Explanation regarding the principle that \"during the commissioning of heat exchangers, the water temperature rise rate should be kept as low as possible (≯1.5°C/min)\"?
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Hello, everyone. I recently took an exam, and one of the questions was: “When putting a heat exchanger into operation, it is necessary to follow the principle that the rate of increase in water temperature should be as low as possible (≤1.5°C/min).” Regarding this question, I would like to understand why the rate of increase in water temperature cannot exceed 1.5 degrees per minute Is it because when putting it into use, it is necessary to ensure that the rate of temperature exchange between the cold source and the hot source’s water cannot be too fast? Is the rate of increase in water temperature caused by a cold source or a hot source? Since this is my first time dealing with this, my questions might be rather naive; please forgive me, experts. I hope to get answers from everyone. Thank you!
This is the first time I’ve seen this kind of problem. Personal understanding: Preventing water from vaporizing instantly during heating helps avoid issues such as reduced heat transfer efficiency, as well as damage to the equipment caused by vaporization (cavitation corrosion).
Thank you for your explanation, sir. I still don’t quite understand it. A temperature rise rate of no more than 1.5°C/minute seems very low; if it were a bit higher, say 5°C/minute, it probably wouldn’t vaporize instantly, right? However, the heat transfer efficiency should be better the lower the temperature rise rate; am I understanding this correctly? Still, thank you for the ideas you provided; they have helped me learn new things. Thanks:handshake
Coolers generally require that the temperature of the medium to be cooled not exceed 150°C, while the return temperature of the cooling water should not exceed 40°C. The so-called “instant vaporization” referred to here is a rather extreme condition (which does indeed exist in reality), and it also involves the process of scaling. Sometimes, even if vaporization does not occur, scaling still forms on the water, which likewise affects heat transfer efficiency.
Sorry for the late reply. Thank you for your answer. One more question: why is the upper limit for the temperature rise rate set at 1.5°C/min? Is there anything special about this? Can too rapid a temperature rise cause thermal stress, thereby damaging the equipment as well?
The last edit to this post was made by xlxuiin on 2015-11-23 at 11:18. What was mentioned earlier are the requirements related to the manufacturing process, with the aim of achieving efficient heat exchange and saving thermal energy； Of course, there are also requirements regarding the safe operation of the equipment itself, which is one of the factors that must be taken into consideration.
When considering temperature rise, it is primarily the impact on the equipment itself that is taken into account; too rapid a temperature rise can affect the internal structure of the equipment’s material (such as creep)