An Experimental Transient Response of a Heat Exchanger with the Al2O3/Water Nanofluid Mass Flow and Temperature Step Variations

• Published in: Heat transfer engineering 2021, Vol.42 (12), p.1002-1023
• Main Authors: Fotowat, Shahram, Askar, Serena, Fartaj, Amir
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Cross flow; Empirical analysis; Flow velocity; Heat balance; Heat exchangers; Mass flow; Nanofluids; Parameters; Performance enhancement; Process controls; Response time; Thermodynamic properties; Transient response
• ISSN: 0145-7632; 1521-0537
• DOI: 10.1080/01457632.2020.1766249

Experimental study on using nanofluid in a cross-flow minichannel heat exchanger (MICHX) to investigate its transient behavior was completed. Step changes of temperature and flow rate in the hot liquid were applied and the dynamic performance of the heat exchanger was analyzed. Results of nanofluid were compared to water and demonstrate an enhancement of 19% in heat transfer when using 2.5 wt% concentration Al 2 O 3 /water nanofluid. Parameters such as the transient effectiveness, heat balance, response time, and outlet temperatures of both liquid and air were also studied. The empirical correlations are developed for the temperature and mass flow step variations in a MICHX to predict the hot fluid outlet temperature in the dimensionless parameters. Nanofluid showed shorter response time for temperature and mass flow step changes compared to water. The outcome of this work is of interest to designers for process control, thermal testing, characterization, and performance enhancement of compact heat exchangers.