Prediction of Duct Fitting Losses by Numerical Analysis

This project presents a computational analysis of the flow and pressure within given HVAC duct fittings by ASHRAE. The objective of the project was to determine the applicability of using commercially available Computational Fluid Dynamics (CFD) analytical tools to calculate representative fitting loss coefficients. Pressure loss data for the following fittings from the ASHRAE Duct Fitting Database for the flat oval straight body lateral, diverging flow were used for comparison purpose to evaluate the validity both data and CFD data. Further laboratory tests are intended to evaluate discrepancies. 

The ASHRAE Experimental Data was compared with the Numerical Solution for the determination of loss coefficients in test fitting for different flow rates, turbulent models and different mesh sizes. For the determination of Cs (main loss coefficient) and Cb (branch loss coefficient) both Standard k-ε and SST k-ω models are reasonably accurate but the precision obtained in SST k-ω model is excessively superior when compared with the Standard k-ε model.

Numerical Simulation Results