# Multi-Domain Modeling and Analysis of Marine Steam Power System Based on Digital Twin
###### Abstract
The combination of multi-disciplinary modeling methods and digital twin technology can give full play to their advantages in modeling and simulation. At present, several scholars have carried out relevant research. [PERSON] put forward a model-driven method for the online monitoring and predictive maintenance of automobile braking system, established digital twin models of its key components using Ansys and the Modelica language, analyzed the signal response of the braking system under gear/mechanical failure, and laid a foundation for the subsequent diagnosis and prediction of the braking system [8]. [PERSON] developed the model library of an electrical power system based on the Modelica language, which includes a multi-fidelity, multi-scale battery, power electronics and an electrical propulsion system sub-library, and used this library to build the digital twin model of an electrical power system in the process of product development, aiming to reduce development costs and carry out status monitoring [9]. [PERSON] pointed out that the satellite communication station is a typical multi-disciplinary physical system, which is composed of six systems, including the antenna system, receiving system, transmitting system, communication system, control system and power supply system, through the demand analysis of the digital twin construction of satellite earth stations; the method of building a digital twin system of satellite communication equipment using MWorks multi-domain system modeling platform is proposed. Finally, the effectiveness and feasibility of the digital twin modeling method are verified [10]. [PERSON] et al. applied digital twin technology to the energy recovery devices in air conditioning systems. Based on the Modelica language, they developed their digital twin model to predict the behavior of the physical system. They communicated with the physical model through the Message Queuing Telemetry Transport (MQTT) interface to achieve the virtual reality mappingof the physical model and the digital twin model, which can improve the efficiency of energy recovery devices [11]. In order to monitor the operation status of the space station in real time, [PERSON] et al. established seven subsystem models of dynamics and control, energy, environmental and thermal control, propulsion, information, data management, and measurement and control of the core cabin, test cabin I and test cabin II of the space station based on the Modelica language and the MWorks system simulation platform, covering the general system, subsystems, and key stand-alone equipment, and conducted simulation analyses of the typical working conditions of subsystems, respectively. The functional mock up interface (FMI) standard was adopted to integrate the digital twin models of a single cabin, two cabin, one font and three cabin T-shaped system of a space station, analyze and verify the rendezvous and docking, transposition and other scenarios, and achieve the analysis and verification of the system level, all boundaries and all working conditions of the space station [12]. In a word, the thermal equipment of the marine steam power system is a typical and strong coupling complex system with complex composition and working conditions, and, with the traditional modeling method, it is difficult to satisfy the development requirements of digital and intelligent thermal equipment. In view of the advantages of multi-disciplinary modeling in the modeling of complex physical systems and the wide application of digital twin technology in equipment health management, this paper combines the ideas of multi-disciplinary modeling and modular modeling under the digital twin technology system to build a digital model of the main equipment and subsystems of the marine steam power system, and uses the Modelica language and the MWorks system simulation platform to build the digital model of the marine steam power system.