Mechanical Operations For spheres, the surface shape factor is given by (where, A = area, V = volume, and D = diameter) π(=A/D²) None of these π/6(=V/D³) AD/V π(=A/D²) None of these π/6(=V/D³) AD/V ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations For a turbine agitated and baffled tank, operating at low Reynold's number (based on impeller diameter), the power number (Np) varies with NRe as Np ∝ NRe Np → constant Np ∝ 1/NRe Np ∝ √NRe Np ∝ NRe Np → constant Np ∝ 1/NRe Np ∝ √NRe ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations The specific cake resistance for incompressible sludges is (where ΔP = pressure drop over cake) ∝ √ΔP ∝ ΔP Independent of ΔP ∝ 1/ ΔP ∝ √ΔP ∝ ΔP Independent of ΔP ∝ 1/ ΔP ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) D 0.5 D 2 D 1.5 D D 0.5 D 2 D 1.5 D ANSWER DOWNLOAD EXAMIANS APP
Mechanical Operations The critical speed of a trommel (N) is related to its dia (D) as N ∝ √D N ∝ 1/D N ∝ 1/√D N ∝ D N ∝ √D N ∝ 1/D N ∝ 1/√D N ∝ D ANSWER DOWNLOAD EXAMIANS APP
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