Based on the theoretical studies carried out in the previous chapters, particularly in Chap. 3 , this chapter seeks to obtain a first approximation of the geometric physical limits of the real hydraulic flow path (RHFP) for the BMHIT to delimit the space occupied by the water flow as a real fluid, between the turbine inlet and outlet. This space comprises the physical limits of the injector, the director vane, the rotor, and the housing. Therefore, we will carry out a study on our preliminary needs, i.e., data, the limitations, and the results, particularly on the operational field, and the limits of the maximum hydrodynamic forces to which each component is submitted. This will allow us to establish an algorithm for preliminarily calculating the hydrodynamics of a BMHIT, and in the next chapter, to make the respective mechanical calculations.