Numerical Method on Heat Transfer in Tri-sectional Regenerative Air Heater

According to the working mechanism of rotary air preheater,taking the metal heat-retaining element as a hypothesis fluid and assuming the unsteady heat transfer and mechanical motion of the metal heat-retaining element as a steady heat transfer process,the fluid dynamic and heat transfer differential(equations) and corresponding difference equations for rotary air preheater were founded by use of control(volume) method through theoretical analysis.The calculation process of the numerical method was given in detail.As an example,the thermal check calculation was carried out according to the practical operational parameters of a tri-sectional regenerative air heater with separated cold and hot sections of a 220 MW boiler unit.Results show that the numerical method is reasonable,and has fast convergence and reasonable calculation accuracy.The reasonable temperature distribution of the metal heat-retaining element,flue gas and air in the air preheater can be obtained.Checked by the practical operational parameters,the calculating results agree well with the parameters under design condition.