Aircraft Research Association

ARA

Propulsion Simulation

Introduction

ARA has considerable experience in propulsion simulation for both Civil and Military applications and has developed a wide range of test techniques and facilities for investigating the aerodynamics of power plant installations and power dependent aerodynamic interactions. A small selection of the equipment available is introduced below:

Turbine Powered Simulators (TPS units)

TPS Animation

Powering Nacelles with TPS units allows representative inlet and exhaust conditions to be simulated.

TPS units can be installed on both full and half models.

The TPS units are powered by high pressure air. They run to maximum speeds from 45,000 rpm to 80,000 rpm dependent on size, and a sophisticated oil feed system is employed for bearing lubrication.

Air Motors

A400m half model props

A range of air motors is available for isolated or installed small scale propellers 0.4 m (1.3ft) in diameter. Due to the space required inside the model for the air pipes, these air motors must be installed on half models.

Isolated Cowl Test Rig

Isolated Cowl Rig

A special rig (illustrated opposite) has been devised to measure the internal and external performance of isolated cowls for civil transport applications.

Internal engine face pressure measurements are made with a rotating pressure rake.

Internal mass flows are derived from a downstream venturi as well as the engine face pitot/static measurements.

External drag is measured by a rotating 5 arm rake of pitot/static tubes using the momentum deficit method.

Both rake drives are continuous, providing small rotation increments for optimum coverage of both internal and external flows.

The incidence variation is ±6˚. This can be extended to ±25˚ at low Mach numbers for internal pressure measurements.

Tunnel blockage is 1% at zero mass flow and 0.4% at mass flow ratio = 1.

Inlet flow is induced through the rig by connection to a 9.7MW (13000hp) compressor. This ensures that the mass flow control is independent of free stream conditions and allows high mass flows at low Mach number and ground running operations to be investigated.

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