1. Relationship between pipe diameter and flow rate
Pipe diameter is the first fluid mechanics factor to be considered in the design of Metal pipe fittings. According to the flow formula Q=A×v (Q is the flow rate, A is the cross-sectional area of the pipe, and v is the fluid flow rate), the size of the pipe diameter directly determines the cross-sectional area of the fluid passing through the pipe fitting. When designing, the appropriate pipe diameter needs to be determined based on the expected flow rate. If the pipe diameter is too small, the fluid flow rate will be too high, which may lead to increased energy losses, such as increased resistance losses along the way and increased local resistance losses. For example, in a water supply system, insufficient pipe diameter will cause the water flow rate to be too fast, which will not only produce greater water flow noise, but also increase pipe wear and energy loss. On the contrary, a pipe diameter that is too large will result in material waste and increased costs. It may also lead to low fluid flow rates, causing problems such as deposition.
2. Pipe fitting shape and resistance
The shape of pipe fittings (such as elbows, tees, reducers, etc.) has a significant impact on fluid resistance. When fluid flows through pipe fittings, local resistance will occur due to changes in flow direction or cross-section. Taking an elbow as an example, the fluid will turn around at the elbow. The speed of the outside fluid increases and the speed of the inside fluid decreases, forming a vortex, resulting in energy loss. During design, sudden changes in shape of pipe fittings should be minimized. For example, using an elbow with a large curvature radius can make the fluid turn more gently, reduce the formation of vortices, and reduce local resistance. For tee fittings, reasonable design of the angles and connection methods of branch pipes can make the fluid flow more smoothly when dividing or converging, and avoid fluids from colliding with each other.
3. Inner wall roughness and flow velocity distribution
The roughness of the inner wall of Metal pipe fittings can also affect the flow characteristics of the fluid. A rough inner wall will increase the frictional resistance of the fluid and increase the flow velocity gradient of the fluid near the pipe wall. According to the viscosity principle of fluid, the flow velocity of the fluid is almost zero near the pipe wall, and then gradually increases toward the center of the pipe. This change in flow rate is more dramatic when the inner wall is rough, causing more energy to be used to overcome friction. In the design, for systems with low fluid resistance requirements, pipe fittings with smooth inner walls should be used as much as possible, or special treatments (such as polishing, etc.) should be performed on the inner walls of the pipe fittings to improve flow velocity distribution, reduce resistance losses along the way, and improve fluid transportation efficiency. .
4. Pressure changes and pipe fitting layout
As fluid flows in Metal pipe fittings, pressure changes. When designing the layout of the pipe fitting system, pressure balance and variation patterns need to be considered. For example, in a long-distance fluid delivery system, the fluid pressure will gradually decrease due to resistance losses along the way. Therefore, pressure distribution can be adjusted by properly setting up a booster device or changing the diameter of pipe fittings. At the same time, in complex systems with multiple pipe connections, avoid areas with rapid changes in pressure, as this may lead to cavitation or water hammer. Cavitation can damage pipe fittings and equipment, and water hammer can cause pipes to vibrate or even rupture. Therefore, through reasonable pipe fitting layout and design parameter adjustment, the pressure change of the fluid in the pipe fitting system can be stabilized and the safe and stable operation of the system can be ensured.
