Let node I be the outflow from the pipe network and use all other nodes A-H as inflow locations; so flow is from node A through pipes 1, 2, 5, 7, 6, 8, 11, and 12 and out node I. Website: — Pipe Network Analysis — Hardy Cross Method. Applications of Pipe Networks The pipe network analsyis calculation has many applications. A correction to these assumed flows is then computed successively for each pipe loop in the network, until the correction is reduced to an acceptable magnitude. After 5000 iterations a few seconds of real time , the program will stop running and give you this error message, so you can check your input and enter more realistic numbers. Enter the diameters and lengths of these pipes and the desired inflows at nodes A-H.
Analysis of Water Supply Distribution Networks Dr. The raw or treated water is analyzed by testing their physical, chemical and bacteriological characteristics: Physical Characteristics: Turbidity; Color;Taste and odor; andTemperature Chemical Characteristics: pH;Acidity;Alkalinity; Hardness; Chlorides; Sulphates; Iron; Nitrate, and Dissolved solids. Water demand is highly variable, whereas supply is normally constant. Check that you have positive flow into the pipe network. Individual pipe diameters in the pipe network cannot exceed 10 6 m. All pipes must have the same roughness. Free-flow conduits canals, aqueducts and tunnels are preferred in hilly areas or in areas where the required slope of the conduit more or less coincides with the slope of the terrain.
Bacteriological Characteristics: Bacterial examination i. Retain sign from step a and compute sum for loop Σ hf. Allocate these moments thus calculated. You can use your right and left arrow keys to scroll to the left and right to see the velocity in each pipe. The dead-end system shown in Figure 2 is avoided in new construction and can often be corrected in existing systems by proper looping.
Introduction Perfect structural breakdown of large unbreakable concrete building structures in the 1950s was a difficult mission, but we need to pay tribute to the engineering profession as well as to Hardy Cross, for very few failures. You agree that you bear sole responsibility for your own decisions to download or use any of the software listed. The guess doesn't have to be good, but a good guess will reduce the time it takes to find the solution. Despite the development of more efficient computer algorithms, the Hardy Cross method remains as the pipe network analysis method taught to most engineers. The Hardy Cross method is an adaptation of the , which was also developed by Hardy Cross as a way to determine the moments in indeterminate structures.
Total flow into pipe network must equal total flow out of pipe network. An example pipe flow network The Hardy Cross method is an for determining the flow in pipe network systems where the inputs and outputs are known, but the flow inside the network is unknown. Enter one pressure in the pipe network and all other pressures are computed. If you are designing a pipe network as opposed to analyzing a pipe network that is already in place , vary the pipe diameters until the pipe velocities are reasonable and pressure at node D is as low as possible to minimize the height of the water tower. The values that make up k and the value of n change depending on the relation used to determine head loss. The change in flow is applied across the loops. At each junction these flows must satisfy the continuity criterion, i.
Enter the elevations of all nodes. Equations and Methodology for Pipe Networks The pipe network analysis calculation uses the steady state energy equation, Darcy Weisbach or Hazen Williams friction losses, and the Hardy Cross method to determine the flow rate in each pipe, loss in each pipe, and node pressures in the network. Under a some conditions, the water in dead-end lines develops tastes and odors from stagnation. Use the drop-down menu to select the node that you expect will have the lowest pressure in the pipe network - possibly the node furthest from D or the one at the highest elevation; we'll use node I. Adopt a starting solution Q1, Q2, Q3. Support for Darcy-Weisbach and Hazen Williams friction methods is offered.
The flow rate in each pipe is adjusted iteratively until all equations are satisfied. Apart from this, the formulated method in figuring out undetermined binds was unwieldy, since it required as many simultaneous equations to be solved as there were redundancies in the structure. Consider the example of a simple pipe flow network shown at the right. References for Pipe Networks Cross, Hardy. If the method is followed correctly, the proper flow in each pipe can still be found if small mathematical errors are consistently made in the process.
Parallel feeder mains are cross connected at intervals of one to two kilometers, with valves to permit isolation of sections in case of a main break. In the 1930s the Hardy Cross method provided a breakthrough in pipe network analysis. The computed value will give the actual moment at the end. The introduction of the Hardy Cross method for analyzing pipe flow networks revolutionized design. Enter the water withdrawals at all the nodes as negative numbers, then enter the inflow to the pipe network from the water tower at node D as a positive number equal to the sum of the withdrawals from the other nodes.
Please contact us for consulting or other questions about pipe networks. Consequently, if a pipe break occurs substantial portion of the community may be without water. However, this is only an approximation due to the terms that were ignored from the. The method was first published in November 1936 by its namesake, , a structural engineering professor at the. The widely used method of pipe network analysis is the Hardy-Cross method. University of Illinois Bulletin No.