Hybrid numerical simulation of large-scale gas-fired tubular heat exchangers

Abstract

This article presents a hybrid computational fluid dynamics (CFD) modeling approach to the large-scale gas-fired heat exchanger. As the full-grid simulation on this heat exchanger requires impractical computational cost, a simplified “1D + 2D + 3D” hybrid CFD model is developed to reduce the computational cost and make the simulation doable on the common workstations. In this model, the air side is simulated by the 3D CFD model with the porous media simplification on tube bundles. The gas side is modeled by a 2D axisymmetric combustion model and a 1D duct model, which is implemented by the user-defined function (UDF) method. Furthermore, the “1D + 2D” gas-side models are coupled with the “3D” air-side model, while the UDF is coded for updating the boundary conditions on both sides during iterations. Reasonable agreement is achieved between the simulations and the measured results of pressure drop, overall heat transfer rate, air temperature rise, and tube wall temperature distributions.

Acknowledgments

Dr. Junjie Ji is a Senior Engineer. Dr. Yuling Shi is a Senior Staff Engineer. Chunlu Zhang is a Professor.