DESIGN AND ANALYSIS OF HIGH-TEMPERATURE, HIGH-PRESSURE SEAL TEST RIG

As the power density of turbomachinery increases, individual components such as seals are subject to more extreme conditions. The maximum working fluid temperature and pressure are increasing, as is the operating speed. Seal performance has always had a large impact on machine efficiency, but with new working fluids and higher temperatures, this is especially true. Designing component level test rigs at these conditions presents challenges. Material compatibility at high temperatures, rotordynamics, thermal expansion, and a cooling scheme must be balanced in order to yield satisfactory designs. This paper presents the design of a new test rig capable of testing seals to 700 degrees C and 250 bar at speeds up to 21,000 rpm. The test rig measures leakage and estimates drag loss. While designed to test dry gas seals for sCO(2), the test rig can accommodate a variety of seal types, geometries, and working fluids. A direct drive 250 kW motor provides rotation to the test rig, and a separate spindle assembly provides a connection to ground. Thermal expansion in the seal housing is radially uniform due to a flexible attachment to the spindle assembly. The seal housing material is Alloy 625, and is rated for the full pressure range. Cooling is provided to the spindle shaft through an oil/air system.