Seeking help regarding air resistance
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This post was last edited by eastchen on 2009-5-4 17:13. In a shell-and-tube heat exchanger, the water in the shell side exchanges heat with the process fluid in the tube side; under what conditions can an air block be formed on the water side?
What is the principle behind the formation of air resistance? Thank you for your guidance.
This post was last edited by Zhongyuanren on 2009-5-4 09:06. When gas is present in the pipeline, it creates resistance to the gaseous or liquid materials, preventing them from flowing properly; this phenomenon is known as gas resistance.
Air resistance can occur on the water side under the following conditions: 1. Air is not exhausted when the water side is put into use； ⒉The sequence of operation is incorrect; heat flow should be applied first, followed by cooling water.
Air resistance: 1. Air resistance refers to the situation where air generated by high temperatures blocks the oil flow in the oil pipes, preventing the engine from receiving enough oil and causing it to stall. The solution is to improve ventilation conditions or insert insulating gaskets (plates) between the oil pipes and the engine to block the heat radiation emitted by the engine. 2. Air resistance occurs when the oil pipeline experiences high temperatures, causing gasoline to vaporize and form bubbles; in other words, it are bubbles of gasoline rather than air that block the oil flow, and in severe cases this can lead to the car stalling. Pay attention to improving the ventilation of the car engine. The best approach is to stop the vehicle temporarily; once the engine cools down a bit, the problem will be resolved.
Gas resistance, as the name implies, refers to the obstruction caused by a sealed section that hinders the flow of gas through a liquid. The causes can be considered from three aspects: if gas is the cause, it fails to be expelled and remains there ； Secondly, it is caused by incorrect use of circulating water in the pipelines ； It is caused again by vaporization resulting from adding hot materials first and then cold materials. For partitioned heat exchangers, the main concern is incomplete exhaust during operation.
I think if there is air blockage, it might be because the exhaust hasn’t been cleared completely.
In addition to improper operation (inadequate exhaust), another cause of air blockage is an unreasonable pipeline design that results in \"air pockets\".
Could someone upstairs explain what a \"air bag\" is? How does it work?
For partition-type heat exchangers, the water circulation circuit generally has water entering from below and exiting from above, forming an inverted “U” shape. An exhaust valve is usually installed at the highest point of the drainage circuit or at the highest point on the water side of the heat exchanger; proper exhaust should be ensured during startup to avoid the formation of air blocks. If venting is not performed, the air accumulated in the pipeline, due to its lower density, collects at the top of the inverted “U” shape, thereby creating an air-air obstruction.
10# llhhss710818 I would like to ask whether air can accumulate and cause air blockage during normal production as well?