Laval Nozzle Pressure Apparatus

Item Number:

AF27 - Experiment

Demonstrates the thermodynamic and fluid mechanics of the adiabatic expansion of air through subsonic and supersonic nozzles. Includes interchangeable convergent, convergent/divergent Laval nozzles and convergent/parallel nozzle.

The apparatus connects to TecQuipment’s optional Compressor (AF27a) or a suitable laboratory supply of dry, clean compressed air.

It demonstrates the thermodynamic and fluid properties of the adiabatic expansion of subsonic and supersonic airflow through nozzles.

Its floor-standing frame holds:

A pressure chest with a removable lid and nozzle traverse mechanism;
A useful worktop;
A pressure regulator to maintain the inlet/upstream pressure, with an analog reference pressure gauge;
Three interchangeable, profiled and polished brass nozzles with mimics that fit on the traverse mechanism;
An instrument frame with digital pressure and temperature displays

Students fit a nozzle into the chest (you test one nozzle at a time). Compressed air passes through the pressure regulator and an isolating valve. It then enters the pressure chest and passes vertically down through the nozzle, then through a precision downstream valve. The airflow then settles as it passes along a horizontal pipe, through an orifice, and out to the atmosphere.

The temperature and pressure displays accurately measure temperatures and pressures at key points around the apparatus, including the pressures around the orifice, which students use to determine overall mass flow.

For ease of visibility and good engineering practice, the analog gauge also shows pressure in the chest.

A stainless-steel probe on a manually adjustable, vertical traverse measures the pressure distribution along the axis of the nozzle. A digital indicator measures the probe position in the nozzle. The traverse mechanism includes a pointer and a mounting for a ‘mimic’ of each nozzle. The pointer moves along the mimic to help students visualize the probe's position.

The instrument frame has extra space for the optional VDAS® interface unit. VDAS® allows accurate real-time data capture, monitoring, display, calculation, and charting of all the important readings on a suitable computer.

Learnnig Outcomes Key Features Essential Ancillaries

Learning Outcomes

The relationship between pressure ratio and flow for convergent and convergent/divergent Laval nozzles.
The pressure profile in convergent/divergent nozzles at various pressure ratios.
Investigation of expansion with friction in a parallel passage at high subsonic velocities.
Boundary layer growth under subsonic and supersonic conditions.
The phenomenon of choked flow corresponding to sonic velocity at a nozzle throat.

Key Features

Floor-standing apparatus that demonstrates the thermodynamics and fluid mechanics of the adiabatic
expansion of air through subsonic and supersonic nozzles
Connects to suitable laboratory compressed air supply or TecQuipment’s Compressor (AF27a)
Includes three interchangeable, profiled, and polished brass nozzles – convergent, convergent-divergent, and convergent-parallel
Built-in instrument frame and worktop
Electronic instruments measure and display multiple pressures and temperatures at the same time for ease of use and for connection to TecQuipment’s VDAS^®
Works with TecQuipment’s Versatile Data Acquisition System (VDAS^®) for instant recording of multiple readings and automatic calculations