Numerical Investigation into the Two-Phase Convective Heat Transfer within the Hold of an Oil Tanker Subjected to a Rolling Motion

Guojun Yu,Yanting Geng,Sheng Jia

doi:10.3390/jmse7040094

Abstract

A crude oil tanker usually encounters a rolling motion during sea transportation, which leads to rotational movement and sometimes a sloshing of the liquid hold. This rolling-induced body motion seriously affects the thermal and hydraulic behavior of the liquid hold, which then affects the heating process and heat preservation of the tanker. Clarification of the involved thermal and hydraulic characteristics is the basic requirement for establishment of a scientific heating scheme and heat preservation method. A two-phase 3D model considering the free liquid surface and non-Newtonian behavior of the fluid was established for the thermal calculation of the liquid holds in oil tankers. The thermal and hydraulic characteristics of the liquid hold were investigated under different combinations of dimensionless parameters, and the combined effect of rolling and fluid non-Newtonian behavior was investigated. It was found that rolling intensifies the heat transfer based on the combination of the Richardson number (Ri) and the rotation-strength number (ω*), and non-Newtonian behavior of the fluid effectively affects the heat transfer in a rolling motion. This research is expected to provide a reference for design and optimization of the heating and heat preservation method for oil tanker operation.

Highlights

Tanker transportation is one of the most important ways for crude oil transportation, especially during international crude oil trade
The thermal-hydraulic behavior of crude oil in ocean conditions is much more complicated than that in static conditions, since the flow and heat transfer is influenced by the motion-induced additional forces, such as centrifugal force, Euler force, Coriolis force, and buoyancy forces induced by these forces, in addition to the forces for static cases
The effects of Richardson number (Ri), ∗, and non-Newtonian behavior on the thermal-hydraulic process of crude oil subjected to a rolling motion were investigated numerically

Summary

Introduction

Tanker transportation is one of the most important ways for crude oil transportation, especially during international crude oil trade. Some high-pour point or high-viscosity crude oil requires heating during transportation to ensure good flow ability for flexible offloading. This heating process consumes large amounts of energy, and a scientific heating scheme bears great potential to save energy. The motion of the tanker during sea transportation includes oscillations of six degrees of freedom, such as linear motions, including heaving, swaying, and surging, and rotational motions, including rolling, pitching, and yawing. Among these movements, the rolling motion has a more important influence on the thermal-hydraulic behavior [1]. Only the rolling motion is investigated in this research

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