Abstract:
Spray cooling is a technology of increasing interest for the high heat flux application, featuring high heat transfer, rapid cooling, and less cooling water consumption. In this work, a numerical study was carried out on the process of cooling water spray shock chilled syngas in the pipeline. To determine the influences of different initial conditions on velocity field and temperature field in the pipeline, numerical studies were performed by varying the nozzle diameter, nozzle spray half angle, and the cooling water mass flow rate. Based on the Euler method, the gas phase flow field in the pipeline was calculated using realizable
k-
ε turbulence model. Based on the Lagrange method, the droplet trajectory was calculated using the stochastic trajectory model. And the interphase mass and heat transfer between the gas phase and the droplet were solved by the bidirectional coupling method. Simulation results showed that reducing the nozzle diameter, increasing the nozzle spray half angle, or increasing the cooling water flow could reduce the syngas temperature. By using a pressure swirling atomizing nozzle with the diameter of 6 mm and the spray half angle of 70°, the syngas(7472.99 m
3/h) temperature could be reduced from 1523.31 K to 1273.15 K when the cooling water flow rate was 1.41 kg/s. Effective cooling of the syngas before the fire tube waste heat boiler is achievable and can be used for the optimization of the operation environment of waste boiler.