Performance of Air-Cooled Heat Exchanger with Laminar, Transitional, and Turbulent Tube Flow

Dawid Taler, S. Grądziel, S. Łopata, T. Sobota, W. Zima
2018 MATEC Web of Conferences  
Some air-cooled heat exchangers, especially in air conditioning and heating installations, heat pumps, as well as car radiators, work in a wide range of loads when the liquid flow in the tubes can be laminar, transitional or turbulent. In this paper, a semi-empirical and empirical relationship for the Nusselt number on the liquid-side in the transitional and turbulent range was derived. The friction factor in the transition flow range w, trb w w, tre Re Re Re  was calculated by linear
more » ... ation between the values of the friction factor for w,trb Re 2,100  and w,tre Re 3,000  . Based on experimental data for a car radiator, empirical heat transfer relationships for the air and water-side were found by using the least squares method. The water temperature at the outlet of the heat exchanger was calculated using P-NTU (effectivenessnumber of transfer units) method. The heat flow rate from water to air was calculated as a function of the water flow rate to compare it with the experimental results. The theoretical and empirical correlation for the water-side Nusselt number developed in the paper were used when determining the heat flow rate. The calculation results agree very well with the results of the measurements.
doi:10.1051/matecconf/201824002012 fatcat:72mvlcachzctbchrvm5zoey3pm