How to improve heat exchange coefficiency ?

                         How to improve the heat transfer efficiency of the heat exchanger?

A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid, also known as a heat exchanger. Heat exchangers play an important role in chemical, petroleum, power, food and many other industrial productions. In chemical production, heat exchangers can be used as heaters, coolers, condensers, evaporators and reboilers, etc., and are widely used . So what are the ways to improve heat transfer efficiency?
 
1. Improve the surface heat transfer coefficient of the tubing or plate
 
Because the corrugation of the plate heat exchanger can make the fluid turbulent at a small flow rate (Reynolds number - 150), it can obtain a higher surface heat transfer coefficient, the surface heat transfer coefficient and the geometric structure of the plate corrugation and the medium related to the flow state. The waveform of the plate includes herringbone, straight, spherical and so on. After years of research and experiments, it was found that the herringbone plate with a triangular corrugated cross-section (sinusoidal surface has a large heat transfer coefficient, a small pressure drop, and uniform stress distribution under pressure, but is difficult to process?) has a higher surface transfer rate. The thermal coefficient, and the larger the included angle of the corrugation, the higher the flow rate of the medium in the flow channel between the plates, and the larger the surface heat transfer coefficient.
 
2. Reduce the thermal resistance of the dirt layer
 
The key to reducing the thermal resistance of the fouling layer of the heat exchanger is to prevent fouling of the tubes or plates. When the scale thickness of the plate is 1 mm, the heat transfer coefficient decreases by about 10%. Therefore, attention must be paid to monitoring the water quality on both the cold and hot sides of the heat exchanger to prevent scaling of the plates and prevent impurities in the water from adhering to the plates. In order to prevent water theft and corrosion of steel parts, some heating units add chemicals to the heating medium, so attention must be paid to water quality and viscous agents that cause sundries to contaminate the heat exchanger plates. If there is sticky debris in the water, it should be treated with a filter. When choosing a medicament, it is advisable to choose a non-sticky medicament.
 
3. Choose tubes or plates with high thermal conductivity
 
Plate material can choose austenitic stainless steel, titanium alloy, copper alloy, etc. Stainless steel has good thermal conductivity, the thermal conductivity is about 14.4 W/(m•K), high strength, good stamping performance, not easy to be oxidized, and the price is lower than titanium alloy and copper alloy. It is often used in heating engineering, but its chlorine resistance The ability of ion corrosion is poor.

Keywords: heat exchanger, heat exchanger, heater, cooler, condenser