Print this page Hydraulic Calculations Using Mathcad - Part 1: Simple Pipelines
D.M. Griffin, Jr.,P.E., Ph.D., D.WRE
Course Outline
This course illustrates the benefits of using Mathcad to carry out hydraulic calculations required to determine the pressure in a pipeline of known diameter when the Darcy Weisbach (D-W) friction factor is not known. Mathcad is a software application that is used worldwide for doing engineering calculations. Once the learning curve is mastered it can save valuable time and effort in carrying out a wide variety of engineering calculations while reducing a variety of common errors, thus making it a valuable tool in the engineering profession.
This course includes
a multiple-choice quiz at the end, which is designed to enhance the understanding
of the course materials.
Learning Objective
At the conclusion of this course the student should be able to:
- Determine the diameter of a pipeline required to carry a specified flow rate using the equation solving tools in Mathcad;
- Understand how the use of Mathcad can dramatically reduce the time, effort, and expense required to solve such problems; and
- Understand the benefits of using Mathcad for doing engineering calculations as
compared to other software applications such as Excel.
Intended
Audience
This course is intended for civil, environmental, and mechanical engineers as well as anyone doing or interested in doing pipeline calculations using Mathcad. It is also beneficial for those just wanting to learn how to use Mathcad.
Benefits to Attendee
The attendee to this will be able to employ Mathcad to solve simple pipeline problems efficiently and in such a way as to allow for changes in the various parameters of the problem (diameter, pipe length, pipe material, liquid temperature and viscosity) quickly in order to understand how such changes affect the problem solution.
Course Introduction
This entire document (text and mathematics) was produced using Mathcad. Note that even though you may be unfamiliar with Mathcad you will be able to read, follow and understand this course material. This is, in the author's opinion, the primary benefit of using Mathcad compared to other software applications. Mathcad documents, properly prepared can be understood by anyone, even if they have never used it.
Course Content
The course content is in the following PDF file:
Hydraulic Calculations Using Mathcad - Part 1: Simple Pipelines
Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader.
Course Summary
We have solved a pipe flow problem that required three equations to obtain three unknowns. Unlike most solution techniques which are manual in nature and require a tedious, time consuming, and error prone recursive procedure we used a Mathcad solve block. The characteristics of this solution which make it far more desirable that either a manual solution or an Excel solution are listed below:
1. Mathcad handles a wide variety of units in several different unit systems and enforces
dimensional consistency at all times. In this example all known values were entered with
units. The units only need be correct, Mathcad handles all unit conversions thus
eliminating potential errors. Mathcad has a large number of "known" units and unit
systems. To see the possible unit systems click Tools =====> Worksheet options
======> Unit System. To see the available units in Mathcad click on Insert =======> Unit
2. To the maximum extent possible variable names are used rather than numerical values, in this way problem parameters only need to be changed in a single location. For example changing the value of the equivalent roughness from .00085 ft for cast iron pipe to 0.00005 ft for PVC pipe at a single location in the file results in a new solution with the pressure at point 2 equal to 70.03 psi. Thus, it is it easy to explore a wide range of values of problem parameters using minimal time, cost, and effort. This is why Mathcad appeals to consulting firms as well as other entities faced with making a profit.
3. This document, with the exception of the schematic, has been written entirely in Mathcad, and is being distributed as a PDF document. However, it can (hopefully) be understood by someone with no prior knowledge of Mathcad. The schematic was drawn using Visio, a low end CAD package that is now a part of Microsoft Office. The drawing was copied and pasted into Mathcad as a device independent bitmap (DIP).
AND FINALLY, A CAUTIONARY NOTE
Mathcad cannot protect the user from incorrect equations, too many equations, too few equations, or equations that are not independent. In such situations it may very well return a solution that is incorrect. While Mathcad can reduce the labor required to obtain a solution it is not a substitute for the basic knowledge needed to solve the problem in the first place.
Related Links and References
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
