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H2-O2-F2.DOC ------------ DOCUMENTATION FOR H2O2 (V3.12) AND H2F2 (V1.01) SERIES OF ROCKET ENGINE ANALYSIS PROGRAMS Package Release 1.00 (c) Dec., 1987 Software Package by Kerry Hicks, MS --- ABSTRACT --- H2O2 and H2F2 are interactive computer programs that serve as quick and convenient means to examine the perform- ance of Hydrogen/Oxygen and Hydrogen/Fluorine rocket engines respectively. While originally written to assist the Under- graduate/Master's level astro/aero student in his propulsion courses, the programs are accurate enough to perform "back of the envelope" type calculations. If you are tired of computing such things as Adiabatic Flame Temperature, Frozen Flow Thrust, Equilibrium Flow Thrust, Mass Flow Rate, Combustion Products, and Exit Velocity without having any way to check your answers, then this series of programs is for you. Since the programs are very similar, the remaining documentation will tend to refer only to H2O2. Unless indicated otherwise, H2F2 operates exactly the same. 1 TABLE OF CONTENTS ----------------- Section Page -------- ---- Disclaimer . . . . . . . . . . . . . . . . . . . . . . . 3 Hardware and Software Requirements . . . . . . . . . . . 3 Files . . . . . . . . . . . . . . . . . . . . . . . . . . 3 What is H2O2 (and H2F2)? . . . . . . . . . . . . . . . . 4 Rules for Use . . . . . . . . . . . . . . . . . . . . . . 4 Operation of H2O2 (and H2F2) . . . . . . . . . . . . . . 5 Output . . . . . . . . . . . . . . . . . . . . . . . . . 6 Example from H2O2 . . . . . . . . . . . . . . . . . 7 Example from H2F2 . . . . . . . . . . . . . . . . . 10 Limitations of H2O2 and H2F2 . . . . . . . . . . . . . . 12 Miscellaneous Notes . . . . . . . . . . . . . . . . . . . 13 Update Histories . . . . . . . . . . . . . . . . . . . . 15 H2O2 . . . . . . . . . . . . . . . . . . . . . . . . 15 H2F2 . . . . . . . . . . . . . . . . . . . . . . . . 18 2 --- DISCLAIMER --- These programs are provided "as is" to the Public Domain without warranty of any kind. To the best of my knowledge they are free from errors and completely "safe." Further, ALL of the data used in the writing of these pro- grams is public information and is available in references such as the JANAF Thermochemical Tables and certain NASA publications. Finally, I'm not responsible for ANY loses or damages resulting directly or indirectly from the use, misuse, or inability to use this software. Use of these programs implies agreement. --- HARDWARE AND SOFTWARE REQUIREMENTS --- -- As provided, H2O2 should run on any PC, XT, AT, or true compatible computer. with somewhere around (but less than) 256K. It may or may not work on any other system. -- Most of the displays are in color and may not show up completely on a monochrome system. The program will, however, function correctly. -- A math coprocessor is HIGHLY recommended by isn't required. --- FILES --- The following files should be on the distribution disk: -- READ.ME - Revision history and last minute changes and updates. -- H2O2.BAS - A portion of the source code for H2O2. -- H2O2.EXE - Executable file for MS-DOS computers. If a math coprocessor is present, it is used; if not, it is emulated. -- H2F2.BAS - A portion of the source code for H2F2. 3 -- H2F2.EXE - Executable file for MS-DOS computers. -- H2-O2-F2.DOC - This manual. Due to the size of the complete source code listings, I'm no longer including them in the PD version of this prog- ram. Requests for the source code can be directed to me, Kerry Hicks, on the BBS listed at the end of this document. I reserve the right to refuse any or all requests. --- WHAT IS H2O2? --- H2O2 is a combination of the most useful features from programs I have written for three classes in propulsion. It will predict the most commonly used performance parameters for a wide variety of hydrogen/oxygen rocket engines. These parameters include adiabatic flame temperature, frozen flow thrust, equilibrium flow thrust, mass flow rate, exhaust velocity, mole fractions of combustion products, and mole fractions of the exhaust. It isn't intended to be flashy or omnipotent, just to easily perform the most common calculations for so-called rocket problems. Other programs are available to perform these calculations, but I know of no other PD program written for the home computer that will do all of these calculations with minimal effort on the user's part. (H2F2 computes the same parameters for hydrogen/fluorine rocket engines.) --- RULES FOR USE --- These versions of H2O2 and H2F2 are released to the Public Domain. This means that you are free to copy it and distribute them for noncommercial use to other students, engineers, and instructors IF AND ONLY IF: - ALL of the ORIGINAL files remain intact and are copied onto the same disk. - NO FEE IS CHARGED FOR USE, COPYING, OR DISTRIBUTION with the following exceptions: Clubs, user groups, 4 and Public Brand Software may charge a nominal fee (less than $6.00) for expenses and handling while distributing this package. Instructors are specific- ally FORBIDDEN from charging a fee in excess of the diskette price when distributing any part of this package to their students! Again, use of the program implies agreement to these conditions. --- OPERATION OF H2O2 --- First, read the file "READ.ME" for any last minute changes/modifications to H2O2. Next, bring up H2O2 by running the executable file H2O2.EXE. The program should be self-explanatory. But, the notes in the following paragraphs should be helpful. Unfortunately, many instructors still insist on using a hybrid mixture of English and SI units for rocket problems. To accommodate these people, the program takes input and gives output in the one of the more common hybrid sets. (Note, however, that most internal calculations are per- formed using the more convenient/intelligent metric units.) To avoid confusion, H2O2 lists the units that you should use when it prompts for input. (If your instructor uses other units, then the conversions should be the least of your problems!) For input you must provide: -- An output file. Enter any legal DOS file name or enter "LPT1:" to send the output directly to the printer on most systems. (If your printer is on LPT2, then "LPT2:" will send your output to the printer.) -- A title for your engine (optional). -- Chamber pressure (in atmospheres). -- Nozzle throat area (in square feet). (See note below about computation of only the AFT.) 5 -- Nozzle exit area (in square feet). (See note below for computation of only the AFT.) -- Mass flow ratio of oxygen to hydrogen (dimensionless quantity.) (When running H2F2, you enter a fluorine to hydrogen mass flow ratio.) Note: The Adiabatic Flame Temperature is computed first. This is done for a particular reason -- instructors like to give the relatively simple computation of an AFT as a homework problem before assigning the full-blown thrust calculations. If you only have the pressure and the mass flow rate, enter non-negative values for the nozzle areas and hit "Ctrl-Break" after the AFT has been found. (When the message on the screen indicates that the program has begun working on Equilibrium Flow Calculations, the AFT has been found and printed to the output file and the program can be aborted.) Thus, H2O2 handles the computations involving just the combustion chamber without any knowledge about the nozzle! (Note: For thrust calculations, you should let the program run until finished.) --- OUTPUT --- The output generated by H2O2 for a one variation of the Space Shuttle Main Engine is shown on the next few pages as an example of the output you can expect. Some of the actual performance characteristics are also given for reference. 6 H H OOOOO H H O O HHHHHH 222 O O 222 H H 2 2 O O 2 2 H H 2 OOOOO 2 2222 2222 2 2 22222 22222 HYDROGEN/OXYGEN ROCKET ENGINE ANALYSIS PROGRAM Version 3.12 (c) December, 1987 Software Package by Kerry Hicks, MS Analysis of SSME (Rockwell International -- Rocketdyne Division) Study Initiated on 12-30-1987 at 21:56:45 ENGINE SPECS: ------------- AREA OF NOZZLE THROAT 0.5749E+00 SQUARE FEET AREA OF NOZZLE EXIT 0.4456E+02 SQUARE FEET AREA RATIO: 77.51 : 1 CHAMBER PRESSURE 0.2021E+03 ATM OXYGEN TO HYDROGEN MASS FLOW RATE: 6.000 : 1.000 ADIABATIC FLAME TEMPERATURE: 3614.9 Kelvin ********** COMBUSTION CHAMBER DETAILS *********** -------------------------- Temperature=3614.85 Kelvin Reaction Equation Coefficients and Mole Fractions: 7 Diatomic Hydrogen N=0.6802E+00 X=0.2477E+00 Diatomic Oxygen N=0.6736E-02 X=0.2453E-02 Water N=0.1878E+01 X=0.6837E+00 Monatomic Hydrogen N=0.7292E-01 X=0.2655E-01 Monatomic Oxygen N=0.6216E-02 X=0.2263E-02 Hydroxyl N=0.1027E+00 X=0.3739E-01 Total N=0.2746E+01 Molecular Weight of Mixture=0.1359E+02 Qin=+1.0340E+02 kcal Qout=+1.0340E+02 kcal Qnet=+1.1978E-03 kcal P=0.2021E+03 atm S=0.5571E+02 cal/(mole K) Ratio of specific heats: 1.196 *********** FROZEN FLOW CALCULATIONS ********** ------------------------ Average ratio of specific heats: 1.234 Mass flow rate (mdot): 0.1062E+04 lbm/sec. Pressure at exit: 0.1571E+00 atm. (0.2308E+01 psia) Temperature at exit: 930.51 Kelvin Exit velocity: 0.1366E+05 ft/sec. Thrust at sea-level: +3.7140E+05 lbf. Thrust at 10,000 ft: +4.0085E+05 lbf. Thrust at 25,000 ft: +4.3071E+05 lbf. Thrust at 50,000 ft: +4.5491E+05 lbf. Thrust at 75,000 ft: +4.6242E+05 lbf. Thrust at 100,000 ft: +4.6470E+05 lbf. Thrust at 150,000 ft: +4.6557E+05 lbf. Thrust in a vacuum: +4.6570E+05 lbf. 8 ********** EQUILIBRIUM FLOW CALCULATIONS ********** ----------------------------- EQUILIBRIUM FLOW EXIT PROPERTIES: Temperature=1153.85 Kelvin Reaction Equation Coefficients and Mole Fractions: Diatomic Hydrogen N=0.6457E+00 X=0.2440E+00 Diatomic Oxygen N=0.8043E-18 X=0.3040E-18 Water N=0.2000E+01 X=0.7560E+00 Monatomic Hydrogen N=0.1081E-07 X=0.4086E-08 Monatomic Oxygen N=0.1493E-17 X=0.5641E-18 Hydroxyl N=0.8088E-10 X=0.3057E-10 Total N=0.2646E+01 Molecular Weight of Mixture=0.1411E+02 Qin=+2.8083E+01 kcal Qout=+1.1560E+02 kcal Qnet=-8.7513E+01 kcal P=0.1571E+00 atm S=0.5783E+02 cal/(mole K) Average ratio of specific heats: 1.234 Mass flow rate (mdot): 0.1062E+04 lbm/sec. Pressure at exit: 0.1571E+00 atm. (0.2308E+01 psia) Temperature at exit: 1153.85 Kelvin. Exit Velocity: 0.1453E+05 ft/sec. Thrust at sea-level: +4.0027E+05 lbf. Thrust at 10,000 ft: +4.2972E+05 lbf. Thrust at 25,000 ft: +4.5958E+05 lbf. Thrust at 50,000 ft: +4.8378E+05 lbf. Thrust at 75,000 ft: +4.9129E+05 lbf. Thrust at 100,000 ft: +4.9357E+05 lbf. Thrust at 150,000 ft: +4.9444E+05 lbf. Thrust in a vacuum: +4.9457E+05 lbf. Normal Termination on 12-30-1987 at 21:57:29 9 These estimates compare to the actual values of: Thrust: 375,000 lbf (SL), 470,000 lbf (Vacuum) Mass Flow Rate: 1030.9 lbm/sec Ratio of specific heats: 1.2 Now, just for grins, we can see what happens if we were to replace the oxygen with fluorine by running H2F2. This example also demonstrates what happens when you try to analyze an engine that causes numerical difficulties. Note that the program failed while trying to do the equilibrium flow calculations. H H FFFFF H H F HHHHHH 222 FFFF 222 H H 2 2 F 2 2 H H 2 F 2 2222 2222 2 2 22222 22222 HYDROGEN/FLUORINE ROCKET ENGINE ANALYSIS PROGRAM Version 1.01 (c) December, 1987 Software Package by Kerry Hicks, MS Analysis of SSME -- Running on Fluorine and Hydrogen Study Initiated on 12-30-1987 at 21:58:39 10 ENGINE SPECS: ------------- AREA OF NOZZLE THROAT 0.5749E+00 SQUARE FEET AREA OF NOZZLE EXIT 0.4456E+02 SQUARE FEET AREA RATIO: 77.51 : 1 CHAMBER PRESSURE 0.2021E+03 ATM FLUORINE TO HYDROGEN MASS FLOW RATE: 6.000 : 1.000 ADIABATIC FLAME TEMPERATURE: 3329.7 Kelvin ********** COMBUSTION CHAMBER DETAILS *********** -------------------------- Temperature=3329.69 Kelvin Reaction Equation Coefficients and Mole Fractions: Diatomic Hydrogen N=0.2100E+01 X=0.4753E+00 Diatomic Fluorine N=0.2853E-08 X=0.6456E-09 Hydrogen Fluoride N=0.1999E+01 X=0.4525E+00 Monatomic Hydrogen N=0.3183E+00 X=0.7205E-01 Monatomic Fluorine N=0.8963E-03 X=0.2029E-03 Total N=0.4418E+01 Molecular Weight of Mixture=0.1009E+02 Qin=+1.1296E+02 kcal Qout=+1.1294E+02 kcal Qnet=+1.9424E-02 kcal P=0.2021E+03 atm S=0.4446E+02 cal/(mole K) Ratio of specific heats: 1.300 *********** FROZEN FLOW CALCULATIONS ********** ------------------------ Average ratio of specific heats: 1.354 Mass flow rate (mdot): 0.9851E+03 lbm/sec. Pressure at exit: 0.9154E-01 atm. (0.1345E+01 psia) Temperature at exit: 444.62 Kelvin Exit velocity: 0.1399E+05 ft/sec. Thrust at sea-level: +3.4281E+05 lbf. Thrust at 10,000 ft: +3.7226E+05 lbf. Thrust at 25,000 ft: +4.0212E+05 lbf. 11 Thrust at 50,000 ft: +4.2632E+05 lbf. Thrust at 75,000 ft: +4.3383E+05 lbf. Thrust at 100,000 ft: +4.3612E+05 lbf. Thrust at 150,000 ft: +4.3698E+05 lbf. Thrust in a vacuum: +4.3711E+05 lbf. ********** EQUILIBRIUM FLOW CALCULATIONS ********** ----------------------------- Numerical Difficulties Encountered -- Not Calculated. Normal Termination on 12-30-1987 at 21:59:08 ------------ As an example of a Hydrogen/Fluorine engine for which the equilibrium flow can be calculated, try running this: Area of throat: 1 sq. ft. Area of exit: 10 sq. ft. Pressure: 27 atm. Mass flow ratio: 6:1 --- LIMITATIONS OF H2O2 AND H2F2 --- -- Because the thermochemical data used is only accurate to 3 or 4 digits, the results generated cannot be expected to be any more accurate than this. -- Temperatures must be between about 300 K and 6000 K and exit mach numbers must be less than 50. This covers the vast majority of realistic engines. 12 -- The reactants are assumed to be injected into the combustion chamber at their normal boiling points. For most rockets, this is a valid assumption. Note that this restriction is EASILY removed by modifying only only one line in the source code. -- For numerical (as well as practical) reasons, mole fractions less than 1.0e-30 are considered to be 0.0. --- MISCELLANEOUS NOTES --- -- I ran H2O2 on a wide variety of engines, ranging in thrust from 15,000 lbf to 250,000 lbf. The program appears to handle all realistic engines in this range. I can't make any promises as to the reliability/accuracy of H2O2 outside of this range. (I don't have any actual performance data for smaller/larger engines!) Far fewer test cases were run on H2F2. The test cases I had were for the AFT calculations only (they checked out). The thrust calculations are assumed to be correct since the code is identical to that in H2O2. -- For the Hydrogen/Oxygen engines I had actual performance data on, I found that the following "fudge factors" allowed me to better compare the program output to the actual test data: Actual thrust = .506 * (Frozen Thrust) + .476 * (Equilibrium Thrust) Actual mass flow rate = .988 * (predicted mass flow rate) Of course, this may or may not be universal. The thrusts I found using this equation came a little closer to the actual values than did a simple averages of the Frozen and Equilibrium Thrust values (typically). It is question- able whether these fudge factors will work on your engine, especially if it is out of the range 15,000 - 250,000 lbf. (Note that the actual thrusts tend to be weighted towards the Frozen Thrust value -- this is *probably* a general trend for engines of this class.) (No such fudge factors have been calculated for hydrogen/fluorine engines using H2F2.) 13 -- The source code was compiled with QuickBasic (Version 3.0). For the most part, TurboBasic can also be used, but if you plan to modify the code and compile using TurboBasic, be aware of the following problems that I ran into with TurboBasic: TurboBasic (Version 1.0) chokes on the formatted output written directly to the printer, ie, when you select "LPT1:" as the output file. Also, TB craps out on SQR(x) when x is close to zero after several thousand mathematical operations. (That's why I've used x^.5 in the defined functions in the program.) These problems may or may not be specific to my program/computer combination, so you may or may not encounter them. (TurboBasic is a copy- right of Borland International and QuickBasic is a copy- right of Microsoft Corporation.) -- If you modify a COPY of the source code to run on another computer and plan to upload it to a BBS, DOCUMENT IT! Add a line to the modified code saying something to the effect "Modified by Ima Hacker for the H-89." USE A DIFFER- ENT NAME FOR YOUR VERSION! (Something like H2O2H89.BAS.) If you upload your modified code, upload this documentation as well as the ALL of the ORIGINAL files in this package. Put any special instructions for your version in a READ.ME2 file. (This may sound like a lot of extra nonsense, but it will help keep this software package complete and docu- mented.) -- The source code is capable of producing much more output data, including data for composition -vs- temperature graphs! A few well-placed print statements can really increase the output you have to "play" with. -- As an indication of how flexible the source code is, consider that, with the exception of typing in the JANAF data, the conversion of H2O2 to H2F2 only took about 20 minutes! -- The purpose of this package is NOT to encourage students to avoid writing the thermodynamic programs required for propulsion classes. It is merely a reliable series of programs that will allow the student to verify the operation of his/her program or manual calculations. -- Run times for this version of H2O2 are about 1 minute on an 8 MHz XT clone with a math coprocessor and about 6 1/2 minutes on an AT without a coprocessor. H2F2 times are less -- just under a minute and about 5 minutes, respectively. 14 -- Questions and comments can be directed to me, Kerry Hicks, on the following BBS system: Kyle's BBS (513) 236-7085 -- If you find this program to be useful, I'd like to know about it. Drop me a note on the above BBS. --- Update History --- H2O2| ----- Version 3.12 (Dec., 1987): -- Oops....a typographical error was found in the thermochemical data. The effect of this error was, for all practical purposes, limited to the Adiabatic Flame Temperature calculations. This error has been corrected and the remaining thermochemical data double-checked. -- A few more safeguards against user error have been added. -- The manual has been revised to reflect the introduction of H2F2 to the software package. -- Numbers less than 1.0e-30 are rounded to 0.0 for printing. ------------ Version 3.11 (Dec., 1987): -- Not released to Public Domain. 15 ------------ Version 3.10 (Dec., 1987): Okay, okay......so I left out some of your sugges- tions. It's not like I shot your dog! Here are the latest additions and modifications: -- Date and Time stamping at beginning and end of calculations. -- Even neater output. -- Better error recovery. The program now avoids aborting on many BASIC errors such as divide by zero, disk full, and media errors. -- Some attempt has been made to detect and/or recover from USER errors. It's not idiot-proof, but it does catch many of the common data-entry errors such as bad files names. -- More program variables are documented/declared in the source code. ------------ Version 3.00 (Oct., 1987): This is, hopefully, the last major revision I will make in this software package. This update incorporates most of the suggestions made by users. These changes are: -- Speed enhancements: Typical times are less than one minute on a Turbo-XT with a math coprocessor and just over 7 minutes on an AT without a coprocessor. -- More Altitudes in Thrust Calculations: Now com- putes thrust at 8 altitudes instead of just 3. -- Runaway Detection and Continuation: When the program detects what it thinks is a non-con- verging solution it halts execution and gives you the option of overriding the abort. This lets you decide if you want to allow the program to iterate further. The time allowed for this can be modified by changing a line in the source code. 16 -- Neater, more organized output. -- The source code takes better advantage of Quick- Basic features. This means it will no longer run under GW-BASIC. (QuickBasic is a copyright of Microsoft.) ------------ Version 2.10 (Oct., 1987): The thermochemical data has been made internal to the program. This saves read-time for floppy-based systems. There is no longer a separate executable file for computers with and without the math coprocessor. H2O2 detects and uses the processor if present. If it is not, then its function is emulated. The manual has been updated to reflect the changes. ------------ Version 2.01 (Aug., 1987): The file SAMPLES has been removed from the H2O2 software package and the file H2O2.BAS has had the "meat" cut out of it. H2O2.BAS is now just the top of the file containing the comments, documentation, and variable input. This was done for a variety of reasons. However, if someone has a legitimate reason for wanting the source code or the samples, he/she can still drop me a note explaining why on one of the BBS's mentioned in the manual. I apologize to those of you with computers that cannot run the executable versions of the program. When time permits, I expect to produce a much smaller BASIC ver- sion for 64k machines, but until that time, no source code will be included in the PD version of this software package. ------------ Version 2.0 (July, 1987): It has been noted that the executable programs will 17 NOT run on a Z-100 (non-PC) computer. Attempting execution causes a "Wild Interrupt" error. The BASIC version will work, however. ------------ Version 2.0 (June, 1987): Original Public Domain Version of the H2O2 Package. ----------------------------------------------------------- H2F2| ----- Version 1.01 (Dec., 1987): -- First Public Domain Version of H2F2. ------------ Version 1.00 (Dec., 1987): -- Not released to Public Domain. This was derived from Version 3.11 of H2O2. 18