How to calculate the gas flow rate that can pass through a needle valve when it is fully open
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For a certain needle valve, the gas on the upstream side is nitrogen at 6.2 barg and 30°C; after being depressurized to atmospheric pressure, it enters the storage tank to serve as a nitrogen seal. The maximum flow rate is 30 Nm3/h. I would appreciate it if experts could advise on how to calculate the maximum amount of nitrogen that can pass through this needle valve when it fails and is in its fully open state, under a pressure difference of 6.2 bar. Thank you
I don’t understand the calculations, but from another perspective, it’s about traffic that is abnormal. It seems that in terms of management concepts these days, flow meters are the ones that determine what counts; P
First, needle valves are used to control low-flow operations. Second, you mentioned that the check valve fails to stay closed and that the maximum flow rate is considered… so the answer is already there. Brother Three, if it’s fully open, then the pressure difference shouldn’t be 6.2 bar… there should be almost no pressure difference at all.
1. During normal operation, I only need up to 30 Nm3/h of nitrogen flow. 2. When the needle valve fails and is fully open, the pressure upstream is 6.2 barg while the pressure downstream is at atmospheric level; what’s needed is the nitrogen flow rate under these conditions
Your statement about starting up the system is misleading. If you say that only 30 NM3/H of nitrogen is needed to feed into the system, that can’t be determined through calculations – it’s impossible to do so. What needs to be done is to adjust the operating parameters; check whether there are any isolation valves along the entire pipeline, and control the opening degree of those valves. Also, check the flow rate indicated by the flow meter. If everything else is broken, then what’s the point of doing any calculations... I don’t understand
https://bbs.hcbbs.com/thread-2101430-1-1.html I have a question, teacher: When liquid nitrogen is placed in a sealed container (filled to the brim) at normal temperature and pressure and then heated, in the equation Q=cm△T, which specific heat value should be used? On a pressure-enthalpy diagram, does heat transfer occur along isochoric lines?