Introduction

The CFD analysis of a Gas-Gas heater was undertaken to gain insights into the velocity distribution inside the Air Preheater (APH) module. The primary objectives were to understand the flow uniformity at the APH Inlet and Outlet, identify section-wise pressure drops across the system, and make design recommendations as necessary.

Challenges

The CFD analysis of the Gas-Gas Heater encountered challenges, including minor flow recirculation due to sudden contractions, low total pressure in localized regions affecting efficiency, gradual temperature decreases in the GGH module indicating heat loss, and the struggle to achieve uniform velocity distribution across the APH volume, prompting a search for improvement.

Solution

To enhance the Gas-Gas Heater’s performance, porous resistances were introduced in the APH volume to achieve a more uniform flow profile at the inlet. Modified flow guiding vanes addressed non-uniform flow, reducing recirculation downstream. The Flow Uniformity Index served as a metric to quantify improvements, with a particular emphasis on enhancing performance at the APH outlet.

Benefits

The CFD simulation of the Gas-Gas Heater provided valuable insights, enabling the identification and resolution of challenges to enhance system efficiency and performance. The implementation of porous resistances and modified flow guiding vanes successfully improved flow uniformity, reduced recirculation, and optimized pressure drops across the system.