Compact binary merger simulations in numerical relativity The era of Gravitational Waves Astronomy was launched after the success of the first observation run of the LIGO Scientific Collaboration and the VIRGO Collaboration. The large laser interferometers incredible achievement prompted the need of extensive studies in the field of compact astrophysical objects such as Black Holes and Neutron Stars. Today seven years after this event the field of study underwent a notable expansion corroborated by the detection of a signal coming from a Binary Neutron Star merger together with its electro magnetic counterpart and more recently by the first detections of signals coming from mixed compact binaries i.e. Black Hole Neutron Star binaries. In this thesis work we span our attention across different aspects of compact objects mergers including the inclusion of new physics into the already performing numerical relativity code BAM and the study of specific systems of compact objects. We first explore the treatment of neutrinos in case of Binary Neutron Star mergers and a tool to identify and further analyze regions containing trapped neutrinos in the hot remnant of such mergers. Neutrinos play in fact a key role into the rapid processes that characterize the formation of elements in the dynamical ejecta expelled during these catastrophic events. In the following we explore a variety of configurations of mixed compact binary systems. After the development of the new ID code Elliptica and the steps taken to verify its accuracy we make use of its capability to evolve sets of physical system with various properties. Exploring the space of parameters we study different spin configurations and magnitudes of single objects and their effects on the merger dynamics.