Experimental Investigation of the Flow Maldistribution Inside an Air-Cooled Heat Exchanger

Abstract

Flow maldistribution in heat exchanger tubes can significantly affect its performance. In this work, 16 tubes are connected between the inlet and the exit headers forming the heat exchanger. The feed nozzle is connected to the inlet header, and its connection point can be altered. The influences of inlet flow Reynolds number, nozzle diameter, number of nozzles and nozzle location on the flow maldistribution are experimentally investigated. Water is chosen to be the working fluid inside the heat exchanger set of tubes. At lower flow rates, the results showed that the flow Reynolds number has a significant effect on the flow maldistribution inside the heat exchanger set of tubes; however, at higher flow rates, this effect was insignificant. Locating the nozzle at the center of the inlet header resulted in about 25-30 % reduction in the standard deviation (STD) of the flow rate inside the tubes. Increasing the number of inlet nozzles resulted in an insignificant effect on the flow maldistribution. Increasing the nozzle diameter resulted in increased STD of the flow rate distribution among the tubes and pressure drop across the tubes at the considered heat exchanger geometry and water flow rate.