The relationship between flow velocity and pressure, and the relationship between fluid pressure and

First of all, what type of flow meter do you have?

Secondly, did you measure several flow meters in series? If they are connected in series, what is the installation distance between them? If it is an orifice flowmeter, there should be a requirement for the installation distance.

Finally, you don't have to worry about the differential pressure, as long as the flow rate is accurate. Even if the differential pressure is the same after multiple units are connected in series, the flow rate may not be the same, because the s-value of your pipe has changed.

When the eight tables are connected in series, do they read the same amount between them? If they can be self-consistent, then there is no problem, don't dwell on the pressure difference

Hope together**

1. The pressure is not proportional to the flow rate, with the pressure difference, pipe diameter, section shape, whether there is a bend, the roughness of the pipe wall, and whether the viscosity properties of the equal diameter fluid ......, the relationship between pressure and flow rate cannot be determined. 2. If you want to ensure the flow rate, it is recommended that you install a flow meter and a regulating valve. Constant volume conveying can also be considered.

For the fluid to flow, there must be a pressure difference (note: not pressure!). , but it is not necessary that the greater the pressure difference, the greater the flow rate.

When you close the control valve smaller, you will find that the pressure difference between the front and back of the valve is larger, but the flow rate is smaller. Hydraulic calculations for pipelines include hydraulic calculations for long pipes and hydraulic calculations for short pipes. The difference is that the latter ignores the local head loss in the calculation and only considers the head loss along the way.

The head loss can be understood as the frictional force of the relative motion of the solid) Taking the commonly used free outflow of long pipes as an example, the calculation formula is h=(v 2*l) (c 2*r), where h is the water head, which can be converted by pressure, l is the length of the pipe, v is the flow velocity of the pipe outflow, r is the hydraulic radius r = pipe section area inner wall perimeter = r 2, c is the Xie Cai coefficient c=r (1 6) n, n is the roughness, its size depends on the smoothness of the pipe wall, and the smooth pipe is taken between the dirty pipe and to.

Blowing between two sheets of paper in close proximity proved that the flow rate was proportional to the pressure.

The relationship between the pressure of a fluid and the flow velocity.

The greater the velocity of the fluid, the lower the pressure; The lower the flow velocity of the fluid, the greater the pressure. This effect was invented by Bernoulli, hence the name "Bernoulli effect". The Bernoulli effect is applicable to all fluids, including gases, and is one of the basic phenomena when a fluid flows steadily, reflecting the relationship between the pressure and velocity of the fluid.

Fluid. Liquids and gases are capable of flowing in addition to having a certain mass. They are collectively referred to as fluids.

Fluid pressure as a function of flow velocity.

Low pressure at high gas and liquid velocities; The pressure is strong at the position where the flow rate is small. This is the reason why the ships could not travel too closely.

The lift of the aircraft.

Due to the asymmetry of the shape of the wing cross-section, the oncoming wind is divided into upper and lower parts by the wing, and in the same time, the air flow above the wing passes a longer distance, the speed is larger, and the pressure on the wing is smaller; The lower air flow travels a shorter distance, the speed is smaller, and the pressure on the wing is greater, resulting in an upward lift.

The Bernoulli effect.

In 1726, Bernoulli carried out numerous experiments and finally discovered the "boundary layer surface effect": as the fluid velocity increases, the pressure at the interface between the object and the fluid decreases, and vice versa, the pressure increases. In honor of the scientist's contributions, the discovery is known as the "Bernoulli effect".

Bernoulli effect is applicable to all ideal fluids, including liquids and gases, and is one of the basic phenomena when the fluid flows steadily, reflecting the relationship between the pressure of the fluid and the flow velocity, and the relationship between the flow velocity and the pressure: the greater the flow velocity of the fluid, the smaller the pressure; The lower the flow velocity of the fluid, the greater the pressure.

Pressure and flow rate are calculated by the formula:

Flow velocity = flow rate of pipe cross-sectional area. Assuming that the flow rate is s cubic meters and the radius of the circular pipe is r meters, then the flow velocity v:v=s (.

Flow rate = flow rate (pipe ID pipe ID 4).

Pipe Inner Diameter = sqrt (flow rate), sqrt: open squared.

The volume or weight of a fluid passing through a certain cross-section in a certain period of time is called flow. The unit of flow expressed by volume is l s or ( m 3 h); The unit of flow expressed by weight is kg s or t h.

When the fluid flows in the pipeline, the distance it flows through in a certain period of time is the flow velocity, and the flow velocity generally refers to the average flow velocity of the fluid, and the unit is m s.

The relationship between pressure and flow velocity is such that when the flow velocity of an object is zero, then the pressure is strong. If it is air, then if the speed of air flow is zero. In the static state, it is said that the pressure is generated, that is, the atmospheric pressure.

But when the air is moving, the pressure changes. According to Bernoulli's principle, the relationship between fluid pressure and flow velocity is like this. The higher the velocity of the gas, the lower the pressure.

You can look up such related companies on the Internet, and this formula is usually introduced in college.

Therefore, in junior high school physics, it is only necessary to remember that where the flow velocity in the fluid is large, the pressure is small.

For example, the air velocity above the wings of an airplane is high, and the air velocity below is small. Either where the flow velocity is high, the pressure is small, and an upward lift force will be generated. That's why the plane goes up.

The relationship between fluid velocity and pressure.

There is a direct relationship between the pipe diameter and pressure and the flow rate. When doing chemical process design (piping) in the design institute, the flow rate is first defined according to the relevant data, and there is a recommended value for the flow rate of the medium in the second volume of the "Chemical Process Design Manual Fourth Edition" (in general, it is based on experience) - this is how the fluid flow rate is obtained.

q=πr^2√（2p/ρ）

where q is the flow rate, r is the pipe radius, and p is the pressure and density of the liquid.

There is a close correlation between pressure and flow rate. That is, the pressure increases, the flow rate increases; The pressure decreases and the flow rate decreases. This relationship can be explained by the physical phenomenon of pressure driving fluid flow, i.e., the force that drives fluid flow can be measured by pressure, i.e., there is a proportional relationship between the pressure difference of the fluid and the flow velocity.

In a given fluid pipeline, when the pressure of the fluid increases, the flow rate also increases, at this time the energy conversion efficiency of the fluid increases, and the flow rate also increases, and vice versa. When the fluid flows in the pipe, the flow rate will change even if the pressure is constant, and this change is mainly determined by the structural parameters of the fluid pipe and the physical properties of the fluid itself. Therefore, from a physical point of view, the relationship between pressure and flow velocity is very close, and a change in pressure will lead to a change in flow velocity, and vice versa.

Through this relationship, we can effectively measure and control the pressure and flow rate of the fluid for design and operation purposes.