The coupled interaction of cold liquid sprays and a hot gas stream is analyzed. The effect of liquid droplets introduced into a hot gas stream flowing in channels of constant and of varying areas is investigated as a rapid cooling process for a hot gas discharge. The effects of spray distribution, duct geometry, and wall friction are examined. Variations of gas and liquid spray properties such as gas temperature and velocity, droplets velocity, temperature, and distribution are presented as a function of distance along the duct in the direction of flow. The effectiveness of this rapid cooling process for a hot gas flow is assessed.