Design method of average temperature difference method for plate heat exchanger

Design method of average temperature difference method for plate heat exchanger

1. Calculate the unknown temperature or flow, calculate the unknown temperature or flow through the heat balance equation, and also calculate the heat load Q.

2. Select the appropriate plate model, according to the heat exchange and flow, select the appropriate plate model.

The plate type shall be selected according to the specific working conditions. When the flow rate is large and the pressure drop is low, the plate type with small resistance should be selected; otherwise, the plate type with slightly larger resistance coefficient can be selected.

3. The heat exchange area is estimated, and the approximate heat exchange area is calculated according to the heat exchange.

4. Choose the number of flow and channel, preliminarily choose the number of cold and hot fluid flow and channel, and then calculate the flow rate.

5. Find the average temperature difference.

6. In order to calculate the convective heat transfer coefficient and the total heat transfer coefficient, the convective heat transfer coefficients of cold and hot fluids are calculated respectively.

7. Calculate the necessary heat exchange area.

8. Check the heat exchange area again.

9. To check the pressure drop, the allowable pressure drop is often a constraint factor in the design of plate heat exchanger. However, efficient design always requires sufficient allowable pressure drop. If the relationship among heat exchange load, flow and allowable pressure drop can not be coordinated no matter how to change the flow arrangement, only an inefficient design scheme can be made. If in the design, can not get the satisfactory design plan all the time, then may consider to change the board type.

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