In the given below figure of Mechanism of vacuum generation, point ‘2’ is the indication of _____(a) Poynting point(b) Vena contracta(c) Stack point(d) Steric pointThe question was asked in unit test.Question is from Aspiration Effect topic in division Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

In the given below figure of Mechanism of vacuum generation, point ‘

1.	In the given below figure of Mechanism of vacuum generation, point ‘2’ is the indication of _____(a) Poynting point(b) Vena contracta(c) Stack point(d) Steric pointThe question was asked in unit test.Question is from Aspiration Effect topic in division Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I
Answer» Correct answer is (b) Vena contracta For explanation I WOULD say: The constricted region at point 2 in the figure is known as vena contracta. A sudden CHANGE in the flow direction cause the aspiration effect and thus VACUUM as the liquid METAL stream contracts around a sharp CORNER due to the momentum effect. To avoid vacuum, the mould is made to fit the vena contracta.

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