*7.2.1 Pressure*

of 1000 iterations with a convergence criterion of the order of 10<sup>4</sup>

*Tribology in Materials and Manufacturing - Wear, Friction and Lubrication*

Surface texturing of the bushing is a technique used to improve the load capacity of various tribological conjunctions, as well as to reduce frictional losses. The texture spherical shape of diameter rx = 3 mm and the depth of ry = 0.5 mm, the axial

distance between the textures d = 10 mm and their angular offsets α = 10°,

**7. Hydrodynamic and tribological performance of a hydrodynamic non-textured and textured plain bearing for the turbulent regime**

In this section, we will carry out a comparative study between two models of turbulence: k-ε model for turbulence in the vicinity of the walls and the RMS model (Reynolds shear stress) for turbulence in the vicinity and far from the walls. **Figure 8** illustrates the pressure distribution along the median plane of the plain bearing, for the k-ε model and the RMS model. Both models give the same pressure distribution. Since we are interested in examining the distribution of pressure, of

.

converges when the residuals reach 10<sup>4</sup>

**7.1 Test of the different turbulent model**

*Pressure evolution for k-epsilon model and Reynolds shear stress (RMS).*

push the calculations to 10<sup>6</sup>

**6.4 Textures parameters**

*Textured bushing parameters.*

(**Figure 7**).

**Figure 8.**

**32**

**Figure 7.**

. The solution

. However, in some cases it is necessary to

**Figure 9** illustrates the distribution of the pressure along the median plane for non-textured and textured bearing, for different radial loads. The graph shows that increasing the load from 2000 N to 9000 N leads to an increase in pressure. Significant pressures are obtained for a bearing subjected to a radial load of 9000 N. This increase reaches 65 per cent for a textured bearing. Also for a no textured bearing, the increase in pressure will reach 81 per cent by varying the radial load from 2kN to 9kN. The curves also indicate that the maximum pressure is noted in the angular position from 160° to 175°, on the other hand, in the angular coordinates at 200°, the noted pressure is lower than the supply pressure, indicating the existence rupture zones of the oil film. The rupture zones of the oil film are observed in the angular positions between 190° and 335° and also between 300° and 350°. The values of circumferential pressure are significant for a textured bearing with respect to those recorded for a non-textured bearing (**Figure 10**).

#### *7.2.2 Fluid flow velocity*

The fluid flow velocity according to the angular position of the plain bearing, for different radial loads is presented in **Figure 11**. The maximum flow velocity is noted for a textured plain bearing working under a radial load of 9000 N and which is of the order of 61 m/s, on the other hand is of the order of 36 m/s for non-textured plain bearing. The increase in the radial load which reacts on the bearing causes the increase in the flow velocity. This increase is estimated at 21

**Figure 9.**

*Circumferential pressure for different radial load N = 11,000 rpm (Re = 3622.64 turbulent regime).*
