Computational Fluid Dynamics Simulation of Ljungstrom Rotary Preheater in Steam Power Plant for Leakage Assessment Using Porous Media Approach

Ljungstrom rotary air preheaters are applied at power plants to use the waste energy. In this study, by applying the CFD model, mass, momentum, and energy equations in a porous media are solved using moving reference frame (MRF) and the leakage rate content evaluated. The validation of numerical simulation proved by comparison of the numerical results and experimental data. In this study, the effect of different operational conditions such as matrix rotation speed, plate’s material, inlet fluid preheating on the exchanger performance investigated. Also, the value of axial leakage and radial leakage estimated and the effect of using different seal types on leakage rates investigated. Numerical results show increasing the rotational speed up to certain limit, using materials with low thermal diffusivity, and preheating the inlet fluid considering the economical issues, developed the exchanger performance. Leakage estimation results show the radial leakage is the main leakage in the Ljungstrom and using double-seal and triple-seal can reduce the leakage rates considerably.