For a fixed-diameter impeller, if pump speed increases by factor n (N₂/N₁), the shaft power approximately scales with what exponent on n in ideal affinity?
Choices
- (A) n³ (power ∝ N³, flow ∝ N, head ∝ N²)
- (B) n²
- (C) n
- (D) 1/n
Correct answer: (A)
n³ (power ∝ N³, flow ∝ N, head ∝ N²)
Explanation
Affinity laws: Q₂/Q₁ = n, H₂/H₁ = n², P₂/P₁ = n³.