Calculation of heat flow in gas carrier structure based on analytical methods of heat exchange theory

Abstract

The aims of the article is to describe and demonstrate the practical application of analytical heat flow calculation in ship hull and thermal insulation of liquefied gas carriers. Numerical parameters describing the heat flow are used to calculate the amount of boil-off gas evaporating from liquefied gas surface in tank. Also, such numerical parameters are used to define the design temperature of hull structures adjacent to gas containment system. The article gives the results of test heat flow calculations for three ships. Two of the ships are equipped with membrane containment system and have the total cargo capacity of 361000 m3 and 172000 m3 , respectively. The third test ship is equipped with two type C tanks of 2900 m3 capacity each. The calculations corresponding to the standard environment conditions as per industry normative documents have been performed. Reliability of the results, as well as the mathematical model itself, has been checked. Case studies have been done to assess the influence of external conditions to heat flow parameters, both numerically and qualitatively. The results given in the article may be used to improve the requirements of normative documents, and in practical cargo containment system design.