Pipe Gas-Flow Computer Program

By Joe Honeywell

This document is intended to assist engineers in the use of the *Pipe Gas-Flow* computer program. The computer-based program utilizes the Microsoft’s Excel spreadsheet program and contains embedded macros that quickly solve basic gas-flow hydraulic problems with a minimum of set-up time. This user’s Guide will explain the required input parameters, output parameters and the methods used to solve basic gas-flow hydraulic problems. It will also describe the program limitations and error checking capabilities. Example problems are given in both USC and SI units and are intended to help users understand how the computer program can be used to find solutions to everyday engineering problems.

This computer program was prepared with two purposes in mind. The first was to help engineers who are new to the field of fluid hydraulics learn basic fundamental topics without having to solve problems using tedious and repetitive hand calculations. Nothing hinders the learning experience more than consuming time writing down equations, gathering data and organizing the solution only to get the wrong answer because of a simple arithmetic error. Even more frustrating is the correct answer may not be known until the procedure is checked or verified by others. The other purpose of this computer program is to assist engineers with simple solutions to real-world gas flow problems commonly found in everyday job assignments. While this computer program may not be capable of solving all gas flow problems, it can handle the vast majority. It is especially well suited to those problems that require minimal input data or require repetitive calculations to solve.

The *Pipe Gas-Flow* computer program is easy to use and provides quick solutions to common engineering fluid flow hydraulic problems. Users of Microsoft’s Excel program will find it easy to install. Those with a basic knowledge of hydraulics will quickly adapt to the input data requirements and find how easy it is to modify the data for alternate solutions. Users will also find the results easy to understand. The computer program utilizes two Excel worksheets to display input parameters, output parameters, command buttons and warning messages. The two worksheets are **Menu** and **Gas-Flow**, which are described below.

Solutions to gas flow hydraulics are based on a variety of assumptions used to solve any given problem. For this reason the gas handling industry has evolved with many equations used to solve practical problems. The five most common have been included in the computer program. Each has limitations and a practical range of solutions. It is important to note that the equations will give an answer but it is up to the user to select the equation best suited for a particular application. The *Pipe Gas-Flow* program allows the user to select any one of the five equations.

The *Pipe Gas-Flow* program has been prepared to assist engineers with the most common types of gas hydraulic problems. Typically this involves finding one of three primary output parameters, based on knowing the other two parameters. The three primary output parameters are the following:

1. Flow rate 2. Inlet pressure 3. Outlet pressure

If any two parameters are known or assumed, the third can be determined from any one of the five gas-flow equations. The Pipe Gas-Flow program allows the user to select the desired primary output parameter.

The **Menu** worksheet lists notes that briefly describe the program’s basis of flow and pressure calculations, input and output parameters, formulas used to determine the results and in units of measure. See the attachments section for an illustration of the **Menu** worksheet.

SI Gas Flow Worksheet USC Gas Flow Worksheet

The three options for primary output parameters are 1. Flow rate. 2. Input pressure. 3. Output pressure. Any two of these parameters are used to obtain the third. The user can select any one of the three and the other two are designated as input parameters. The user can select the desired primary out parameter by pressing one of the following command buttons.

For example:

The **Menu** worksheet will display the primary output parameter selected.

The **Menu** worksheet allows the user to select one of the five desired gas flow formulas used to calculate the primary parameters. The user can select the desired flow formula by pressing one of the following command buttons.

For example:

The **Menu** worksheet will display the gas flow formula selected.

The worksheet is also used to select the units of measure. The two options for units of measure are as follows:

1. United States Customary (USC) 2. Systeme Internationale (SI)

The user can select the desired units by pressing one of the following command buttons.

For example:

The **Menu** worksheet will display either USC or SI as the selected units.

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