Optimum Hydrodynamic Journal Bearing Performance Characteristics in High-Speed and High-Power Gearboxes
- PDF / 944,273 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 1 Downloads / 183 Views
CASE STUDY
Optimum Hydrodynamic Journal Bearing Performance Characteristics in High-Speed and High-Power Gearboxes Sivakumar Dakshinamurthi1
•
Suresh Nagesh2
Received: 18 May 2020 / Accepted: 18 September 2020 Ó The Institution of Engineers (India) 2020
Abstract Application of hydrodynamic journal bearings such as pressure dam and offset in high-speed and highpower gearboxes face immense challenges to deliver optimum static and dynamic performances under various operating conditions. Stability, efficiency and oil flow are critical to quality (CTQ) requirements for these gearboxes, and hence, optimum design of journal bearings is required to meet all the performance requirements. For example, bearings designed for optimum static performance at full load and full speed conditions could not deliver the stable dynamic performance at no load conditions. In this study, offset and pressure dam geometries are combined into same bearing and analyzed if the combination can deliver the optimum performance characteristics. The governing mathematical models of Reynold’s equation and energy equation include turbulent and adiabatic thermal effects. The analytical study found that combined offset pressure dam bearing delivers optimum performance at all operating conditions.
Cxy, Cyx D FxF y GxGz H h Kxx, Kyy Kxy, Kyx L Ld m P p RJ Re T T uw u; w
Keywords Hydrodynamic bearings Stability Fluid film And gearbox
y z h l lin
List of Symbols cp Specific heat capacity of the oil, kJ-kg/K CR Radial clearance at split line, mm Cp Crown clearance, mm Cxx, Cyy Direct damping, N-s/mm
l w q k
Cross-coupled damping, N-s/mm Journal diameter, mm Bearing reaction force, N Turbulent coefficients Dimensionless film thickness (h/CR) Film thickness, mm Direct stiffness, N/mm Cross-coupled stiffness, N/mm Bearing length, mm Pressure dam width, mm Bearing preload, (1- CR/Cp) Dimensionless pressure (p*CR2/ l*x*RJ2) Oil film pressure, Pa Journal radius, mm Reynolds number Temperature, deg C T/TIn Relative temperature Velocity in circumferential and axial, m/s Dimensionless velocity component in circumferential (u/xRJ) and axial (w/xRJ) Y/h, Dimensionless coordinate across film Z/RJ, Dimensionless coordinate in axial X/R, Dimensionless circumferential coordinate Dynamic viscosity of the lubricant, Pa-s Dynamic viscosity of the lubricant at oil supply temperature Tin l/lIn Relative dynamic viscosity CR/RJ Relative radial clearance Density of the lubricant, kg/m3 Thermal conductivity of the lubricant, W/mK
& Sivakumar Dakshinamurthi [email protected] 1
PES University, Bengaluru 560085, India
2
CORI Lab, PES University, Bengaluru 560085, India
123
J. Inst. Eng. India Ser. C
Introduction High-speed and high-power gearboxes are being used in various turbo machinery applications such as alternators, compressors, fans and pumps. They are required to run at various speeds and loading conditions depending on the application requirements. The surface velocity of journal bearings used in these gearboxes varies from 35 to 100 m/s and
Data Loading...
