Abstract:

In order to improve the accuracy of fire water cannon jet trajectory prediction and overcome the difficulty of traditional parabolic theory to describe the phenomenon that "when the initial velocity is constant, the range increases with the increase of jet flow", first of all, the Euler method was used to establish a one-dimensional mass conservation equation along the trajectory of the water jet in the air, axial momentum conservation equations and the radial momentum conservation equations. Then, assuming that the axial velocity distribution of the water column and air column was in the shape of "bowler hat", the established conservation equations were derived and analyzed, and the fire water cannon water jet trajectory calculation model was established. Finally, based on three conservation equations, the numerical computation process of the jet trajectory model was given and verified with the collected experimental data. The results show that the error of this model is less than 10%.

Key words: Euler method, jet trajectory, fire water cannon, range, entrained air