## 4 Results and Discussion
### Analysis of Coexistence of Laminar and Turbulent Flow  
Figure 2 shows the changes in the static tilting angle of each pad (in degree) of tilting pad bearing with assembled eccentricity ratio \(\varepsilon^{\prime}\) at a rotating speed of 18,000 r/min. With the increase of \(\varepsilon^{\prime}\), the tilting angle of both the 5# pad and the 4# loaded pad increases, and that of the 2# pad and 3# loaded pad decreases. The results obtained by the model considering turbulence and the pure laminar model were compared. The corresponding distributions of the local Reynolds number of each pad are shown in Figure 3. The larger the \(\varepsilon^{\prime}\) is, the lower the local Reynolds number \(Re\) of oil film of 3# and 4# loaded pads are, and the higher the \(Re\) of other pads are. The reason is that a larger \(\varepsilon^{\prime}\) makes a closer distance between the shaft and loaded pads, which means a smaller oil film thickness of loaded pads. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Bearing radius (\(R\)) & 70 mm \\ Bearing length (\(L\)) & 56 mm \\ Pad arc angle (\(\alpha\)) & 60\({}^{\circ}\) \\ Preload factor (\(m\)) & 0.5 \\ Pivot offset (\(\gamma\)) & 0.5 \\ Density of lubrication oil (\(\rho\)) & 871 kg/m\({}^{3}\) \\ Average viscosity of oil film (\(\mu_{a}\)) & 9.37 mPa-s \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameters of tilting pad bearing. Figure 2: Changes of the static tilting angle of each pad of tilting pad bearing with assembled eccentricity ratio at different assembled clearance. For \(C_{b}\) = 109.5 \(\upmu\)m, the flow state in all the pads is laminar at \(\epsilon^{\prime}\) = 0.1. When the \(\epsilon^{\prime}\) increases, turbulence appears in the upper reaches of the 1# top pad (see Figure 3a), which makes the tilting angle of the 1# pad larger (see Figure 2a) because the turbulence in the upper reaches increases the oil film force. However, the difference between the tilting angle of the 1# top pad obtained by the model considering turbulence and the pure laminar model increases first and then decreases at \(\epsilon^{\prime}\) beyond 0.5 because the proportion of turbulence zone of the 1# pad becomes larger than pivot offset and the turbulence existed also in pivot downstream. When the \(\epsilon^{\prime}\) increases to 0.7, flow in the whole oil film of the 1# pad is turbulent, so the influence of turbulence on its tilting angle becomes weak. The flow state in the 3# and 4# loaded pads is laminar at arbitrary \(\epsilon^{\prime}\) for \(C_{b}\) = 109.5 \(\upmu\)m. The tilting angle of both the 2# and the 5# pad obtained by the model considering turbulence becomes larger than that by the pure laminar model when \(\epsilon^{\prime}\) is over 0.6 because turbulence appears in the upper reaches of the oil film of 2# and 5# pad. The relation between the tilting angle of the five pads for \(C_{b}\) = 143.5 \(\upmu\)m has some difference to smaller assembled radius clearance when the coexistence of laminar and turbulent flow is considered. The turbulence in the 2# pad makes its static tilting angle close to that of the 3# pad. The proportion of turbulence zone of the upper reaches of both the 2# and the 5# pad is about equal to pivot offset at arbitrary \(\epsilon^{\prime}\) (see Figure 3b), so the turbulence effect increases their tilting angle obviously (see Figure 2b). The flow state in all the pads contains laminar and turbulence together at \(\epsilon^{\prime}\) = 0.1, 0.2, and 0.3. When the \(\epsilon^{\prime}\) increases to 0.4, the flow state in the 3# and 4# loaded pads become pure laminar flow. The influence of turbulence on the tilting angle of the 3# and 4# pads is also not very obvious at small \(\epsilon^{\prime}\) because their lubricating film is thin. The turbulence exists in the 1#, 2#, and 5# pads at arbitrary \(\epsilon^{\prime}\).