Modeling and Simulation of the Thermal and Psychrometric Transient Response of All-Electric Ships,Internal Compartments and Cabinets

Abstract

We introduce a general computational model for all-electric ships and internal compartments (open and closed domains) that contain heat sources and sinks. A simplified physical model, which combines principles of classical thermodynamics and heat transfer, is developed and the resulting three-dimensional (3D) differential equations are discretized in space using a 3D cell-centered volume element scheme. The combination of the proposed simplified physical model with the adopted finite volume scheme for the numerical discretization of the differential equations is therefore called a volume element model (VEM). Two case studies are presented: a simulation of a whole ship at sea, and one of the ship's internal compartments (or cabinet). The proposed model was utilized to simulate numerically the steady-state responses of the systems in both cases. Of particular interest in the first case is the possibility of predicting the ship's thermal signature at sea. Mesh refinements were conducted to ensure the convergence of the numerical results. The converged mesh in both cases was relatively coarse (175 and 320 cells) and therefore the solutions were obtained with low computational time. Since accuracy and low computational time are combined, the model is shown to be efficient and could be used as a tool for simulation, design and optimization of thermal management of all-electric ships, internal compartments and cabinets. Finally, experiments are conducted in a test-bed facility to demonstrate, from simulated sea conditions, how to quantify the electric motors transient heat rejection to cooling water and the environment in a notional all-electric ship, with the objective of serving as known heat generation inputs to the mathematical model to simulate the transient thermal response of the entire ship and its compartments.