## 5 Results
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Parameters** & **Values** \\ \hline  & Load configuration & LBP \\  & Journal diameter, \(D\) (mm) & 25 \\  & Pad axial length, \(L\) (mm) & 25 \\  & Number of pads, \(N_{\text{pad}}\) (-) & 4 \\  & Pad arc angle, \(\theta_{\text{pad}}\) (deg) & 70 \\ TPJB & Pad thickness, \(t_{p}\) (mm) & 8.0 \\  & Pivot offset (-) & 0.5 \\  & Radial pad clearance, \(C_{p}\) (\(\mu\)m) & 67 \\  & Preload factor, \(m\) (-) & 0.5 \\ \hline  & Pivot type & Rocker-back \\  & Pivot’s housing radius, \(R_{h}\) (mm) & 21.0 \\ Pivot & Pivot radius, \(R_{p}\) (mm) & 18.0 \\  & Rocker-back length, \(L_{R}\) (mm) & 25.0 \\  & Young’s modulus, \(E\) (GPa) & 200 \\ \hline  & Recess type & Rectangular \\  & Circumferential length of recess, \(l\) (mm) & 5.0 \\ Recess & Axial length of recess, \(b\) (mm) & 5.0 \\  & Depth of recess, \(D_{r}\) (mm) & 0.1 \\  & Office diameter, \(d_{o}\) (mm) & 0.5 \\  & Office discharge coefficient, \(C_{d}\) & 0.68 \\ \hline  & Lubricant type & sCO\({}_{2}\) \\  & Pressure, \(P_{a}\) (MPa) & 8.0 \\  & Temperature, \(T_{a}\) (\({}^{\circ}\)C) & 37 \\  & Density, \(\rho_{0}\) (kg/m\({}^{3}\)) & 426.6 \\  & Viscosity, \(\mu_{0}\) (\(\mu\)Pa-s) & 30.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Tilting-pad journal bearing (TPJB), pivot, and recess geometries and lubricant properties. Figure 7: Three-dimensional plots of (**a**) pressure, (**b**) temperature, (**c**) density, and (**d**) viscosity for hybrid tilting-pad journal bearing with \(p_{s}=10\) MPa for each pad. Static load = 100 N, and rotor speed = 60 krpm. Figure 9 shows the centerline (a) film thickness, (b) pressure, and (c) temperature plotted against the circumferential coordinate for the supply pressures of 10, 15, and 20 MPa for the hybrid TPJB with a static load of 100 N and rotor speed of 60 krpm. The predictions for the hydrodynamic TPJB without recesses are also presented for comparison purposes. Note that the large film thickness at the recess area for hybrid TPJBs is due to  
Figure 8: Three-dimensional plots of (**a**) pressure, (**b**) temperature, (**c**) density, and (**d**) viscosity for hydrodynamic tilting-pad journal bearings without recesses. Static load = 100 N, and rotor speed = 60 krpm. the recess depth of 0.1 mm. The film thickness for hybrid TPJBs is larger than that for the hydrodynamic TPJB at the loaded pads, and it increases with an increase in supply pressure. The centerline pressure for the hybrid TPJB is also greater than that of the hydrodynamic TPJB and increases with an increase in the supply pressure for both loaded and unloaded pads. The pressure drop is attributed to the inertia effects at the boundary edges of the recess, as experimentally obtained in Ref. [39]. The pad tilting angle, pivot radial deflection, and maximum pivot stress for different supply pressures are provided in Appendix A. The pad tilting angle generally decreases, and the pivot deflection and maximum stress increase with an increase in the supply pressure. The predicted values for the pivots are not fatal when considering the pad's and pivot's mechanical and material design limits. The predicted centerline temperature for the hybrid TPJB at the unloaded pads is slightly higher than that of the hydrodynamic TPJB. At the loaded pads, hybrid TPJB has a higher temperature than the hydrodynamic TPJB until the trailing edge of the recess of pad 3, after which it becomes lower owing to the influence of externally pressurized sCO\({}_{2}\). The result shows that the freshly supplied sCO\({}_{2}\) cools the hybrid TPJB effectively, particularly in the loaded region. Figure 10 shows the centerline (a) density and (b) viscosity of an sCO\({}_{2}\) film flow versus the circumferential coordinate for different supply pressures. As expected, the density increases significantly with an increase in supply pressure following the trends of the centerline pressure in Figure 9b.