| 摘要 |
A method for calculating one of the characteristic curves of a centrifugal fluid machine, such as a Q-H characteristic curve, a Q-E characteristic curve, and a Q-NPSH characteristic curve by using a computer. By the method, a characteristic curve Y3 passing another point (x3, y3) and expressed by a high-degree expression Y3-=b1+b2x+b3x<2>+...+bnx<(n-1)> is defined by using two desired characteristic curves Y1, Y2 of a centrifugal fluid machine expressed by high-degree expressions Y1=a11+a12x+a13x<2>+...+a1nx<(n-1)> and Y2=a21+a22x+a23x<2>+...+a2nx<(n-1)>. The point (x3, y3) is not on the two characteristic curves Y1, Y2. By the method, the characteristic curve Y3 is defined using an expression bn={a1nkh1(1/kq1)<(n-1)>x(y3-y2)/(y1-y2)}+{a2nkh2(1/kq2)<(n-1)>x(y1-y3)/(y1-y2)} by selecting a predetermined point (x1, y1) on the characteristic curve Y1 and a predetermined point (x2, y2) on the characteristic curve Y2 corresponding to the point (x1, y1).
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