TESTING FIREBALL DIAMETER AND DURATION OF 227 GRAM CARTRIDGES CONTAINING ISOBUTANE

The aim of the work was to verify equations describing the diameter and duration of the fireballin relation to small tanks containing LPG. As a result of testing small, three-piece bayonet-typecartridges containing 227 g of isobutane, it was observed that the fireball parameters may varysignificantly depending on the discharge direction of the medium. After the bottom gas discharge(BD) the fireball was found to have a significantly larger observed diameter than during thetop discharge (TD), amounting on average to 4.58 and 3.63 m, respectively. An analysis of themaximum fireball diameter (rF), the total fireball duration (tF) and the time to reach the maximumfireball value (tMR) has shown that in the case of TD there is significantly greater convergence withrelationships presented in the literature than is the case with BD. Comparing the static fireballmodels, it can be noticed that for the TD tests the rF values the closest to experiment are obtainedin the case of the Williamson&Mann, Hasegawa Sato (1977), Lithiou&Maud (butane) and CCPSequations. In the case of BD tests, convergence with models is much lower, with the smallest errorobserved for the relationship presented by TNO (12.5%). The tMR and tF values calculated for thedynamic models of Martinsen & Marx and Pritchard are much shorter than those obtained in theexperiment, and greater deviations may be noticed in the case of BD, especially in relation to thePritchard model. The research showed that the fireball growth rate for the tested cartridges is muchlower than predicted in the analysed models.