Abstract
Abstract - The performances of single hydrazines and hydrazine mixtures burning with NTO in a bipropellant rocket combustion chamber are compared. Systems using single hydrazines (N2H4, MMH, UDMH) and hydrazine mixtures MMH=N2H4 and UDMH=N2H4) were simulated with total mass flow rates of 45:29 g=s and 89:25 g=s, respectively, in a chamber with diameter 40 mm. A one-dimensional mathematical model was developed, assuming that combustion and turbulent mixture processes are controlled by droplet vaporization, and that droplet diameters follow the RosinRammler distribution function with a finite number of diameters. The effects of drag, thermal expansion, transient vaporization, and heat transfer by convection and radiation to the droplets and to the chamber walls were considered. The influences of chamber pressure, equivalence ratio, initial gas temperature, number of size classes, Sauter mean diameter, and parameters of the RosinRammler distributions on vaporization lengths of droplets are analyzed. Profiles of normalized diameters, temperatures, velocities, heat losses, vaporization rates, and other flow properties along the chamber are described.