Investigation on the Use of Settling Means for Obtaining Uniform Airflow in a Fan Test Chamber

fan test chamber, based on multiple-nozzles method, provides useful data on the performance of axial and centrifugal fans, and it may also be used for evaluation of Ventilation Efficiency Ratio (VER) of these fans. In order to obtain reliable experimental data from a fan test chamber, it is important to ensure a substantially uniform airflow ahead of the measuring plane. This can be achieved by a settling means located upstream of the measuring plane. The purpose of the settling means is to absorb the kinetic energy of the upstream jet, and allow its normal expansion as if in an unconfined space. In this study, we have used numerical simulations to investigate the effect of combinations of screens on the airflow profile in a fan test chamber. The main variables considered in this simulation are; the open area ratios of screens with square mesh round wires, and the screens layout (screens arrangement). Three sets of the settling means, each combining three screens of different open area ratios have been evaluated. The combinations of screens studied have; 50-50-40%, 50-50-50% and 60-60-60% open area ratios. The results show that the settling means with 50-50-40% open area ratios combination, presents the optimum flow conditions at upstream of the measuring plane, used in the fan test chamber. The results of this analytical study have been used in the design and construction of a bed for testing of fans.

کلیدواژه ها:

Ventilation Efficiency Ratio ، Airflow measurement ، Airflow profile ، Settling means ، Screens ، Open area ratio