What is counter flow heat exchanger?
Counter flow heat exchanger means that Accordin the hot fluid fkow from up to down and the cold fluid flows from upper to down arrangement.
In the heat exchanger, the average linear temperature difference of heat transfer marks the amount of heat transfer, and the heat transfer formula Q=KA(ΔTm) knows that the larger ΔTm, the larger heat transfer Q.In the countercurrent, downstream, cross-flow heat exchanger, the average temperature difference of the countercurrent heat exchanger is the largest, so the heat exchanger is often in the form of counterflow without special circumstances.
In the case of countercurrent, the outlet temperature of the cold fluid can be higher than the outlet temperature of the hot fluid, while in the downstream, the outlet temperature of the hot fluid is always lower than the outlet temperature of the cold fluid, so in the case of countercurrent, the temperature difference between the hot and cold is larger, that is, the average logarithmic temperature difference is larger than the downstream flow. Therefore, when the heat exchange area is the same, the countercurrent can transfer more heat.