C O M P R E S S I B L E F L O W GENERAL INSTRUCTIONS The compressible flow program is designed to operate under MSDOS and will work with all IBM and Compatible PC's. The files on the disk called COMPFLOW.EXE, SONIC.INP, and SONIC.PIC work together, and should be transferred to the same sub-directory of your Hard Disk. They are all part of the program. The .PIC file contains the screens used by the program, and the .INP file contains information for the screen generator. The .EXE file contains the program logic. The other files on the disk with the extension .CFD are example programs. When you save a file it will be saved with this extension. The program is not copy protected, and can be installed onto your hard disk in the normal manner by copying all the files onto a sub directory of the hard disk. The program can be started by inserting the program disk into the A drive and giving the name of the program COMPFLOW. The title screen will come up and you will be asked if you wish to load an existing file or run a new problem. Input L to load a file or R to run a new case. If you select L then the problems saved on the disk will be shown on the screen. You can pick one by moving the cursor to the desired file and pressing the return key. The file will be loaded and the Main operating screen will come up, that shows the results of the adiabatic flow for the saved case. If you pressed R then two screens will come on to permit you to enter the information for the gas properties and pipe. The COMPRESSIBLE FLOW program uses function keys with a command line prompt, and input windows. The system is very user friendly and you will probably not require the use of these instructions to use the program. PROGRAM OPERATION The required data for the gas properties and a description of the pipe must be entered. From the compressible flow results screen, this information can be entered by pressing the F-10 key to input a new case. The F-1 key will rerun the program with new gas properties and the same pipe description. The F-2 key will rerun the problem with a revised pipe description and the same gas properties. GAS PROPERTIES INPUT Input the required information fields, and press the return key after each data entry. You can simply press the return key to accept the data suggesting by the computer. You can move between the data input fields by the use of the up or down arrows on your key board. After all the data is entered the F-10 key is pressed to run the program. The first field is the title for the problem. You can use this field to identify the line by filling in the line number or case description. The other data that must be filled in are the gas flow rate in Lb/H, molecular weight, viscosity, compressibility factor, K ratio or Cp/Cv, and the temperature and pressure of the source. The program assumes these inlet conditions correspond to a stagnant gas volume, such as within a vessel. PIPE DATA SCREEN The pipe schedule can be selected by pressing the F2 key. The default schedule is Schedule 40 CS. If you press the F2 key a window will come up giving other choices. The schedule key allows you to automatically give the true internal diameter and pipe roughness for different standard pipes. These values can be over ridden by the main input screen if non- standard pipe is being used. Input the Nominal diameter in inches and the internal diameter and pipe roughness are calculated and is shown on the screen. The program will go to these fields so that you can override the values, if desired. To accept the computer generated values; press the return key. The Arrow keys that control the cursor will also move the cursor to various fields to permit selected input on desired fields. However, the return key must be pressed to input a new value. The straight length and equivalent length for fittings must be included. The F-2 key will bring up a fittings menu to develop the L/D ratios and equivalent feet for the fittings. When all data is filled in, the program can be run by pressing the F10 key. If you do not press the F10 key then the input cursor will return to the first input field. The following options are available from the command line of the main output screen by pressing the function keys. F-1 Allows the gas input to be altered F-2 Allows the pipe information to be altered F-3 Will calculate the pressure drop of the pipe using the gas properties at the source inlet. This is an incompressible flow solution. F-4 Allows the flow rate of gas to be calculated through the given pipe to meet a specified outlet pressure. The outlet pressure specified must be higher than the critical minimum or sonic pressure at the outlet. F-5 Will size the pipe diameter to meet a specified pressure drop in PSI/100 ft. standard pipe sizes are used up to 2 ft diameter. F-6 Will allow the type of pipe to be changed to rectangular ducts or Annulus. F-7 Not Used F-8 key will save the problem to disk for future work. Press F8 and then F1 to save the file or F2 to load a new file from the disk. The program will prompt you through the disk operations from the command line. When saving a file you should give an eight letter name, but do not include a period or extension. The extension CPF is automatically added to the name by the program for data files. F-9 Will print the problem results. First press the F-9 key and then press the return key when the printer is ready. This can be aborted by pressing the ESC key. F-10 Will erase the present problem and allow you to input a new case. Press the ALT key and the Q key to quit the program. The command line will ask if you really want to quit. Answer with the Y key to exit. RESULTS SCREEN The results screen gives the results of the compressible flow problem for Isothermal and Adiabatic Flow. The screen gives the internal diameter and total length of the pipe plus the equivalent length of the fittings. The Flow of the gas is given. The temperature at the inlet of the pipe is given, as well as at the outlet. The temperature at the inlet for the adiabatic flow case is lower than the source temperature given on the gas input screen because it is adjusted for the isentropic effects of the gas entering the pipe and accelerating to the pipe inlet velocity. The outlet temperature of the gas for adiabatic flow is also reduced for the energy lost to friction. The density at the inlet and outlet conditions is given. The velocity and Mach numbers are calculated for the inlet an outlet conditions. The Mach number is the velocity of the gas divided by the speed of sound of the gas. The Nre Reynold's number and friction factor used by the program is given. The Source pressure, the Inlet Pressure allowing for the enterance effects, and the outlet pressure are given. The critical pressure is given. This is the pressure corresponding to a Mach number of 1 for adiabatic flow and to the point where the Mach number is equal to 1 / SQRT ( K ) for isothermal flow. The critical temperature and density corresponding to the above Mach number limits are given. The Maximum length of pipe of the specified diameter is given This is the length of pipe corresponding to the sonic limitation for the gas. The equations and methods used in this program are describe in the Methods section. Alchemy Systems is interested in your comments regarding the use of this program and future enhancements that may be desired.