Hydrodynamic Thrust Bearings

Unlike the standard bearings that you are probably used to, the hydrodynamic thrust bearing is a type of bearing that is designed to reduce the energy consumed during the rotation of the shaft. It also helps to improve the life of the bearing.

Understanding the rotor's orbits

Using an axisymmetric shaft supported by a cylindrical lubricated journal bearing, we studied the behaviour of an unbalanced flexible rotor. The hydrodynamic thrust bearing model allows us to study the dynamic behaviour of a rotor bearing system at different rotor speeds. Using this model we performed numerical simulations to better understand the rotor's orbits.

First, we considered the motion of the rotor disc and shaft in relation to the hydrodynamic film pressure. When we look at the hydrodynamic film pressure we see that it increases with the rotor's velocity. This increases the pressure on the film between the bearing cone and bearing foils, which is an important factor in determining the behaviour of the rotor's bearings. The film also acts as a non-linear elastic cushioning on the rotor foils.

We also investigated the behaviour of the bearing foils and the bearing cone in relation to each other. We found that the foils tend to flex outward in a manner similar to the film's squeeze. This is due to the compliancy of the bearing foils.

Groove length ratio

During the design of a hydrodynamic thrust bearing, the groove length ratio should not be neglected. It plays an important role in determining the SGTB's hydrodynamic response. Increasing the length of the grooves decreases the friction torque. It also increases the efficiency of the bearing.

The groove length ratio is one of the most important factors affecting the efficiency of the thrust bearing. This is due to the fact that the efficiency of the bearing will be largely determined by the pressure distribution in the bearing. The pressure distribution is obtained from the solution of the Reynolds equation. The Reynolds equation describes the oil film pressure distribution. Moreover, it also contains the oil film's temperature distribution.

The efficiency of the SGTB is also determined by the design of the groove pattern. The best groove pattern should be capable of producing the highest efficiency. For example, it should have sufficient load support, a high load carrying capacity, and provide good thrust bearing performance.

Non-Newtonian lubricant behaviour

Various investigations have been carried out on non-Newtonian lubricant behaviour in hydrodynamic thrust bearings. These studies have examined the effect of non-Newtonian behaviour on bearing performance indices.

Non-Newtonian lubricant behaviour is characterized by a non-linear viscous behaviour, which results in non-linear behaviour in bearing performance. Typically, non-Newtonian behaviour causes a lower friction coefficient, higher load capacity, and higher dynamic coefficients. Hence, the use of commercial lubricants that exhibit non-Newtonian behaviour can be beneficial in determining the performance of hydrodynamic thrust bearings.

The non-Newtonian behaviour of lubricants can also be used to increase the damping properties of slider bearings. These bearings are generally used in high speed rotating machines. Hence, it is essential to know the non-Newtonian behaviour of lubricants in order to improve the dynamic stiffness of these bearings.

Non-Newtonian rheology in journal bearings can be studied using the Rabinowitsch fluid model. This model can be applied to Newtonian lubricants as well as dilatant lubricants. The Reynolds equation can also be used for lubrication analysis of journal bearings.

Reverse loading on bearings on single-acting pumps

Choosing the right design for hydrodynamic thrust bearings on single-acting pumps requires a number of design constraints. First, a hydrodynamic bearing must be compatible with the impeller. Second, it must operate within a certain speed range. Third, the bearing must be able to withstand the thrust load. In addition, the bearing must be designed to be lubricated.

The hydrodynamic bearing must also be able to withstand axial deflection under load. Choosing the right size of bearing gap is essential. The size of the gap must be small enough to provide the desired radial stiffness. The bearing must be free of stagnant areas that cause blood clotting.

Bearings must also be designed to withstand cyclic loading and stop-start motions. Geometric discontinuities in the bearings can also influence the dynamic response of the rotor-bearing system.

It is desirable to have constant axial stiffness for dynamic analysis. It is also desirable to have a linear force displacement characteristic. However, resonance reasons could limit the stiffness of the thrust bearing.