ENERGETICAL AND CAVITATIONAL ANALYSIS OF A NETWORK PROFILES IN LIQUID MEDIUM

摘要

The work describe energetic and cavitational behavior of a network profiles (NACA 8410, NACA 0010). The first part of this work partially restores the theoretical and calculation background, which was detailed in the cited paper. Starting from 3D surfaces created for C_(pmin) (β_(IN) β_S), C_L (β_(IN), β_S), C_D (β_(IN) β_S), at t/L =const., lines of equal value can be built. For C_(pmin) as example, these representations allow fast and reliable determination of dangerous cavitational regimes of the network. The curves C_(Ftang)> 0, C_(Ftang)< 0, were built in the same manner, in different frames and that may give an insight into the operating field in which significant forces occur from active torque composition. The analysis took into consideration the classical curves for a plane network profiles having a constant stagger angle β_S = const. and as parameter ratio t / L = 0.5, 0.75, 1.00, 1.25 or at constant ratio t / L = constant having as parameter the stagger angle β_S = 30°, 60°, 90°, 120°. Finally, the calculations and representation were oriented towards design so there were built curves of equal value for C_(Ftang), C_(Faxial), C_(pmin) in the field δ_U - β_(IN), as well as synthetic images valuable for the designers of axial hydraulic machines, as they explicitly indicate the areas recommended for the naval machine's operating system, or the avoidable ones.