Question 1

What Is Static Pressure?

Accepted Answer

The pressure generated by the irregular movement of air molecules on the pipe wall is called static pressure.

When calculating, the static pressure with absolute vacuum as the calculation zero is called absolute static pressure. The static pressure at which the atmospheric pressure is zero is called relative static pressure.

The air static pressure in the air conditioner refers to the relative static pressure. The static pressure is positive when it is above atmospheric pressure and negative when it is below atmospheric pressure.

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Question 2

What Is dynamic pressure?

Accepted Answer

Dynamic pressure, when an object is moving in a fluid, the surface is facing the direction of fluid motion. The fluid is completely blocked, and the fluid velocity here is 0. Its kinetic energy is converted into pressure energy, and the pressure increases. Its pressure is called the total resistance pressure (referred to as total pressure or total pressure, represented by P). The difference between it and the undisturbed pressure (i.e. static pressure, represented by P static) is called dynamic pressure (represented by P dynamic)

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Question 3

What is the difference between static and dynamic pressure?

Accepted Answer

The biggest difference between dynamic pressure and static pressure is the different definitions. Static pressure refers to the pressure on the surface of an object when it is at rest or in uniform linear motion. And dynamic pressure is the difference between total pressure and static pressure. They are all within the domain of fluid dynamics.

Both static pressure and dynamic pressure are knowledge in the field of physics. The biggest difference between them is the different definitions. Static pressure refers to the pressure on the surface of an object at rest or in uniform linear motion.

When an object moves in a fluid, the fluid facing the surface of the object is completely blocked. The velocity of the fluid is 0. Then the kinetic energy of the fluid is converted into pressure energy, which increases the pressure on the object. This pressure is called total pressure.

The dynamic pressure is the difference between the above-mentioned total pressure and static pressure.

Both dynamic pressure and static pressure are in the field of fluid dynamics. It is a branch of fluid mechanics. It studies the motion law of fluid under the action of force and its interaction with the boundary.

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Question 4

what is residual water pressure?

Accepted Answer

"Residual pressure" refers to the residual pressure in the pipeline, gas storage tank, and equipment after the system is shut down, such as boiler steam, air compressor station, etc.

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Question 5

what is dynamic water pressure?

Accepted Answer

Dynamic water pressure (dynamic water pressure) is the normal force acting on the interface between two parts of the moving liquid or on the contact surface between the liquid and the solid. Also known as the osmotic force.

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In the process of water flowing in the soil, it will be affected by the soil resistance, causing the water head to gradually lose. At the same time, the infiltration of water will produce a drag force on the soil skeleton, resulting in changes in the stress and deformation in the soil body. The drag force generated by the soil skeleton is called the seepage force.

In many hydraulic structures, earth dams and foundation pit projects, the size of the seepage force is one of the important factors affecting the safety of the project. cause the construction of the project to be interrupted, and even endanger the safety of adjacent buildings and facilities

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Question 6

what is static pressure in hvac?

Accepted Answer

The static pressure box is a necessary accessory for the air supply system to reduce the dynamic pressure, increase the static pressure, stabilize the airflow and reduce the airflow vibration. Its function is to change the dynamic pressure into static pressure, evenly distribute the air volume, and mostly used in front of the slit tuyere.

The pressure generated by the irregular motion of air molecules hitting the pipe wall is called "static pressure". Static pressure is the pressure perpendicular to the direction of fluid movement, and its function is to overcome the resistance in the process of fluid transportation. Then the purpose of establishing a static pressure box is to obtain static pressure.

Total pressure = dynamic pressure + static pressure: the total pressure of the fan is unchanged, and the wind speed decreases, which means that the dynamic pressure becomes smaller, and the static pressure increases.

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When supplying air with multiple air ducts, in order to make the air pressure of each air duct the same, it is necessary to establish a static pressure box, so that the dynamic pressure is all converted into static pressure, and then evenly distributed to each air duct.

In the same way, when the multi-air duct returns air, a static pressure box is also required. The air in front of the surface cooler can be fully mixed. Some single air duct air supply pipes are also equipped with static pressure boxes. The purpose is to use the static pressure box to reduce noise. The principle is that the speed of air entering the static pressure box is significantly slower, and the wind noise will be reduced.

The design principle of the static pressure box: the function of the static pressure box is to provide uniform pressure for each branch pipeline. Theoretically, the static pressure inside the static pressure box is equal everywhere. That is to say, the flow rate inside the static pressure box is zero everywhere. The condition for this is that the volume of the plenum is infinite.

This is impossible in engineering projects. Generally, the wind speed in the box can be controlled below 2m/s, or it can be greatly reduced relative to the wind speed of the inlet and outlet ducts.

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Question 7

What is hydrostatic pressure of liquid?

Accepted Answer

Hydrostatic pressure is: the normal force acting on the interface between two parts of a stationary liquid or on the contact surface of a liquid and a solid is the pressure exerted by a homogeneous fluid on an object. This is an omnidirectional force and is applied uniformly to all parts of the surface of the object. An increase in hydrostatic pressure reduces the volume of the object under force, but does not change its shape.

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Height of Water Column		Pressure
(m)	(ft)	(kPa)	(bar)	(atm)	(psi)
1	3.28	9.81	0.098	0.097	1.42
2	6.56	19.6	0.196	0.194	2.85
3	9.84	29.4	0.294	0.290	4.27
4	13.1	39.2	0.392	0.387	5.69
5	16.4	49.1	0.491	0.484	7.11
6	19.7	58.9	0.589	0.581	8.54
7	23.0	68.7	0.687	0.678	10.0
8	26.2	78.5	0.785	0.775	11.4
9	29.5	88.3	0.883	0.871	12.8
10	32.8	98.1	0.981	0.968	14.2
12	39.4	118	1.18	1.16	17.1
14	45.9	137	1.37	1.36	19.9
16	52.5	157	1.57	1.55	22.8
18	59.0	177	1.77	1.74	25.6
20	65.6	196	1.96	1.94	28.5
25	82.0	245	2.45	2.42	35.6
30	98.4	294	2.94	2.90	42.7
35	115	343	3.43	3.39	49.8
40	131	392	3.92	3.87	56.9
50	164	491	4.91	4.84	71.1
60	197	589	5.89	5.81	85.4
70	230	687	6.87	6.78	100
80	262	785	7.85	7.75	114
90	295	883	8.83	8.71	128
100	328	981	9.81	9.68	142

What is Static Water Pressure?