AIRFLOW DEMONSTRATION EQUIPMENT

Measuring Air Flow to BS1042 and BS848

	As well as schools, colleges and universities an ever increasing number of industries use moving air and gases as part of processes such as combustion, heat transfer, cooling, drying, conveying, etc. It is essential for designers and engineers in these industries to have a working knowledge of the principles of airflow measurement, and to be familiar with the instruments and techniques involved.
	The opportunity to observe and to participate in practical work make a valuable contribution towards the students' firm grasp of the principles involved. A comprehensive manual of suggested experiments, dealt with in depth, is supplied with the equipment.

The Airflow Demonstration Set is built round a forward curved centrifugal fan running at approximately 2800 rev/mm on 50 Hz, 3400 rev/mm on 60 Hz. The fan will move up to 0.26m3/s (550 cfm) through the equipment when fitted with a 375 W, 50 Hz motor or 0.35 m3/s (750 cfm) with a 750 W 60 Hz motor.
The fan takes in air through a 140mm diameter duct, at the mouth of which is the conical inlet device (BS 848). From the fan, the air passes through a clear perspex rectangular duct, 127mm x 114mm, at the end of which is a modified ellipsoidal nose pitot static tube (National Maritime Institute Laboratory Report 17863) carried in a traversing slide.
This arrangement allows measurements to BS1 042. Through a square to round transformer piece the air flows into a length of circular ducting which straightens the flow on its approach to the venturi tube (BS1042). Following this is an orifice plate (B51042) with 1 D and 0.5D tappings provided, and the Set is terminated with a spinning damper permitting extremely fine adjustment of flow rate.

ACCESSORIES

Refer to Anemometer and Electronic/Test Manometer sections for complimentary instrumentation.

We suggest the AV6 Anemometer/Logger and MEDM 5K Micromanometer.

Supplementary Set

This comprises two separate bends and two additional lengths of rectangular duct, together with a square to round transformer piece. With these items it is possible to examine the pressure distribution around bends, and compare losses created by the easy (swept) bend with the losses of the mitred (right angle) bend.

Swinging Stator Dynamometer

When fitted to the fan in place of the standard motor, the dynamometer allows determination of shaft power to be made, permitting efficiency calculations.