Naslov
The Effects of Airflow Nonuniformity on Fin-and-Tube Heat Exchangers: An Experimental Study

Autori
Blecich, Paolo ; Trp, Anica ; Lenić, Kristian ; Batista, Josip

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of the 14th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2019) / Meyer, Josua P. - Pretoria : American Society of Thermal and Fluids Engineers (ASTFE), 2019, 1416-1421

ISBN
978-1-77592-191-2

Skup
14th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2019)

Mjesto i datum
Wicklow, Irska, 22.07.2019. - 24.07.2019

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Experimental study ; fin-and-tube heat exchanger ; airflow nonuniformity ; thermal-hydraulic performance.

Sažetak
This paper presents an experimental study about the effects of airflow nonuniformity on the thermal and hydraulic performance of fin-and-tube heat exchangers. Two fin-and-tube heat exchangers were tested. The first was a three-depth-row heat exchanger with a total of 38 tubes in 7 tube circuits and a total air side heat transfer area of 40 m2. The second heat exchanger has 32 tubes in 6 circuits for a total air side heat transfer area of 27 m2. In both heat exchangers, two circuits have four-tube arrangement while the remaining circuits have six-tube arrangement. The two heat exchangers were tested inside an open wind tunnel and the fluid on the tube side was hot water. The heat exchangers were placed vertically inside the wind tunnel. Nonuniform distribution of inlet air velocity was generated by partial blocking the entrance cross section, inducing airflow nonuniformity on the heat exchange surfaces. Inlet and outlet air and water temperatures were measured using thermocouples while air flow velocities were measured with hot-wire anemometers. The air pressure drop across the heat exchangers was measured with differential pressure sensors. The experiments revealed that airflow nonuniformity causes thermal effectiveness deterioration and pressure drop increase, the size of which depends on the degree of airflow nonuniformity. It was found that fin-and-tube heat exchangers with unbalanced tube circuitry may lead to nonuniform outlet air temperatures, as a consequence of uneven tube-side flow resistance due to circuits with different number of tubes.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo, Temeljne tehničke znanosti

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