Experimental investigation of the effects of airflow nonuniformity on performance of a fin-and-tube heat exchanger

• The effects of airflow nonuniformity on heat exchanger performance are investigated.
• Airflow nonuniformity causes thermal effectiveness deterioration.
• Airflow nonuniformity causes pressure drop increase.
• The influence of the degree of airflow nonuniformity is discussed.
• The influence of orientation between airflow nonuniformity and circuitry is analyzed.

The effects of airflow nonuniformity on the thermal–hydraulic performance of a fin-and-tube heat exchanger were investigated experimentally. The test subject was a four-depth-row fin-and-tube heat exchanger with face split tube circuitry. Nonuniform inlet air distribution was generated by partially blocking the heat exchanger entrance cross-section. It was found that airflow nonuniformity causes thermal effectiveness deterioration and pressure drop increase. The size of effectiveness deterioration and pressure drop increase depend on the degree of airflow nonuniformity as well as on the orientation between airflow nonuniformity and tube-side fluid circuitry. For most of the observed nonuniform airflow profiles, which had low or moderate degrees of airflow nonuniformity, the effectiveness deterioration was between 5% and 10%, while the pressure drop increase was between 10% and 20%. For severely nonuniform airflow profiles the effectiveness deterioration was up to 30% and the pressure drop increase was up to 90%.