1. Background and Objective
the pumping system is having all six pump working. All pumps are of CVP 1450.
the discharge line is connected to siphon making and breaking arrangement.
The system is connected through common header to collect the total dis charge.
However, during power failure, due to breaking of the siphon, each pipeline will be acting as individual system. Thus we have considered one system for the analysis.
All the sections of the ducts are converted to equivalent pipe diameters. Objective of this analysis is to study the system for surge conditions and suggest suitable protection devices to control the surge in the system.
2. System description and data
The pump house line is made up of concrete material with difference rectangular cross section. The rectangular sections are converted to equivalent pipe diameter as a input to software. The transmission line is then connected to open delivery reservoir.
3. Consideration of surge or hydraulic transients
3.1 Causes of transients
hydraulic transient or surge is a phenomenon occurring in closed conduit or pipe flows, associated with rapid changes in discharge in the pipe. The rapid change in discharge and the associated velocity is accompanied by a change in pressure, which is propagated at acoustic speed, which varies with material and wall thickness of the pipe. Like any other Phenomenon, the wave is transmitted and reflected at difference boundaries such as reservoir or pump. It is also damped friction it propagates. In pumping system, changes in discharge may be caused by valve closure or opening.
The planned stopping and starting of a pump is also associated with valve opening or closing. In general, in pumping main carrying water, valve operations need not be very rapid and hence surge pressure due to valve operations and planned starting or stoping of a pump can be kept under control. Surge pressure due to starting cannot exceed shutoff head of the pump (unless a valve at the downstream end is closed).
Power failure and single pump failure from the most critical surge condition in a pumping main. Power failure critical with regard to surge pressure in the main transmission main, while single pump failure is critical with regard to surge pressure in the pump house.
In this system the non return valve is not as apart of the system, up on power failure siphon system breaks and the water in vertical column flows back to the sump and avoiding the surge in the system. During starting of the pump we need to fill the pipe and siphon to ensure proper operation of the pump system.