Vertical heat exchanger without liquid-liquid phase change
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Dear expert, I would like to ask: for a heat exchanger without liquid-liquid phase change, if a vertical design is used with the cold side having fluid flow from bottom to top within the shell side and the hot side having fluid flow from top to bottom within the tube side, could it happen that the hot side isn’t fully filled with liquid, thereby reducing the heat exchange efficiency? Does the calculation model in the heat exchange software take this situation into account?
For vertical heat exchangers without liquid-liquid phase change, it is a common design practice to have the cold side flow through the shell side with fluid entering from the bottom and exiting from the top, while the hot side flows through the tube side with fluid entering from the top and exiting from the bottom. If properly designed, the hot side will not experience a situation where it cannot be filled with liquid. To ensure that the hot side is filled with liquid and to achieve good heat exchange, the following measures can be taken: 1. Design an appropriate tube bundle structure: By properly designing the tube bundle structure, including parameters such as the number of tubes, their spacing, and diameter, it is possible to ensure that the hot fluid covers each tube thoroughly within the tube side, thereby preventing the situation where the liquid does not fill the space completely. 2. Adjusting fluid velocity: By adjusting the inlet and outlet positions as well as the flow rate of the fluid, the flow conditions can be optimized, allowing the heat transfer medium to cover each tube inside the pipe bank thoroughly and thereby improving the heat exchange efficiency. 3. Use a shunt plate: Employing a shunt plate in the hot-side tube side helps to guide the flow of the heat medium, ensuring its even distribution throughout the tube side and preventing localized accumulation of liquid that could reduce heat exchange efficiency. The calculation structures in heat exchange software typically take these factors into account and perform calculations based on the tube bundle configuration and fluid parameters, to ensure that the designed heat exchanger can achieve efficient heat exchange. When selecting and designing equipment, professional heat transfer software can be used for simulation calculations to obtain the optimal heat exchanger design. .
Many people have this concern, but everyone still uses it in this way.
Whether it’s full or not depends on your flow rate and pressure; it’s not a problem with the heat exchanger software itself
This post was last edited by wanlirn on 2023-7-13 09:22. Is your pipeline open? Then add a distribution plate at the inlet of the upper tube box, similar to that in a falling film heater. If it is a powered closed-loop system, your concerns are unnecessary
Shouldn’t whether it can be filled depend on the flow rate? The flow rate is greater than the upward buoyancy speed of air, allowing all the air to be expelled at once when the device is turned on ；