AC-20 Side Blockage Effects on Performance of Forced-draft Air-cooled Heat Exchangers

S. Haq

This report details a numerical study investigating the effects of blockages on the performance of an air-cooled heat exchanger. A high-fidelity computational fluid dynamics (CFD) model of HTRI’s Air-cooled Unit (ACU) is simulated and calibrated using experimental data from the unit. The validated CFD model is used to simulate five arrangements of air-intake blockages at constant fan RPM. As the percentage of open area around the ACU reduces, the airflow through the bundle reduces. The amount of flow through each fan depends on the location of the fan in relation to the blockage. For extreme blockages, flow maldistribution between the two fans can be as high as 30% of the total flow rate. With severe airflow maldistribution at the bundle exit, average fan cell temperatures differed by as much as 10 K.