Flow-Thermal-Strength Analysis of the Finned Tube Heat Exchanger Operation

Abstract

Ensuring the safety and adequate service life of thermal power equipment, in addition to the need to maintain the required operating parameters, are among the most important issues related to the heat exchanger operation. This also applies to heat exchangers with extended surfaces, which are usually achieved by finned tubes. They are typically used where heat is exchanged between working fluids characterized by quite different properties, such as gas-water or air-coolant fluids. The high parameters of these fluids (temperature, pressure), occasionally their aggressiveness, and often the salts they contain, causing fouling of surfaces, can be the cause of failures. Among the most common are tube failures, which can lead to severe consequences. The developed methodology of coupled flow-thermal and strength analysis was used in exemplary calculations for a two-pass, two-row combustion gas - water heat exchanger with finned elliptical tubes. The reason for choosing such a design, was the fact of having failure data for two similar designs. This allowed verification of the correct operation of the developed methodology and redesign the heat exchanger manifold to ensure better flow distribution in a tubular space and better stress distribution.