ABSTRACT
The effect of using different protection devices on water hammer phenomenon to provide an
acceptable level of protection against system failure due to pipe collapse or bursting is presented.
Water Hammer and Mass Oscillation (WHAMO) software is used in the analysis which uses the
implicit finite difference scheme for solving the momentum and continuity equations at unsteady
state case. Assiut city water supply network is used. The network is supplied from two points at
pump No. 36 and pump No. 37. Flow of pipe network is studied under steady normal case, without
any protection case against water hammer phenomenon, and the model under different operation
cases; with a transient protection device(s) such as non-return valve, open surge tank, air chamber
and pressure relief valve (PRV). The results are performed for three scenarios; the first is the normal
operation of pump 36 and failure of pump 37, the second is the normal operation of pump 37 and
failure of pump 36, and finally failure of pumps 36 and 37 together. The results showed that using
of open surge tank or air chamber with non-return valve protects the pipe network effectively from
the harm of water hammer. Also, using PRV with non-return valve protects the pipe network from
extreme pressures. Although using non-return valve only doesn’t have a great effect on the
maximum pressure head than the normal case, it protects the network from the more low pressures
than without protection one. All protection cases safeguard the pipe network from the extremes of
water hammer, but increase the water hammer wave period. Finally, the sudden shut down of the
pumps 36 and 37 together has the large effect on the pressure heads than the shut down of any of
them only.