The influence of airflow on the effectiveness of rotary heat exchangers operating under high-speed rotor conditions

¹ Wrocław University of Science and Technology, Faculty of Environmental Engineering, Department of Air Conditioning, Heating, Gas Engineering and Air Protection, ul. Norwida 4/6, 50-373 Wrocław, Poland
² Saint-Petersburg State University of Architecture and Civil Engineering, Department of Mathematics, 2-nd Krasnoarmeiskaya st. 4, 190005 Saint-Petersburg, Russian Federation

^* Corresponding author: paulina.kanas@pwr.edu.pl

Abstract

The paper presents an analysis of heat and mass transfer processes occurring inside the rotary heat exchanger operating under high-speed rotor conditions for different values of the airflow rate. For this purpose the original mathematical α-model was used. Conducted computer simulations allowed to determine the influence of Number of Transfer Units (NTU) of airflow on the temperature effectiveness as well as on the distribution of different active heat and mass transfer zones: “dry”, “wet” and “frost”. It was found that the increase of the values of NTU strictly affects the increase of the effectiveness of heat recovery. Another issue emerging from this study is the fact that in the certain range of low values of NTU there is no “dry” area created. It was established that at low values of NTU (NTU≈1) “frost” area extremum and sharp drop in the “frost” area accumulation are observed.