**6.3 Validation of the mesh independence of the numerical model**

The setting is done by a graphical interface. The mesh used is a mixed mesh which understood elements of tetrahedral type with 6 nodes and hexahedral elements with 8 nodes. It's necessary to choose an appropriate mesh, consequently, a mesh independence study is carried out, and calculation results are shown in **Figure 6**. When the nodes number is greater than 4815, the evolution of the pressure stabilizes in the angular coordinate 205° of the plain bearing. Therefore, the number of nodes chosen for this numerical analysis corresponds to a number of nodes equal to 4815. The nodes number for textured bearing is 65,172. Convergence criterion of the numerical results is calculated for a maximum number of iterations

**Figure 6.** *Evolution max pressure according to the nodes number of the shaft mesh.*

of the shaft; 2: the inner wall surface of the bushing is stationary; 3: the domain is simulated by the fluid region. The slip of the interface is ignored; 4: the oil supply pressure is 0.08 MPa and supply temperature is 40°C, are set in oil supply holes;

**Item Value** Lubricant type PMA3

Specific heat capacity C (J/kg. K) 2000

) 800

/s) 17.,49

/s) 8,003

**Figure 4.**

**Table 1.**

**Table 2.**

**30**

Density ρ (kg/m<sup>3</sup>

*Parameters of the lubricant.*

Kinematic viscosity at 40 °C υ<sup>1</sup> (mm2

Kinematic viscosity at 80 °C υ<sup>2</sup> (mm<sup>2</sup>

*Mesh of the plain bearing. (a) Non-textured bearing. (b) textured bearing.*

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

*Geometrical and operating parameters of the plain bearing.*

**Item Value** Bearing diameter (mm) 100 Shaft diameter (mm) 99.91 Bearing length (mm) 70 Radial clearance (mm) 0.09 Pad thickness (mm) 4 Feed port diameter (mm) 14 Feed groove length (mm) 70 Rotating velocity N (rpm) 11,000–- 21, 000 Radial load W (N) 2000–20- 10, 000 Supply temperature ambiaente Ta (°C) 40 Supply pressure Pa (MPa) 0.08

the friction torque between the fluid and the internal surface of the bearing, we

To demonstrate the effect of the radial load on the operating performance of the non-textured and textured hydrodynamic plain bearing, such as pressure, fluid flow velocity and friction torque, the radial load is varied (W1 = 2000 N, W2 = 5000 N, W3 = 7000 N and W3 = 9000 N). The initial operating conditions of the bearing re a supply temperature Ta = 40° C, supply pressure Pa = 0.08 MPa and the rotational speed of the shaft equal to 11,000 rpm with a Reynolds number of Re = 3622.64 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

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

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

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

increasing the load from 2000 N to 9000 N leads to an increase in pressure.

to those recorded for a non-textured bearing (**Figure 10**).

used the k-ε model for the numerical analysis carried out in this study.

*Turbulent Flow Fluid in the Hydrodynamic Plain Bearing to a Non-Textured…*

**7.2 Radial load effect**

*DOI: http://dx.doi.org/10.5772/intechopen.94235*

ensure the turbulent regime.

*7.2.2 Fluid flow velocity*

**Figure 9.**

**33**

*7.2.1 Pressure*

**Figure 7.** *Textured bushing parameters.*

of 1000 iterations with a convergence criterion of the order of 10<sup>4</sup> . The solution converges when the residuals reach 10<sup>4</sup> . However, in some cases it is necessary to push the calculations to 10<sup>6</sup> .
