Three-dimensional simulation of rotary air preheater in steam power plant

• Three-dimensional thermal simulation of full-scale rotary air preheater is presented.
• Variation of isothermal lines in the air preheater are shown.
• Effect of separator plate on the temperature distribution is restricted to center of the matrix.
• Rotational speed of matrix has important role in the performance of preheater until certain limit.

In this study, thermal behavior of a full-scale rotary air preheater is investigated using three-dimensional approach and treating preheater matrix as a porous media. Mass, momentum and energy equations are solved using moving reference frame (MRF) to incorporate the effect of rotational speed of the matrix. Temperature distributions of the matrix at different conditions have been presented and the effect of essential parameters such as rotational speed of the matrix, fluid mass flow, matrix material and temperature of inlet air on the performance of preheater have been discussed. Numerical results which are confirmed by experimental data show the significant effect of rotational speed, separator plate, fluid flow rate on the performance and temperature distribution of preheater. Increasing the rotational speed of the air heater increases the efficiency up to certain limit, after which it does not significantly change. It was also found that the effect of material change on the efficiency is very limited.