Flow in Pipe Networks
Pipeline Systems
A pipeline system can range from a single pipe to a very large and complex network with hundreds of interconnecting pipes. It may be as simple as a pipe carrying water from one reservoir to another reservoir, or it may be more complex with many pipelines interconnecting to distribute fluid over a large area, or it could fall somewhere in-between such as a system that transfers a chemical from a supply container to various process points.
Hydraulic Design of Pipe Networks
Pipe networks are special class of problem in Hydraulic Design. An engineer may have one or more sources of fluid (reservoirs or tanks) and their brief may be to transfer this liquid to one or more destinations, with each outlet receiving a required amount of flow.
The pipe work may already exist and the engineer may just need to size and choose an appropriate pump that will meet the requirement. Alternately this may be a new installation and the engineer may be required to size and specify the pipe sizes and pipe materials that will be used. For heating and cooling systems the pipe network may contain a number of closed loops where the fluid is re-circulated around the system.
In all of these systems it is critical that the engineer understands how the pipelines, pumps, fittings, components and controls interact. The first step is normally to solve the pipe network for the steady state condition, to find the flow in each pipe and the pressure at each node of the network, together with the operating point of any pumps in the system.
Flow and Pressure Calculations
Calculating the flow and pressure throughout a pipe network is a complicated task. It requires a detailed understanding of the mathematical equations that are used to calculate head losses and friction losses that occur when fluid moves through a pipe and when multiple pipes are involved the problem becomes much harder, as the flow and pressures at each point have to be balanced.
Even a very competent engineer would require hours (sometimes days) of hand calculations to accurately solve even a relatively small network of pipes. The use of a complicated spreadsheet solver may help them with systems that only contain a few pipes but in todays modern world the only real solution to this problem is to use a sophisticated computer software program that can model the pipe network completely.
Software that Calculates Flow Rates and Pressure Losses
Using a program such as Pipe Flow Expert allows the engineer to model and solve their pipe system such that they can analyse the flow and pressure in each part of their network.
It means that they can easily see when important design conditions (such as the maximum fluid velocity in a pipe) are not met and with a simple adjustment, they can for example, increase the size of a pipe to reduce a high velocity. With a few clicks of their mouse they can then re-calculate their system to see what effect the change to pipe size has on their system.
Using software that has a robust calculation engine, such as Pipe Flow Expert, also helps to eliminate mistakes that occur when complicated calculations are done by hand.
