Method for calculating characteristic curve of centrifugal fluid machine by computer

摘要

A computer-implemented method of calculating various types of characteristic curves of a centrifugal fluid machine according to the present invention can easily calculate a Q-H characteristic curve, a Q-E characteristic curve, a Q-NPSH characteristic curve, or the like. The method of calculating various types of characteristic curves uses two prescribed characteristic curves Y1=a₁₁+a₁₂x+a₁₃x²+ . . . +a_1nx^(n−1) and Y2=a₂₁+a₂₂x+a₂₃x²+ . . . +a_2nx^(n−1) formed of high-order equations for a centrifugal fluid machine to calculate a characteristic curve Y3=b₁+b₂x+b₃x²+ . . . +b_nx^(n−1) formed of a high-order equation which passes through different coordinates (x₃, y₃). The method of calculating various types of characteristic curves selects prescribed coordinates (x₁, y₁) on the characteristic curve Y1 and corresponding prescribed coordinates (x₂, y₂) on the characteristic curve Y2, and calculates and outputs a characteristic curve Y3=b₁+b₂x+b₃x²+ . . . +b_nx^(n−1) formed of a high-order equation which passes through different coordinates (x₃, y₃), with use of an equation b_n={a_1nkh₁(1/kq₁)^(n−1)×(y₃−y₂)/(y₁−y₂)}+{a_2nkh₂(1/kq₂)^(n−1)×(y₁−y₃)/(y₁−y₂)}.