Publication

A Comparison Between Foil, Herringbone-Grooved, and Tilting Pad Gas Journal Bearings

Jürg Alexander Schiffmann
2026

Abstract

Self-acting gas bearings are a popular solution for small scale turbomachinery. Many designs have been studied, and among those, the following three are very diffused and promising: foil bearings (FBs), herringbone-grooved bearings (HGBs), and tilting pad bearings (TPBs). Despite the many studies investigating these architectures individually, a direct benchmark between them is still absent. This paper proposes a side-by-side comparison of the three concepts specialized to one common application: a 14 mm rotor with a nominal speed of 150 kRPM. To achieve this, a numerical model was implemented, using a 2-D point mass rotor. Performance metrics were then calculated: static equilibrium positions and fluid film height, Campbell diagrams, logarithmic decrements, friction losses, and the full orbit response under a selected unbalance. The FB exhibits the largest fluid film heights and lowest losses, but higher rotor eccentricities; the HGB shows minimal eccentricities with higher losses; and the TPB provides superior dynamic stability, also at the expense of higher losses.

Official source

https://infoscience.epfl.ch/entities/publication/1b1334db-9fd2-40f4-9f10-7acbb974b593

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Jürg Alexander Schiffmann
2026

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/1b1334db-9fd2-40f4-9f10-7acbb974b593

About this result

Related concepts (32)

Fluid bearing

Fluid bearings are bearings in which the load is supported by a thin layer of rapidly moving pressurized liquid or gas between the bearing surfaces. Since there is no contact between the moving parts, there is no sliding friction, allowing fluid bearings to have lower friction, wear and vibration than many other types of bearings. Thus, it is possible for some fluid bearings to have near-zero wear if operated correctly. They can be broadly classified into two types: fluid dynamic bearings (also known as hydrodynamic bearings) and hydrostatic bearings.

Friction

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities (see Figure 1).

Thrust bearing

A thrust bearing is a particular type of rotary bearing. Like other bearings they permanently rotate between parts, but they are designed to support a predominantly axial load. Thrust bearings come in several varieties. Thrust ball bearings, composed of bearing balls supported in a ring, can be used in low thrust applications where there is little axial load. Cylindrical thrust roller bearings consist of small cylindrical rollers arranged flat with their axes pointing to the axis of the bearing.