COMBINED CORRELATION TO PREDICT TRAJECTORIES OF AIRBLAST SPRAY AND JET IN CROSS-FLOWS—INDEPENDENT OF TWO-PHASE MOMENTUM RATIO

Abstract

Most of the trajectory correlations of spray in cross-flow rely on a two-phase momentum ratio (q2). However, insufficient information about injector geometry might pose difficulty in the calculation of q2 and result in significant errors in the predictions of trajectories. In this work, a new empirical correlation is developed; the correlation is independent of q2 and can be used to predict windward trajectories of both airblast spray and jet in cross-flow. The momentum of spray droplets is accounted for by using thermophysical properties of liquid and operating conditions; these parameters also control drop sizes in airblast sprays. The validity of the correlation is established by comparing the predictions with current and past experimental measurements on different liquids, including water and hydrocarbon fuels; the predictions from past empirical correlations are also included in the analyses. The correlation shows good agreement with the experimental spray trajectories of water and fuel sprays in cross-flow with a mean absolute percentage error (MAPE) of 13.9%. The correlation is extended to predict trajectories of airblast sprays injected in evaporative cross-flows; this is achieved by introducing a temperature-ratio term in the trajectory correlation. The predictions of temperature-dependent trajectory correlation agreed well with available experimental data on various fuels, viz., ethanol, Jet-A, and decane with maximum MAPE up to 15.89%. Further, the trajectory correlation of airblast sprays in cross-flow reduced to a power-law functional form of trajectory equation for classical jet-in-cross-flow configuration, which provides reasonable agreement (MAPE ∼ 14.58%) with the experimental data on different liquids such as water and the hydrocarbon fuels. © 2022 by Begell House, Inc.