Views:1 Author:Site Editor Publish Time: 2020-04-22 Origin:Site
Many factories are now using more and more plate heat exchangers, but few people say that the resistance of plate heat exchangers, so today I will give a brief introduction to the majority of users, hoping to help everyone. Let's take a look.
1. Adopt hot mixing board
The geometrical structure of the corrugation on both sides of the plate of the hot mixing plate is the same. According to the angle of the herringbone corrugation, the plate is divided into a hard plate (H) and a soft plate (L). The angle (generally about 120 degrees) is greater than 90.
2. Adopting asymmetrical plate heat exchanger
The symmetrical plate heat exchanger is composed of plates with the same geometric structure of the corrugation on both sides of the plate, and forms a plate heat exchanger with equal cross-sectional areas of cold and hot runners.
According to the heat transfer characteristics and pressure drop requirements of cold and hot fluids, asymmetrical (unequal cross-sectional area) plate heat exchangers change the geometric structure of the two sides of the plates to form plate heat exchangers with different cross-sectional areas of cold and hot runners. The diameter of the corner hole on the side of the wide channel is larger.
The heat transfer coefficient of the asymmetrical plate heat exchanger drops slightly, and the pressure drop decreases greatly.
When the flow of cold and hot medium is relatively large, the use of an asymmetric single process can reduce the plate area by 15% to 30% compared with a symmetric single process heat exchanger.
When the flow of cold and hot medium is relatively large, a bypass pipe can be installed at the inlet and outlet of the heat exchanger on the side of large flow to reduce the flow into the heat exchanger and reduce the resistance.
In order to facilitate adjustment, a regulating valve should be installed on the bypass pipe. This method should adopt a counter-current arrangement to make the temperature of the cold medium out of the heat exchanger higher, and ensure that the temperature of the cold medium after the heat exchanger merges can meet the design requirements.
The advantage of setting the heat exchanger bypass tube is to ensure that the heat exchanger has a higher heat transfer coefficient, reduce the resistance of the heat exchanger, and the disadvantages are slightly more complicated to adjust.
4. The use of multi-process combination
Multi-flow combination arrangement is adopted, and more flows are adopted on the small flow side to increase the flow rate and obtain a higher heat transfer coefficient.
Less flow is used on the large flow side to reduce heat exchanger resistance.
Multi-flow combination appears mixed flow pattern, the average heat transfer temperature difference is slightly lower.
The disadvantage of using multi-process combination is that the fixed end plate and movable end plate of the plate heat exchanger both take over, and the workload is large during maintenance.