The paper discusses the advantages of fan performance and efficiency measurements on standardized test rigs in a pressure vessel. The resulting ability to control the ambient pressure allows a decoupling of the Mach and Reynolds number and extends the achievable Reynolds number range. Thus, Mach number effects (the compressibility of the flow) and Reynolds number effects (the change of friction losses) are investigated independent of each other. The design of the pressurized test rig and the results are presented as well as the validation of scaling methods recently developed at Technische Universität Darmstadt. The here introduced concept of a pressurized test rig may serve an elegant approach to product validation in testing small-scaled models at full scale Reynolds number.

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