Let’s analyze whether the pipeline is full or not in this situation
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This pipeline overflows from the upper part of the liquid seal tank into the cooling tower; there are 2 overflow openings, one higher and one lower. The first overflow opening is located 6.8 meters away from the outlet of the cooling tower, while the second opening is 0.6 meters higher than the first. Both openings have a diameter of DN600. These two pipelines converge into one DN1000 pipeline, which then sends the fluid to the cooling tower through two DN300 pipelines. In other words, the pipeline above is larger in diameter, while the one below has a smaller diameter. The total resistance of this piping system is approximately 0.5 meters of head. Under such conditions, is the larger pipeline above fully filled with fluid, or is it operating at a high flow rate with partial filling?
Based on the information provided, we can draw the following conclusions: 1. Since the overflow port is connected to the upper part of the liquid seal tank, the liquid overflows from the tank into the pipeline; therefore, the pipeline is filled with fluid, that is, it is at full capacity. 2. The large pipe mentioned above is relatively large and has low total resistance, which suggests that the flow velocity in this pipe is high. In summary, based on the analysis of the given conditions, the large pipe mentioned above should be at full capacity with a relatively high flow velocity. .
With a constant flow rate, u1a1 = u2a2; since the cross-sectional area of the larger pipe, a1, is greater than that of the smaller pipe, a2, its flow velocity u1 is much lower than that of the smaller pipe, u2. The flow rate is low. It’s difficult to determine whether the pipe is full; going to the site and listening or checking for any airflow sound should help determine whether the pipe is full.
Checking the traffic volume; if it’s high enough, the pipeline might be full. If the flow rate is only low, the pipeline cannot maintain a high liquid level
It depends on the amount of overflow. But there is a common principle: the design of overflow pipes does not allow the pipes to be filled to capacity; if they are filled, then what purpose does the overflow channel serve?
When the pipe is not full, the flow rate is not very high either
If the higher overflow pipes have started to flow, it’s likely that the lower ones are also full. There’s not even time to drain all the water; a second pipe is needed. If it’s only possible to determine whether the pipe is full by observing the flow in the first pipe, and the level of overflow water is very low, then it should be impossible for the pipe to become full
This post was last edited by wwyyxxz on 2023-7-18 at 23:01. Practical experience on site tells us that as long as the overflow port is not full, air will be carried down; when it’s full, that’s not possible. But if all the overflow ports are submerged, the pipe will definitely be full; it depends on the actual situation.