For them who work in chemical processes such as a chemical engineering, maybe know what a heat exchanger is, but how about the others? Do you know what is heat exchanger? A heat exchanger is a kind of device/machine used for exchanging heat between two flowing streams/fluids (can be liquids or gases or mixed of them). The streams flow through the exchanger separated by a conducting wall (usually made from iron or other kind of metal) so that the heat can flow from the hotter stream to the colder stream.
There are several types of heat exchanger like the shell-and-tube heat, the parallel-plate exchanger, etc. But the simplest type is the concentric-tube heat exchanger which consists of one pipe surrounding another. In this case, one fluid flows through the annular space outside the inner pipe and the heat conducting through the pipe wall. Different from the one we have talking about, in a parallel-plate exchanger, the cold and hot fluids flow through alternate spaces between plates.
Based on the direction of the fluid flow, there are two kinds of heat exchanger, co-current or parallel flow and countercurrent flow. In the first one, both fluids entering the exchanger on the same end and flowing in the same direction along the exchanger, the temperature difference between two fluids decreases during the process. in the second one, each fluid enters the exchanger on the counter flow so that the temperature difference doesn't vary as dramatically as in the first one. Furthermore, we can conclude that in countercurrent flow, the outlet of the cold fluid maybe hotter than the outlet of the hot fluid.
There are several types of heat exchanger like the shell-and-tube heat, the parallel-plate exchanger, etc. But the simplest type is the concentric-tube heat exchanger which consists of one pipe surrounding another. In this case, one fluid flows through the annular space outside the inner pipe and the heat conducting through the pipe wall. Different from the one we have talking about, in a parallel-plate exchanger, the cold and hot fluids flow through alternate spaces between plates.
Based on the direction of the fluid flow, there are two kinds of heat exchanger, co-current or parallel flow and countercurrent flow. In the first one, both fluids entering the exchanger on the same end and flowing in the same direction along the exchanger, the temperature difference between two fluids decreases during the process. in the second one, each fluid enters the exchanger on the counter flow so that the temperature difference doesn't vary as dramatically as in the first one. Furthermore, we can conclude that in countercurrent flow, the outlet of the cold fluid maybe hotter than the outlet of the hot fluid.
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