It is cheap to put fins to the heat transfer area but fins also increase fouling, especially in bio-process. The data obtained from the heat transfer experiment shows that the velocity of the cooling fluid is directly proportional to the overall transfer coefficient. As the cooling fluid velocity increases, the cooling fluid is able to dissipate heat more effectively. The data have shown that it is the case. Although increasing flow velocity can give more effective heat transfer, it may not be a good idea in some bio-process.
High velocity creates high shear stress in flow .
Some proteins' or cells' structures are very delicate. They cannot withhold such force and they will be destroyed. The whole batch can be ruined. Temperature gradient Temperature gradient is certainly a important part of heat transfer. It is the driving force for heat transfer.