What kind of flow occurs in an exchanger when the liquids enter from one side and exit in the same direction?

In a heat exchanger where liquids enter from one side and exit in the same direction, the flow is characterized as parallel flow. In this configuration, both the hot and cold fluids move in the same direction as they pass through the heat exchanger, which allows for a continuous exchange of heat along the length of the exchanger.

This type of flow results in a temperature gradient that decreases as the fluids travel together, leading to a less effective heat transfer compared to counterflow arrangements. In a counterflow system, for example, the fluids flow in opposite directions, maximizing the temperature differential between the two streams and enhancing the overall efficiency of heat transfer.

Parallel flow is often simpler in design but can be less efficient for heat exchange, especially over long distances or for fluids with significantly different inlet temperatures. Understanding this setup is crucial for applications that involve heating or cooling processes where optimizing thermal efficiency is important.