Techniques that facilitate hybrid modeling for a device under test associated with a cooling system (e.g., a two-phase cooling system) are provided. In one example, information indicative of a first model of a device under test associated with a cooling system is determined. Second information indicative of constraints that define values for an operational quantity related to the cooling system is also determined. Information indicative of a second model for the device under test is generated based on the information indicative of the first model and the second information indicative of the one or more constraints. In an aspect, a first simulation process is performed to determine first thermal properties for a first simulation domain associated with the device under test. In another aspect, a second simulation process is performed to determine second thermal properties for a second simulation domain associated with the device under test.