What is the relationship between vapor pressure difference and flow rate? And what about the relationship between KV values?
Thread Content
I would like to ask everyone: in a fixed steam pipeline, given the KV value of the control valve, when the pressure difference before and after the valve is 300 kPa, can it be calculated that the current steam flow rate is 3 times the KV value, that is, 1800 kg/h? Can it be understood in this way: by excluding certain influencing factors, such as resistance, for example? There’s another question: with the flow area remaining constant, is the change in pressure difference proportional to the flow rate? The greater the pressure difference, the greater the flow rate and the higher the flow velocity, right?
1. The greater the pressure difference, the larger the flow rate and the higher the flow velocity. Correct. 2. Is the change in pressure difference proportional to the flow rate? Error, nonlinear.
This post was last edited by Watt Energy Saving on 10/9/2019 at 14:31. The calculation methods for the flow characteristics of control valves vary depending on whether they are linear, equal percentage, or quick-opening type. It can only be a positive correlation. When the choked flow condition is reached, the pressure difference increases, and the flow rate no longer increases.
1. When the choked flow condition is reached, the pressure difference increases, and the flow rate no longer increases. 2. If the flow is not at the choked flow state, the flow rate is essentially proportional to the square root of the pressure difference!