Theory and Design of Axial Flow Fan (Part III)

Abstract

The condition that the axial flow fan is to be operated at maximum efficiency is to make the overall manometric efficiency maximum taking also the loss of pipe line which is connected the fan into consideration. We show a disign to obtain the maximum manometric efficiency, in two cases where the diameter of impeller is determined freely or given, when the discharge, r.p.m., no. of stages and pressure are known or discharge and r.p.m. are given. We also described the design to make power of non-pressure fan for ventilating minimum and prepar diagrams of φ_t, ψ_t, and η_Mb useful for design of axial fan with guide vane (axial inlet flow and axial outlet flow) and fans with guide vanes ahead of and past the impeller when neglecting the pipe resistance. We can obtain the values of size and efficiency of fans for given data at once.