Interior ballistics of high velocity gun, version 2 (IBHVG2). A user's guide

180 Pages·6.131 MB·English

by  Anderson. R., Fickie. K.

Interior ballistics
of high velocity
gun
version 2
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Other requests shall be referred to
Director, U.S. Army Ballistic Research
Lab., Attn: SLCBR-DD-T, Aberdeen Proving
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ir FILE COr6
TECHNICAL REPORT BRL-"'R-2829,
IIBfVG2 A USER'S GUIDE
RONALD D. ANDERSON
KURT D. FICKLE DTIC
tEL
Ic.
JULY 19$7 T
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US ARMY NALL13TIC f1tESARCH LAWOPATORY, AlN. U48DRDO0T,
A3DEA02m PROVING CROVINII) ho 234014M
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Errata Sheet for BRLýTR-2829, "IBHVG2 - A USER'S GUIDE'
Page Description
41 After equation (A.14), reference to 'Figure 6' should be 'Figure 7'
43 Section C, first paragrab, last sentence: "...tube-based frame of
reference (Figure 6), where z. -(cid:127) x, + x, , is as follows."
49 Equation (D.18) should be:
A,- , j1Db,+ ZAh,+ rbb [z, - t(O)1
1
Equation (D.21) should be:
2 .
50 Section E, third paragraph, second sentence: "These codes solve for
surface area and unburned volume for the differcnt grain types..,"
55 Subscript definitions, last line should have" 0" (zero) instead of"*" (phi)
58 Graph at bottom of page should have following axis labels:
Horizontal axis "Depth Burned (in)"
Vertical axis "Surface Area (in )"
61 Appendix D, first paragraph, end of third sentence: "...integration
step size (DELT in the $INFO deck)."
62 Appendix F., third paragraph, second sentence: "...case 5 took more
time to compute on the Cray and the PC than..."
73 Test Case 2, second parograph, end of fourth sentence: %.1RAJ,a nd
$INFO decks, and the graph at the end of Appendix B.)"
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BallisticResearchLabortory - SLUMB-IA ______________________
Sc. ZaOOES isy.EM 'Stste, sew ZIP COWt ?h &DOWRS5(M' uw adW'ru
,
Aberdeen Proving Ground. MD 21005-5066____
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;U.NAE B; "FUNOING/'SPONMOING SbOFFICE %YM43'L 9. ;AOCtUMMEN? INSTRrrIEME1 '1OENTIPUTIO4 NMUMBR
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ELEMENT MO. NO. NO. ACCESSION No
1Ll61102A_43_:
_______________________________61102A 00
I I, TITLE ;;Vlej ;=;nt C Riasktuon)
IBHVG2 - A User's Guide
23 PESON-AL AUTHOR(S
Ronald D. Afldersoo and-Kur D. lFickie
Ile TYPE OF REPORAT 13b, tIMIE CoveREio 14 tOAOTRf EPORT (Yee., W£D7) tA IS. PAGE COUNT
Technical Report IFROM 13-fL.. TO Jaoi
16. SUPPLEMENTARY NOTATION
17 COSz~l CcO DES M70 TTEUNSSJ P(Coi u~e~.wv wsy-Etb~ yboknm
F'EL0 CR OUP ?U X0,11161" I
I 01 Interior Ballistics. Guns, High Velocity, Propellanits
1.AASTRACT (ContimieOo n~"f WVr n ftr;b 1r ;7 7
I 8HVG02, which stands for Olntetior Ballistic% of Hligh Velocity Guuns, version 2,w .i~s a lumpcd-paramcter, interior
ba3llistic computer code. The code, which was developed at the 18RL, is an updated version of the classic B~aer.
Fr'Ankle interior ballistic code. I8H-VG2 is used for calculation or interior ballistic trajectories, including gas
pressure, projectile displaccment and pro eti~lc velocity as a function of time. The code treats both regular and
deterred propellants, It contains po*crful variational and searching capabilties so that it can. for excample, search
and rind ths/best prop-llant dimensions, given the maximum allowable gas pressure.
This report thoroughly doct~mcrits IBHV02, so that all of its many features can be used effectively. The report
contains a detailed description of the range or possible user input and a dewciptior. of both the algorithms embodi-d
along with the FORTRAN subroutine's which implement them, There are also complete examples of input and output
from the code. Although the code hat been written to L! as generally applicable as possible, the report has a shott
sectioa' describing modirications that are necessa3r to enable the code to run on various computers and comtpiler
combination$. A Mach ine~ucadaole copy or the codc can be obtained by contacting the authors or this rcport.
,
JO0D1T il-IutJTION/AVAILASgLITY OF ABSTRACT 'I AOSTRACT SECURITY CLA5WIFCATION
~1KlUNClLAS5IF1IED/UNL1MITf0 03 SAMIE AS RPT 0 Wr'C usr*s Un14lassile
_____
V~nNAUS1&1 n e c'' IsnD UA (301) 27"102 SLCl3R-10-A
DDF O1M47 . . AR ;3 APFZ47 0tiQflmi*omsw b itw 004vlted xi t CAS.'Np~ A(
All othof Eatt n$ 4( )M,' UNCLASSI FIED
Noec Lert
lntentiontly bllank
CONTENTS
L INTRODUCTION ............. . . . . 4
IL DESCRIPTION OF INPUT DECKS. . ............. . S
a
A. Syntax Rules . . . . . . . . . . . . . . . .
B. Deck% . . . . . . . . . . . . . . . . . . . . . . . . . 9
1I. SUBROUTINE DESCRIPTIONS ................. 29
IV. ALC-OIITHM DESCRIPTIONS ................. 39
A. Calculation of Mean Temperture and Pressure ........... 39
S. Dynamic Relations . . . . . . . . . . . . . . . . . . . . . 41
C. Calculation of the Prt;ssure Gradient ..... . . . . . . .. . 43
D. Work and Losses . . . . . . . . . . . . . . . . . . . . . 46
. Proptliant Grain Geometry . .... . ... . .. . . . ... 50
V. APPENDICES . ...... ...... .. ... .. . .. . 54
A. Nomenclature ........... . . . . ............ 54
a. Propllant Grain Configurations . . . ... .. . . . .. . .. 56
C. Istallation ............. ........................ ... 59
D. Hug ................ ....................... . . 61
E. Samle Input Decks and Outputs ......... ................ ... 62
Test Case I ................ ....................... ... 63
Test Case 2 .... .......... . . ............. 73
Test Case 3 . . . . .. ... ... .. . .. . .. . . 90
Test Cam 4 . . . . . . . . .. . .. . .. . . .. . 114
TomC' ase35 ...... ...................... 128
Tesi(Case 6 ...................... ...................... 143
VL REFERENCES . . . . . .............. 13
VIL ACKNOW1 EDGEMENTS .............. ... .. 164
xofA ee ston Por
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JuStufieatio
AvalAbiltty Codo"
3A vail ad or- ---
I. INTRODUCTION
The effcient design or large caliber guns and their corresponding charges requires an
accurate simulation of :he interior ballistic cycle. Simple lumped-parameter models are usu-
ally sufficient to predict the gross ballistic variables such as chamber pressure .nd projectile
velocity to precision rivaling experimental capabilities. This accomplishment allows ballisti-
cians to focus on experiments wiki.h either validate the models or ar- used to extend the
modeling effort. Since computer simulation is very inexpensive in rel3tion to experimental
testing, once it has been established that the model corresponds to actual firings, the designer
can try out many different ideas under a variety or circumstances. The net result is a superior
round at minimum cost.
This report describes one such code which is widely used in the interior ballistics com-
munity. IBHVG2, %hich stands for "Interior Ballistics of High Velocity Guns, version 2", was
developed by describing the ballistic events as a set of ordinary differential equations which
are solved by marching forward in time. One feature which has helped to popularize the code
is its flexible method or inputting user options, allowing the designer to focus his energies on
the ballistics instead of the computer programming aspects. Past experience suggests that
IBHVG2 is general enough to investigate most gun/charge scenarios without any modifica-
tions to the computer algorithms.
Most useful computer codes are the product of evolution and IBHVG2 is no exception.
The basic principles are described in the %ell-known Baer-Frankle reportfIl. IBHVGI, which
was written by Robert Dea of BRL, is essentially the Baer-Frankle methodology written in
FORTRAN with an improved user-interface. Some ideas were also borrowed from
MPRGUN written by Paul Baer, also of BRL. In 1981, mission requirements dictated that a
new code be written which would properly model deterred propellants and provide a better
description of heat transfer to the gun tube. Franz Lynn was the sole author of the coding
eWfortm, although numercus discussions among the scientists in the Interior Ballistic Division of
BRL helped shape the final form and goals, Development ceased after his untimely death in
1983.
The basic operatiun of the code, is quite simple. From a sufficient description of the gun
system and its propelling charge, IBHVG2 can simulate the burning of the primer and propel-
lant while computing the time trace of a variety of variables to include: mean gas pressure
and temperature of the gun chamber, acceleration and velocity of the projectile, and the maws
fraction of each unburned propellant. One of the advanced features of the code is the ability
to automatically vary its inputs for a new simulation in an iterative fashion. This is very use-
ful for charge design work. As an illustration, the ballistician could fix the maximum allow.
able gun tube pressure and require the code to vary some characteristic of a specific propel-
lant (say, the grain web size) until the goal is attained. Such iterations can, in turn, be nested.
Extending our example, one may desire to meet the target pressure while optimizing on the
exit velocity of the projectile by varying another propellant characteristic, Detailed examples
are inclu&dd in Appendix E to serve as a guide to the reader and to demonstrate Ihe versatil-
ity of the code.
Figures I and 2 are included to demcnstrate the correspondence between range firing data
and IBHVG2 simulations, The data come from a series of experiments investigating short,
slotted sticks (25-mm) fired in a 15-mm howitzer (see reference 121). They are represcntative
or results one would expect for granular Charles in a large caliber weapon. The input for
computer simulation is based on propellant data obtained from closed-bomb experiments and
4