H
1. Calculate the velocity of propagation of pressure wave in the following cases of flow through pipes:
Cases Liquid Density
(kg/m3) Bulk modulus of elasticity (K) MPa Pipe dia
(mm) Pipe thickness
(mm) Material Modulus of elasticyty (E)
I Water 998 2190 300 8.0 steel 2.1x105
II Water 998 2190 800 10.0 cast,iron 1.0x105
III Water 998 2190 450 // rigid pipe //
IV Sea water 1025 2280 300 // rigid pipe //
V Mercury 13550 25500 10 // rigid pipe //
2. A valve at the downstream end of a 1.20 m diameter steel penstock carrying water is operated suddenly so as to reduce the flow from 3.0m2/s to 0.5 m2/s. Estimate the maximum water hammer pressure rise at the valve if the pipe thickness is (i) 7.5mm (ii) 12mm ( For water : K = 2200 MPa; for steel : E : 2.10x105 MPa)
Cases Liquid Density
(kg/m3) Bulk modulus of elasticity (K) MPa Pipe dia
(mm) Pipe thickness
(mm) Material Modulus of elasticyty (E)
I Water 998 2190 300 8.0 steel 2.1x105
II Water 998 2190 800 10.0 cast,iron 1.0x105
III Water 998 2190 450 // rigid pipe //
IV Sea water 1025 2280 300 // rigid pipe //
V Mercury 13550 25500 10 // rigid pipe //
2. A valve at the downstream end of a 1.20 m diameter steel penstock carrying water is operated suddenly so as to reduce the flow from 3.0m2/s to 0.5 m2/s. Estimate the maximum water hammer pressure rise at the valve if the pipe thickness is (i) 7.5mm (ii) 12mm ( For water : K = 2200 MPa; for steel : E : 2.10x105 MPa)