Vol.3, No 11, 2001 pp.277-284
UDC 536.2:662.33(045)

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NUMERICAL COMPUTATION OF UNSTEADY
HEAT TRANSFER THROUGH POWDER GRAIN
Ljubiša Tančić¹, Miloje Cvetković^2
1Military Technical Academy of Yugoslav Army
11133 Belgrade, Žarkovo, Ratka Resanovića 1
²Department of scientific and publishing activities,11000 Belgrade Neznanog Junaka 38

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Abstract. The interior ballistics problem of firing process in the small arms is considered. A mathematical model of a so called two-phase flow, which is created by gas - dynamic partial differential equations system, is used. Partial differential equation system has been solved numerically by finite difference method. Heat quantity which is crossing from powder gasses to powder grains, is determined, because this heat figures in flow energy equation. The equation of temperature distribution through deepness of powder grain is defined. As the example of numerical treatment of two-phase flow the numerical modeling of two-phase flow of powder grains and their combustion products in small arms barrel is shown. The operating conditions and shape of powder grains are variationed and their influence to the calculation results are numerically analyzed. Temperature distribution through deepness of powder grain is variationed and its influence to the calculation results is numerically analyzed. The whole procedure is included in a computer program, which results are verified through the comparasion with experimental results. The numerical results are analyzed and they compared with the experimental results and some conclusions for the future work on this problem are given.

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NUMERIČKI PRORAČUN NERAVNOMERNOG PRENOSA TOPLOTE KROZ PRAH BARUTA (BARUTNI PRAH) Razmatra se unutrašnji balistički problem procesa opaljivanja u oružju malih dimenzija. Koristi se matematički model takozvanog dvofaznog strujanja koje stvara gas, predstavljen sistemom dinamičkih parcijalnih diferencijalnih jednačina. Sistem parcijalnih diferencijalnih jednačina rešen je numerički primenom metoda konačnih razlika. Određena je količina toplote koja prelazi iz barutnog gasa u barutni prah, zbog toga što ova toplota figuriše u jednačini energetskog bilansa (toka energije). Jednačina raspodele temperature kroz barutni prah je definisana. Kao primer numeričkog rešavanja dvofaznog strujanja, prikazano je numeričko modeliranje dvofaznog strujanja barutnog praha i produkta njegovog sagorevanja u oružju malih dimenzija. Menjani su radni uslovi i oblik zrna baruta i numerički je analiziran njihov uticaj na rezultate proračuna. Menjana je i raspodela temperature kroz barutni prah i analiziran njen uticaj na rezultate proračuna. Čitav postupak je obuhvaćen kompjuterskim programom, čiji su rezultati verifikovani poređenjem sa eksperimentalnim rezultatima. Numerički rezultati su analizirani i upoređeni sa eksperimentalnim rezultatima, a dati su i neki zaključci za budući rad na ovom problemu.