An enhanced thermal model for cryogenic tanks

This work studies heat transfer in a cryogenic tank, in order to estimate the heat infiltration rate as well as the required thermal insulation thickness needed to fulfill the boil off ratio. It addresses some general recommendation about thermal insulation thickness. Design calculations to actually get thermal insulation thickness are presented in another paper. The present research work establishes analytically temperature distributions in outer tank walls due to varying outside conditions. A simple formula that can be used by designers has been obtained that closely approximates the detailed analytical solution developed in the present work. Comparison shows that this approximate estimate is a very close and slightly more conservative than the detailed analytical solution. Moreover, it proves that uniform heat flux density gives the best distribution of insulation over different tank part.