Emerson Dilay

Notional all-electric ship systems integration thermal simulation and visualization

This work presents a simplified mathematical model for fast visualization and thermal simulation of complex and integrated energy systems that is capable of providing quick responses during system design. The tool allows for the determination of the resulting whole system temperature and relative humidity distribution. For that, the simplified physical model combines principles of classical thermodynamics and heat transfer, resulting in a system of three-dimensional (3D) differential equations that are discretized in space using a 3D cell-centered finite volume scheme. As an example of a complex and integrated system analysis, 3D simulations are performed in order to determine the temperature and relative humidity distributions inside an all-electric ship for a baseline medium voltage direct current power system architecture, under different operating conditions. A relatively coarse mesh was used (9410 volume elements) to obtain converged results for a large computational domain (185m×24m×34m) containing diverse equipment. The largest computational time required for obtaining results was 560 s, that is, less than 10 min. Therefore, after experimental validation for a particular system, it is reasonable to state that the model could be used as an efficient tool for complex and integrated systems thermal design, control and optimization.

Volume element model mesh generation strategy and its application in ship thermal analysis

We present a hexahedral mesh generation strategy for the volume element model.The proposed mesh generation strategy is applied in ship thermal analysis.Highly accurate representations of the ship geometry can be achieved.Plausible ship thermal solutions are obtained using a coarse independent mesh.The strategy enhances the overall computational efficiency of the VEM. This paper introduces a mesh generation strategy devised and implemented for the volume element model (VEM), and elaborates key contributions of the strategy in enhancing the VEM as a prominent tool in ship thermal modeling and simulation. The VEM mesh generation strategy employs ray crossings and ray- triangle intersection algorithms developed in previous studies, and constructs sufficiently accurate geometric representations of the whole ship within permissible time frame using hexahedral meshes. In addition, this work demonstrates the strategys practicality in thermal analysis of a notional all-electric ship, which is characterized by intricate structures and multiple internal components, i.e., thermal loads. Ship thermal solutions obtained in this assessment verify the proposed mesh generation strategys ability to improve the overall computational efficiency of the VEM, by allowing it to obtain plausible thermal solutions with respect to time and space using a coarse independent mesh.

Thermal management aspects of all-electric ships

This paper summarizes our current efforts on thermal management aspects of all-electric ships, including the analysis of incorporating combined cycle power plants, a study of thermal management strategies for the reduction of weight, the use of thermal anticipation strategies to handle dynamic loads, the thermal modeling and characterization of power electronic building blocks, and the system-level transient simulation of ship thermal loads.