ASTM_D_2541_-_93.pdf

Designation:D 2541 93Standard Test Method forCritical Diameter and Detonation Velocity of LiquidMonopropellants1This standard is issued under the fixed designation D 2541;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method2covers the evaluation of two proper-ties of a high-energy liquid propellant.In one form,the criticalinternal diameter is determined in a given type of metal orplastic tubing below which propagation of stable high-velocitydetonation will not take place.In the alternative form,whichuses more material,detonation rate is concurrently measured.The composite donor of either size may be used in mostinstances to initiate detonation in experimental trap designs.1.2 This standard does not purport to address all of thesafety problems,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.2.Terminology2.1 Definition:2.1.1 critical diameterthe largest diameter that will notdetonate when the donor is exploded.3.Summary of Test Method3.1 Various diameters of tubing are filled with propellant,and an attempt is made to cause the propellant to detonate byuse of a secondary detonating medium(the donor).4.Significance and Use4.1 It should be emphasized that the critical diameter,asdetermined under these conditions,is valid only for theseconditions and is not an intrinsic property of the sample.Onevital parameter in establishing the critical diameter is that ofconfinement of the test specimen.The fact that detonationoccurs or does not occur in Type 347 stainless steel tube doesnot necessarily imply that the same results would be obtainedin an aluminum,copper,glass,etc.,tube of similar dimensions.Type 347 stainless steel tube is acceptable for a standardreference test,but for practical application,diameters should bestudied in the materials and wall thicknesses proposed for use.4.2 When working with high-energy liquid propellants,serious consideration shall be given to the possibility that adetonation originating in the engine can propagate upstream tothe propellant tank and cause a disastrous explosion.Therefore,it is useful to know the minimum diameter of propellant linethrough which a detonation of the propellant in question canpropagate.If it is impracticable to use propellant lines smallerthan this minimum,it will be necessary to design and testdetonation traps in larger lines.The minimum or criticaldiameter(often referred to as“failure”diameter),when theconditions are properly defined,can be a useful measure of theshock sensitivity of similar systems.The detonation velocity ofthe propellant in question is another property of interest.4.3 The three determinations,namely:minimum diameterfor propagation,detonation trap requirements,and detonationvelocity,have much in common;all presuppose the initiationof a stable detonation in a liquid contained in a tube.The keyto the present test method is the use of a donor stage consistingof the material under test.Although a compound initiatorcomprised of a blasting cap and high-explosive booster isemployed,the true donor is a length of the subject materialsufficient to assure establishment of a stable detonation char-acteristic of the test medium ahead of the first test section ormeasuring station.Questions of wall and boundary discontinu-ity are thereby eliminated along with the accompanyingcomplications of impedance mismatch and perturbation of theshock front.5.Apparatus5.1 The liquid under test,depending on what measurementor measurements are to be made,shall be contained in one ofthe following three assembled units:5.1.1 Assembly No.1,Critical Diameter Measurement(Fig.1(a):5.1.1.1 Section A,Fig.1(a),shall consist of Type 347stainless steel tubing(1-in.(254-mm)outside diameter by0.049-in.(1.24-mm)wall thickness by 6-in.(152-mm)length).When filled with test sample,it is considered the“self donor”section.1This test method is under the jurisdiction of ASTM Committee F-7 onAerospace Industry Methods and is the direct responsibility of SubcommitteeF07.02 on Propellant Technology.Current edition approved March 15,1993.Published May 1993.Orginallypublished as D 2541 66 T.Last previous edition D 2541 83.2This test method is identical in substance with the JANNAF method,“CriticalDiameter and Detonation Velocity Test,”Test Number 8,Liquid Propellant TestMethods,May 1964,published by the Chemical Propulsion Information Agency,Johns Hopkins University,Applied Physics Laboratory,Johns Hopkins Rd.,Laurel,MD 20707.1Copyright ASTM,100 Barr H