Thermo-fluid performance of axially perforated multiple rectangular flow deflector-type baffle plate in an tubular heat exchanger

Abstract

The study investigated an unconventional heat exchanger design that utilizes swirling airflow to enhance heat transfer over heated tubes. This innovative system incorporates a perforated round baffle plate, accompanied by multiple rectangular air deflectors oriented in opposite directions at varying inclination angles. These deflectors are symmetrically arranged at different pitch ratios alongside consistently spaced tubes forming a circular configuration, all subject to a uniform heat flux. Enclosed within a circular duct with longitudinal airflow, the combined baffle plate and tube assembly bring forth efficient heat transfer. The air-side turbulence intensified by the deflectors induces a chaotic motion, contributing to enhanced surface heat transfer. Each baffle plate has twelve opposite-oriented deflectors, resulting in opposing swirl flows that further promote flow recirculation and augment surface heat transfer. The performance of this heat exchanger was evaluated by considering different pitch ratios and inclination angles across a Reynolds number range of 16000-30000. The findings demonstrate that the heat exchanger with rectangular flow deflectors on the baffle plate exhibits significant improvements in thermo-fluid performance. Notably, an average enhancement of 1.88 was observed at an inclination angle of 50 degrees and a pitch ratio of 1.2 when compared to an exchanger without baffle plates, emphasizing the considerable impact of these design aspects.