2.2.2. Sizing of the Inlet Section

For this section, the parameters determined are as follows:


$$\frac{d\_{1p}}{d\_2} = -0.00003n\_s^2 + 0.0106n\_s + 0.1219\tag{32}$$


$$d\_{1m} = kd\_{shf} \tag{33}$$

The coefficient *k*, based on the measurements obtained on the range of pumps available (Figure 5), is set equal to 1.65.

**Figure 5.** Statistical distribution of the ratio *d1m*/*dshf*.


$$\begin{array}{c} \begin{array}{c} \begin{array}{c} \beta\_{1p\,\,t\,lall} \\ \end{array} \\ \begin{array}{c} \begin{array}{c} \\ \end{array} \\ A\_{1r} = \,\,b\_{1} \left( \pi \,d\_{1} - \frac{z \,t\_{1}}{\sin \beta\_{1p}} \right) \\\\ \end{array} \\ \begin{array}{c} \begin{array}{c} \big{ } \\ c\_{m1} = \,\eta\_{v} \, \, \frac{Q}{A\_{1r}} \end{array} \\ \end{array} \\ \begin{array}{c} \begin{array}{c} \beta\_{1p} = \,\, \tan^{-1} \left( \frac{c\_{m1}}{u\_{1}} \right) \end{array} \end{array} \end{array} \end{array} \tag{34}$$


$$b\_1 = \frac{d\_{1p} - d\_{1m}}{2} \frac{1}{\cos(\theta)}\tag{35}$$

An average value of the angle *θ* was obtained from a series of measurements carried out on the pump subjects of this analysis, and it is equal to 40◦.
