Break | AIChE


Hydrazine and its derivatives are used as rocket fuels in satellites, but hydrazine’s high toxicity and reactivity make laboratory experiments dangerous. Computer simulations can be used to model operations such as refueling, storage, and normal rocket combustion, but without an accurate thermodynamic model, these simulations will not give meaningful results. Currently, hydrazine does not have an accurate model for the Vapor-Liquid Equilibrium (VLE) near the critical point. The key to a better thermodynamic model is an accurate force field. Using Density Functional Theory (DFT) with a coupled cluster functional with single and double excitations (CCSD), a new force field will be constructed with highly accurate parameters. Current force field parameters for hydrazine do exist, but the functionals used in previous works do not hold the level of accuracy that the CCSD functional can provide. A CCSD functional accounts for the energy all of the electrons in the system and not just valence electrons. DFT calculations were used to obtain bonding coefficients for a classical potential using a curve fitting method. The resulting equilibrium bond lengths are shorter than those of past works, which makes the hydrazine molecule smaller. This may affect the phase densities in the VLE calculations. With the newly built force field, the focus of the project can be returned to the VLE predictions using Monte Carlo simulations.