The unit is designed for blow or suction induced flow and can be assembled for operation in either the upward or downward mode, whichever is most convenient. The Aeroweb honeycomb matrix is suspended within a cylindrical, aluminum housing with the skirt of the matrix immersed in an annular oil reservoir in the base which serves both as an air seal and a viscous damper. A set of weights is provided with the instrument to facilitate static calibration of the strain gauge with an accuracy of 2%. The matrix is mounted on an axle in the frame and supported by precision ball bearings while the torque arm connected to the axle acts on a Wheatstone Bridge strain gauge transducer. Cussons Display Unit, used in conjunction with the swirl meter, is a mains operated instrument complete with power supplies, which converts the strain gauge measurement into a four element, LED digital readout.
Application:
In automotive and truck size engines for instance, a pressure drop of 254 mm water gauge is normally used. The illustration shows a typical test rig layout arranged for downward air flow, in which the clients manometer registers a constant pressure drop across the model which must always be high enough to ensure fully turbulent flow in order that the results can be applied to his own particular engine configuration.
A low range strain gauge transducer measures the positive or negative force caused by the torque reaction produced when swirling air is straightened by the honeycomb. This torque is normally calibrated over a small range for higher accuracy.
The display unit contains the signal conditioning electronics in a rack mounting module.
The front panel carries the 4 digit LED display, a main on/off switch and zero and span potentiometers. The rear panel connections include a 10V analog signal for connection to the data acquisition system.
The matrix is connected via a torque to a strain gauge transducer which is calibrated by suspending weights over pulleys either side of the torque arm.
The length of torque arm is such as to enable torque values up to 0.1Nm to be The unit shall be arranged for flow in an upward and downward direction and is supplied complete with adaptor plate having a pilot bore of diameter 50mm.
Swirl meter comprises a Honeycomb matrix mounted within cylindrical housing.
The dimensions of individual cell of the matrix being suitable for arresting the swirl of the incoming air
Consists of a fabricated steel frame bench mounted on casters, which house the major components Control, instrumentation and data acquisition is mounted on the frame in one 3U high, 19 wide electronic rack enclosure.
Intended for use with port models with a nominal free air capacity of 50 litres/second.
It is used for blowing or drawing air through the cylinder head port model. The mode of control may either be direct fan speed set point or by the test piece pressure drop set point. A variable speed centrifugal fan/blower unit, capable of 100mBar static pressure and a flow rate of 300m/hr, is attached to a base plate on the bottom level of the frame.
The impulse swirl meter uses a swinging honeycomb type matrix which is restrained from rotation by a strain-gauged load cell to totally arrest the angular swirl component thereby measuring the resultant angular impulse as a torque. Earlier methods of measuring swirl such as swirl vane meters, were dependent on the velocity profile of the air stream, whereas the impulse type of meter overcomes this limitation by responding to the total angular momentum flux in the swirling air flow.
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