The Whip and Whirl Test Rig was designed to operate up to 8000 rpm, reaching an instability state at about 5000 rpm. The rig was designed to evaluate the dynamic response of annular seals/bushing operating under oil whip and whirl conditions in a turbulent flow regime (water lubrication). The in-between bearing design has a 4” diameter shaft at the seal. The original design changed from a back-to-back seal/bushing design, to a single element, to eliminate the possibility of skewing the results by the shaft touching off unevenly at each seal/bushing. The same stator with the back-to-back is used in the test rig, therefore one seal/bushing was designed as a “dummy” element. This seal/bushing has a larger clearance, centrifugal grooves, and swirl brakes with very low stiffness and damping to almost eliminate the dynamic effect on the system. The rig is set up to capture temperature, pressure, preswirl, and displacement data. There are currently three different preswirl insert designs to simulate different levels of inlet circumferential flow.
