Selection of fluid velocity in heat exchanger

The velocity of fluid not only directly affects the coefficient of convective heat transfer, but also relates to the thermal resistance of fouling, thus affecting the total coefficient of heat transfer Especially for the granular materials which are easy to deposit such as mixed sand, the low flow rate may cause the pipeline to be blocked, which will seriously affect the use group of the equipment and increase the flow rate, which will significantly increase the fluid resistance According to the experience, some commonly used flow rate ranges in industry are listed as follows for reference: the flow rate of fluid types commonly used in tubular heat exchanger, the flow rate of general fluid in M / S tube side and shell side is 0.5 ～ 30.2 ～ 1.5, and the scale forming fluid is more than 1 > 0.5, and the gas is more than 5 ～ 30 Flow rate range of different viscosity liquid in 3-15 shell and tube heat exchanger liquid viscosity PAS Zui large flow rate M / s > 1.5 (> 1500) 0.60.5-1.5 (1500-500) 0.750.5-0.1 (500-100) 1.10.1-0.035 (100-35) 1.51.82.4 Safety allowable speed of flammable and explosive liquid name of liquid safety allowable speed, M / s ether, < 1 methanol, ethanol, cold oil < 2-3 acetone < 10