: 0…100°C
▪ differential pressure: -25…25mbar
radial position of the probe: 100…200mm
The manual describing the theoretical and practical aspects of the apparatus, operation, maintenance and analysis of results will be supplied with the equipment.

Services required
Electrical supply 440V three phase, 50 Hz.

Overall dimensions (approx.)
LxWxH without pipe outlet: 4325x970x1800mm
Length with pipe outlet: 5225mm
Weight: approx. 250kg

List of experiments
▪ determining the fan characteristic
▪ series configuration or individual operation of axial fans
▪ determining the energy balance
▪ determining the radial pressure and velocity
▪ distribution on rotor and guide vane system by means of a probe effect of the blade position