Surge vessels in Karachi,
PakistanWhenever flows in pipeline systems change,
transient pressures are generated. In extreme cases these transient
pressures (or waterhammer) can rupture pipelines or damage
fittings. In less extreme cases contaminated water or air may be
drawn into the system or the system may be subjected to pressures
for which it was not designed. Other potential problems include
shock loads caused by air expulsion or slamming of check valves,
collapse of thin walled pipes under near vacuum pressures and
thrust block movement.
Measures to alleviate surge include the provision of air vessels,
surge feed tanks, increased pump inertia (flywheels), control
valves, pressure relief valves, air valve attachments, fast acting
check
valves or the selection of a different pipe material.
Mott MacDonald’s surge analysis capability allows consideration of
transient pressures and system operation to be fully integrated
into the overall design process rather than being considered in
isolation. Transient hydraulic problems are often linked with
problems of air management, system operation and control.
Consideration of these issues together at design stage keeps the
design process unified allowing evaluation of a wider range of
options early in the system selection and design process.
Our resources include the commercial software package Flowmaster2
and in-house software. Flowmaster2 is widely used in the water
industry as well as the petroleum, process, aerospace and
automotive industries for all types of transient hydraulic
analyses. It uses the well-established method of characteristics
and is COM enabled. This allows it to be linked to other standard
software and for complex control rules for pumps and valves to be
programmed into the models.
Projects on which we have provided surge analyses or designed surge
protection include the following:
- Dhabeji, NEK and Manghopir Pump Stations, Pakistan
- Barka Water Transmission Project, Oman
- Hyderabad Water Supply Project, India
- Heck Hensal and Pollington, Yorkshire, England
- Cork Main Drainage, Ireland
- North Road PS, Woodburn, Northern Ireland
- River Spey Abstraction Scheme, Scotland
- North Lantau Sewage Main, Hong Kong
- Tees Wiske Transfer Scheme, Yorkshire, England
- Cumwinton Scheme, Cumbria, England
- Thames Water Transmission Projects (4 systems)
- Hong Kong Seawater Cooling Systems (5 systems)
- Shuaiba Recirculation System, Kuwait.
