Thermal Performance Prediction for Air Flow in a Wavy Corrugated Duct at Steady-State Constant Heat Flux Mode and Early Stages of Turbulent Flow Conditions

Abstract

The present work represents an attempt to formulate the air heat transfer performance exhibited from a wavy corrugated duct in the form of simplified correlations at constant heat flux. The correlations are empirical formulae intended to be applied for a corrugation wavelength to amplitude ratio (λ/a) of (5.7-12.6) with (0°) phase shift angle at corrugation plate angles of (54.5°), (45°), (38°), and (32.5°). The main stream air flow Reynolds number domain through the corrugated duct was bounded by (1.85×10 3) to (3.9×10 3). Four simple correlations for the heat transfer coefficient enhancement factor, corrugated duct heat transfer coefficient, Stanton number and Nusselt number were developed by the implementation of the Buckingham-pi theorem. These correlations were in terms of the duct corrugation characteristics, flow operating conditions and exerted heat flux. The deviation of the predicted data for the heat transfer coefficient enhancement factor was within a scatter of (± 10) %. The corrugated duct Stanton number, Nusselt number and heat transfer coefficient were correlated with accuracy margin of (± 20) % of the measured experimental data.