Pipe network calculations

PIPES DATA - Create/Edit pipe

Pipe id (P id)

Connecting node one (N 1)

Connecting node two (N 2)

Constant pressure at 0 node (p[N=0])

Fluid density (ρ)

Pipe length (L)

Pipe internal diameter (d)

Pipe surface roughness (kr)

Local resistance (K)

Dynamic viscosity (μ)

Add pipe Edit pipe

NETWORK DATA

List of pipes

ID	N1		N2	p[N=0] [bar]	L [m]	D [mm]	kr [mm]	K	q [l/min]	v [m/s]
No records found.

List of nodes

Id	q [l/min]	p [bar]
No records found.

QUICK START - Solved pipe network examples

Explanation of network characteristics

Number of pipes: 8
Number of nodes: 5

Pipe network is connected in three points to reservoirs with constant pressure. Those three nodes are marked with number 0. Pressures in those three nodes are 2.2 bar, 2.0 bar and 1.8 bar.

Pipe network has two outflow points at nodes 2 and 4. Flows from the network in those two points are 30 l/min and 10 l/min.

This calculation is based on the calculation of pressures in nodes. To initiate calculation, calculator requires to enter some assumptions of the pressure in nodes. I have used values between highest and lowest pressures in points with constant pressure (from 1.95 to 1.91 bar). This is only rough estimate and actual values will be calculated during calculation process.

Download pipe network sketch in .docx format and create your network drawing in a minute.

Example 3 - download sketch in .docx

Download detailed instructions - how to use the calculator

Download Pipe Network Calculator Instructions - last revision 26th Dec. 2021.
Method of nodes explained and implemented in the online calculator.

Short instructions for creating a network

For the calculation of the pipe network, it is necessary to enter the characteristics of the network which consist of pipes and nodes.

Note: In order to make easier the entry of data on the pipe network, I suggest that you first draw a sketch of the pipe network and mark all the pipes and nodes.

Pipes

For each pipe, it is necessary to enter its ID (integer greater than 0), inner diameter, length, and the roughness of the inner surface. It is also necessary to specify the ID numbers of two nodes that this pipe connects for each pipe. Actual flow direction from one node to another will be calculated and presented after calculation in terms of the arrow pointing from one node ID to another.

Nodes

Nodes are points where two or more pipes join. If the system contains a tank or pump, such places are defined as nodes.

There are two types of nodes.

Fixed pressure nodes - reservoirs and pumps

The first type are nodes where the pressure is constant and in such nodes, the pressure is not calculated - they are e.g. tanks or pumps. For pumps, it is necessary to insert two nodes with constant pressure in front of and behind the pump, and not to insert a pipe between those two nodes. All nodes of this type must be numbered with ID = 0. It is normal to have multiple nodes with ID=0 - like in the system with two or more reservoirs and pumps. This group of nodes are not required to be entered in the table “List of nodes”. Nodes with ID=0 are not possible to enter in the list.

Calculated pressure in nodes - where pipes connect

The second type is nodes in which two or more pipes connect and in which the pressure is the subject of calculation. Optionally, from this type of node, the volume of the flow that flows out of the node can be specified, and this volume is considered constant in the calculation. Normally, the amount of fluid that flows into the node and that flows out of that node is the same. All nodes of the second group must be numbered with an integer greater than 0 (1,2,3,4…).

This group of nodes are required to be entered in the table “List of nodes”.

For all nodes of the second group, it is necessary to enter the assumed pressure values in the node itself. These are the initial values, and the actual values will be displayed after the calculation. It is correct to enter the pressure values that are between the pressures set in the nodes of the first group. For example, if the pipe network between the tank with a constant pressure of 2 bar and the pipe is open to the atmosphere with an overpressure of 0 bar, then it can be assumed that in the nodes in the pipe network the pressures will be from 1.9 bar to 0.1 bar moving from the tank to the pipe that is open atmosphere.