LAUSR

Abstract Plenum chambers are widely used in heating, ventilation, and air conditioning systems (HVAC) for homogeneous flow and pressure distribution. To date, scientific design methods and key parameters influencing chamber systems have not been determined for HVAC engineering applications. In this study, a single-path unlined rectangular plenum chamber is used to investigate interior flow characteristics in a confined space. An orthogonal experiment is conducted to identify the key influencing factors and evaluate their significance. Through the analysis of range and variance, the sectional dimensions (W × H) and length (L) of the chamber were found to be the most significant factors for structural design. A structural parametric optimisation method is proposed for the chamber system. The optimal cross-sectional aspect ratio of the plenum chamber (W/H) is determined as follows: when the cross-sectional velocity vchamber ≤ 1 m/s, W/H = 1/1; when vchamber > 1 m/s, the W/H should be as close as possible to 5/1, corresponding to a smaller pressure drop. The generalised velocity profiles in each cross-section are almost the same when the dimensionless length L/de ≥ 3, indicating that the inside “jet” entering the rectangular plenum chamber reaches fully developed flow. The threshold parameter for the optimal length of the chamber was obtained from the perspective of reducing energy consumption. Additionally, the interior flow characteristics of the chamber system were analysed with different configurations. This study provides first-hand data for optimising the structural design of a single-path plenum chamber in an HVAC system.