Question 15, morning of the second day, 2016
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According to the book published by the Examination Board, the allowable cavitation margin is calculated as the base value plus an additional 0.3 m; then why is a margin of 0.5 m used in this question? Which one should be taken as the standard? I would appreciate some guidance from those who are more experienced.
OP, could you send me a copy of the 2016 case you have via email? 504226382@qq.com Thank you, OP; you will definitely make it!
15 B Hg = Hs’ – u1²/2g – Zf = 5 – 8 = -3 m; in reality, an additional reduction is needed (a value between 0.3 and 1.0 is acceptable). Here, 0.5 m is taken, so the actual installation height is -3.5 m. Both flow rate and head are independent of density and remain unchanged; therefore, this value can be used.