Numerical study on thermal performance of a BOG heat exchanger in the inclined condition

Abstract

This paper presents a numerical investigation of the inclination effect on the thermal performance of a tubular heat exchanger, which is utilized to extract the cold exergy from boiled-off gas (BOG). The finite volume computational fluid dynamics method and a k–ω-based shear stress transport model were used to simulate the fluid flow and heat transfer process. The simulation model has been validated by the engineering specification data from its supplier. To study the inclination effect on the heat exchanger, it has been simulated in two inclination planes and under different mass flow conditions. The result reveals that in the longitudinal inclination, the outlet temperature of both fluids changes in a linear relation with the inclination angle in a high mass flow condition. Reducing the mass flow would dramatically enhance the sensitivity of inclination. The largest temperature shift is 21.32 K, appearing in the tube side with a −30° inclination angle. However, the thermal performance is more stable in radial inclination, particularly in the high mass flow condition, and the temperature shifts of the shell and tube fluid are only 0.13 K and 0.31 K, respectively. Therefore, it is recommended to place the longitudinal direction of the heat exchanger on the normal position of the inclination plane and work at a high mass flowrate to weaken the inclination effect.