Pressure loss and fluid flow characteristics of square duct flow with T-junction

Abstract

The determination of energy losses caused by flow division at T-junctions is important in the design and analysis of industrial fluid transport systems. This experimental study addresses flow division through a 90° T-junction with a square cross section. On the basis of mean velocity at the main duct and the hydraulic diameter, the Reynolds number ranges from 1.3 × 103 to 2.0 × 104. The flow rate ratio (i.e., the ratio between the branch and main duct flow rates) is set between 0.2 to 0.8. Duct widths and heights are fixed at 10 mm in the main and branch ducts. Wall static pressure and loss coefficient are measured to quantify the energy loss. In order to investigate the relationship between fluid flow and pressure loss, velocity profiles are measured by particle image velocimetry. For laminar flow, the loss coefficient of the branch increases rapidly with increasing flow rate ratio because of a reverse flow from the main duct to the branch. For turbulent flow, the recirculation length in the main duct decreases compared to laminar flow. These experimental data provide empirical loss coefficient equations for T-junctions, which constitute useful tools for the determination of loss coefficients for T-junction.

Keywords

• square duct flow
• t-junction
• dividing flow
• loss coefficient
• piv