This paper describes the operation of a continuously operating cold flow test stand for axial turbine stages. The interesting feature of this test stand is the fact that the power generated by the test turbine is used for driving a compressor, which supplies additional air to drive the turbine. The brake compressor was a donation from industry and was a very welcome alternative to a water brake. The advantages of using this compressor lie in the low installation costs and the power savings. The performance of the test turbine stage influences the capabilities of the test stand. A suction blower driven by a helicopter engine can be used to decrease the exhaust pressure allowing to increase the turbine expansion ratio.
The performance of the whole test facility and the complex interaction of the components will be described. In general, design engineers are interested in the performance of their test stages at different operating conditions (i.e. corrected speed, pressure ratio). It will be shown by which control mechanisms different operation points can be obtained and which range of the values can be achieved.