Modeling of an Exhaust Gas Cooler in a High-Altitude Test Facility of Large-Area Ratio Rocket Engines

In this numerical study, the cooling of exhaust gas issued from a rocket engine in a ground test facility has been investigated by solving the three-dimensional governing equations. Simulations have been performed by employing discrete phase model with plain-orifice atomizer to cool the exhaust flow effectively by injecting the coolant (water) in the form of a fine spray. The effects of coolant flow rate, inlet gas temperature, injection pressure, injector diameter, gas cooler length, and distribution of water droplets on the cooling characteristics, such as the temperature at the gas cooler exit, droplet diameter, and percentage of unevaporated water have been discussed in detail. Simulations highlight that optimum particle diameter needs to be identified for effective cooling, and also uniform cooling of the exhaust gas is attained by employing staggered injector distribution (more injectors at the periphery compared to the core region). Predicted values of static temperature and pressure agree well with the experimental data obtained from a scaled-down model high-altitude test facility. (C) 2014 American Society of Civil Engineers.