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Introduction to Friction Resistance of Graphite Rods During Use

In the case of 4000 transition flow and turbulence, the friction coefficient is not only related to the number of numbers, but also to the thick of the graphite rods
Roughness. In general, the coefficient of friction decreases, and the change in the number of cases is very large.
1. Some detailed studies have shown that, even in turbulent conditions, the effect of different numbers and roughness on the coefficient of friction is not
The same, this is because the higher the turbulent degree, the thinner the boundary layer, the more rough the graphite rods, the more the protruding part of the tube
The frictional resistance of the main body in the turbulent channel is more serious. The influence of the thickness of the stagnant boundary layer and the roughness of the graphite rods when the turbulence level is not high
It's not obvious.
2. Common steel pipe and more smooth graphite rod (graphite bar is relatively clean and the figure of the heat exchanger) is designed
Most commonly encountered, when RA is greater than 4000, they are in different re number of friction coefficient/can use the right end of the heat exchanger tube
The sub curve is checked.
3. In $number the transitional flow of the Re-4000
Due to the unsteady flow pattern, the friction coefficient f-re curve of the hysteresis and turbulence can be applied. To consider the calculation of the stone
Ink rod fluid resistance should be, usually extending the curve of turbulence to check the friction coefficient of the transition flow.
Calculation of local resistance of graphite rods
Graphite rod local resistance refers to the fluid through the equipment or pipelines import and export, elbow, and other local obstacles to loss of pressure head.
The local resistance calculation has two kinds of equivalent length method and local resistance coefficient method. The equivalent length method is, if the stone that flows through a certain length
The pressure drop of the ink bar is exactly the same as the pressure drop of the pipe with the same cross-sectional area, then the direct resistance can be used instead of the graphite rod.
Local resistance, the length of the straight tube is the equivalent length of the pipe.
The drag coefficient is as follows: The pressure drop of a fluid through a valve and other fittings is relative to the speed at which the fluid flows in the pipe.
The degree of the head is the multiple to indicate that the multiplier is the resistance coefficient.
Graphite Stick Use Conclusion
Use a graphite rod with a smooth, frictional resistance, and control the deformation of the graphite rods during production