A correction factor for one-dimensional heat transfer coefficients around a horizontal tube in a fluidized bed

A stainless steel heat transfer tube was placed into a cold bubbling fluidized bed and temperature data at points on the tube circumference were captured by using miniature thermocouples. These instantaneously measured boundary temperatures were used to evaluate one-dimensional (1D) and two-dimensional (2D) heat transfer coefficients by solving transient 1D and 2D heat conduction equations across the tube numerically. In previous research, comparison between 1D and 2D transient, as well as average, heat transfer coefficients were demonstrated. Due to the significant difference between 1D and 2D heat transfer coefficients, a need for a correction factor was emphasized. In this research, further analysis is accomplished to show the physical nature of this difference. The studies showed that the differences between 1D and 2D heat transfer coefficients around the horizontal heat transfer tube originated largely from an approximately steady state heat flux produced by nonuniform surface temperatures. Based on an analytical study, a correction factor was developed to correct 1D heat transfer coefficients around the heat transfer tube in bubbling fluidized bed.