Working principle of differential flowmeter_calculation formula of differential pressure flow
Traditional differential pressure flow meters (such as orifice plates, etc.) are all throttling differential pressure flow meters. Its working principle is based on two laws of fluid mass conservation (continuity equation) and energy conservation (Bernoulli equation) in a closed pipeline. Here everyone must first review the essence of the two laws of mass conservation (continuity equation) and energy conservation (Bernoulli equation). Only by mastering these two laws can we understand the working principle of differential pressure flowmeter, and The principles of all throttling differential pressure flowmeters are also understood. Let's review the two laws to illustrate the working principle of the tower flowmeter (or differential pressure flowmeter). The law of mass conservation (continuity) equation) and the law of conservation of energy (Bernoulli equation), which can be understood in this way: Conservation of mass: when a fluid flows in a closed pipe, when it encounters a throttling piece, its mass before and after the throttling piece is constant , expressed as the continuity equation: V1*A1*ρ1=V2*A2*ρ2 (liquid: V1*A1=V2*A2) Energy conservation: expressed by the Bernoulli equation as referring to the pressure of the fluid in the closed pipeline It has the following relationship with the flow rate:
the
P+1/2V2ρ=Constant
For pipes with throttling parts: P1+1/2*(V1)2*ρ1=P2+1/2*(V2)2*ρ2
In the formula: A1 and A2 are the cross-sectional areas before and after the throttling part respectively;
V1 and V2 are the flow velocities at A1 and A2 respectively;
P1 and P2 are the pressures at A1 and A2 respectively
ρ1 and ρ2 are the fluid densities at A1 and A2 respectively;
Differential pressure flow calculation formula
Differential pressure flowmeters are the most widely used flowmeters, and five-element analyzers rank first among all kinds of flowmeters. In recent years, due to the advent of various new flowmeters, its usage percentage has gradually declined, but it is still the most important type of flowmeter.
The formula for fluid volume flow rate of differential pressure flowmeter is:
v=aA √2/j(p-q)
v--volume
j--liquid density
a--flow coefficient, related to flow channel size, pressure taking method and flow rate announcement
A--hole plate opening area
p-q--pressure difference
