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Rotating Machinery Vibration 2011 Part 10

Tham khảo tài liệu 'rotating machinery vibration 2011 part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 206 Chapter 6 pump rotor originate from journal bearings annular seals balancing drum and impeller flow fields. Most of the relevant research on impeller dynamic radial forces of centrifugal pumps is a product of the last 20 years and most of what is available in the open literature comes from two sources the California Institute of Technology and Sulzer Co. Pump Division . The work at Cal Tech has been funded primarily by NASA as part of the development of the high-energy pumps for Space Shuttle main engines. Cal Tech s work has been focused primarily on obtaining the bearing-like stiffness damping and added mass coefficients for impeller interaction forces. The Sulzer work was funded by the Electric Power Research Institute as part of a 10 million multiyear EPRI research project on improving reliability of boiler feed water pumps and began in the mid-1980s. The Sulzer work covers the interaction force bearing-like impeller stiffness damping and added mass coefficients as well as the time-dependent impeller unsteady flow forces. 1.2.1. Unsteady Flow Dynamic Impeller Forces Impeller unsteady flow dynamic radial forces are normalized using the same parameters as shown in Eqs. 1 and 3 for impeller static radial force. The corresponding dynamic force coefficient Kă is given by Eq. 4 with values listed in Table 1 that are extracted from experimental results reported by Guelich et al. 9 . Good-quality hydraulic flow-passage design . linns d rms 4 p g ti U2D2 procedures combined with precision cast or precision milled impellers should yield the low end of the ranges for K.i given in Table 1. Conversely poor hydraulic design quality and especially poor impeller dimensional control such as with cheap low-quality sand-cast impellers will tend to yield the high end of the ranges for K.i given in Table 1. The Kd ranges shown for the frequency range ÍÌ co 0.2 to 1.25 have the once-per-rev synchronous force component filtered out. The synchronous hydraulic component magnitude .