Q.
The rate of flow of glycerine of density 1.25×103kgm−3 through the conical section of a pipe if the radii of its ends are 0.1m and 0.04m and the pressure drop across its length 10Nm−2 is
From Bernoullis theorem p1+21ρv12=p2+α1ρv22 ∴p1−p2=21ρ(v22−v12) ∴10=21×1.25×103(v22−v12) ∴v22−v12=1.25×10310×2 =16×10−3 ...(i)
Also from equation of continuity =A1v1=A2v2 πr12v1=πr22v2 ∴v2v1=[r1r2]2=0.10.04=0.4 v1=0.4v2 ... (ii)
Substituting this value in Eq. (i) v22−(0.4v2)2=16×10−3 v2=1.38×10−1=0.138ms−1
Rate of flow of glycrine v=A2v2 =πr22v2 =6.93×10−4m3s−1