Model for choosing optimal water flow rate for tank wall cooling

Abstract

In this paper, we have considered the problem of choosing the optimal water flow rate for cooling the tank wall with water in the event of a fire in the adjacent tank. The optimal water flow rate is understood as the minimal flow ensuring a sufficient level of cooling. The choice of the water flow rate is based on the solution of the thermal balance equation for the tank wall and the thermal balance equation for the water film. The model takes into account the radiant heat transfer between the flame, the tank wall, the environment and the internal space of the tank. The convective heat transfer from the tank wall to water and vapor-air mixture is also taken into account. Here, we have developed an algorithm for determining the optimal water flow for cooling the tank wall. Solving the problem of choosing the rate of the cooling water flow is reduced to the sequential solution of the problems to determine the temperature distribution along the tank wall and the water film. We have constructed the functional dependence of optimal water flow rate for tank cooling on the direction and velocity of the wind. The inclination of the flame by the wind towards the adjacent tank increases the relevant heat influx, which requires a greater intensity of cooling. On the contrary, when the direction of the wind is away from the adjacent tank, the heat flux decreases. At the same time, for wind velocity greater than a certain value, the heat flux decreases to such an extent that there is no more need to cool the walls of the adjacent tank. With the perpendicular direction of the wind, at certain velocity values, there is no need to cool the walls of the adjacent tank either. The obtained results can be used to determine the rate of water flow for cooling the tank wall in the event of a fire in an adjacent tank.