Title of Paper:Experimental research on the effects of fluid and heater on thermal stratification of liquefied gas

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Date of Publication:2013-10-01

Journal:EXPERIMENTAL THERMAL AND FLUID SCIENCE

Included Journals:SCIE、EI、Scopus

Volume:50

Page Number:29-36

ISSN No.:0894-1777

Key Words:Liquefied gas tank; Natural convection; Nucleate boiling; Thermal stratification

Abstract:The thermal stratification of liquefied gas influences the equipment safety. To find the factors and principles governing the thermal stratification, a device was set up to simulate the thermal response of a liquefied gas tank. A small steel vessel was used to simulate the tank, and two working fluids were used: water and R22. The heating region and liquid level were precisely adjusted in the tests to simulate different accident conditions. The experimental results showed saturation pressure of the working fluid affected the thermal stratification when the liquid wall was heated solely. For the case the liquid and vapor wall were heated together, evident thermal stratifications formed both in R22 and water tests. The degree and duration of thermal stratification are affected by the intensity of heat loading on the surface liquid. It is concluded that nucleate boiling in the lower liquid has great power to eliminate the thermal stratification. When the nucleate boiling is suppressed by hydrostatic pressure or saturation pressure of the warm surface liquid, the thermal stratification can form and maintain by natural convection. The stratifying process can be explained by a natural convection model. (c) 2013 Elsevier Inc. All rights reserved.