Problems with internally threaded pipes for experiments
Thread Content
As mentioned, I would like to ask for advice on the issue of internally threaded pipes. 1. How are internally threaded pipes processed? 2. In my experiment, I want to make a small internally threaded pipe with an inner diameter of 20mm and a length of 100mm. There is a stainless steel filter on each side of the pipe. Please tell me if there is liquid in my tube and the tube is placed horizontally. Can the liquid entering the internally threaded pipe from the inlet produce a spiral liquid form in the pipe?
This post was last edited by casondu on 2019-3-2 11:47 Internally threaded pipes are mainly used to enhance heat transfer and avoid or delay the deterioration of heat transfer. This is achieved through the swirling flow of the fluid in the tube.
personal opinion: It seems that increasing the fluid disturbance in the above-mentioned reactor through internal threads has little effect. On the one hand, the reactor is filled with solid reaction materials, and the pipe wall will not have a great impact on the flow direction and flow rate in the filler. ； On the other hand, the flow rate of the reaction fluid is small, the flow pattern in the pipeline is usually laminar flow, and the mixing effect is poor. It is recommended to try directly by adjusting the particle size distribution of the solid phase reactants and changing the aperture of the internal circulation channels of the material. If you want to change the macroscopic flow direction of the fluid, you can also place several forward and reverse spiral spoilers in the reaction tube. The effect should be better than internal threads. For the spoiler setting and processing, you can refer to the pipe mixer structure and download it from Baidu.
Well, thank you for your reply. The amount of particles in my reactor is very small, tens of mg. But as you said, because the flow rate is low, the characteristics of macroscopic laminar flow will hardly change, right? Then let me look at the spoiler you mentioned on Baidu. Is it troublesome to process this kind of thing in a small pipe diameter?
It seems that the number of solid particles in your reactor is very small, and there is no need to make the reactor so large for what reason.
Spoiler processing is very simple, and you can even do it yourself: Choose a stainless steel sheet with a width of 5~10mm, cut it into short strips of about 50mm length, twist it into a twist shape, and combine the two strands into a spoiler. You can refer to the picture below:
Also provide a suggestion: The reactor can be placed from a horizontal position to a vertical position, with the bottom in and the top out, and the liquid supply flow rate used to form a suspension and agitation of the solid particles. This is simple and easy, and the effect should be obvious.
In fact, the reactor size mentioned in the literature is the inner diameter: 4.6mm, the length is 40mm, but the solid sample volume is 50mg, but it has little to do with the content of my research. My experiment is to soak the sample with a continuously flowing liquid and then detect the leachate. And I want to increase the sample size appropriately, for example to a few hundred mg or to a few grams. So I want to increase the size of the reactor appropriately, and I want to increase the turbulence of the liquid. One is to prevent solids from accumulating on the downstream filter, and the other is to increase experimental efficiency. For both purposes I wanted to make the reactor size larger. If it is arranged in a vertical manner as you said, then the liquid flows from bottom to top. Since the solid particles are very small, will they be bound to the upper filter surface by the impact of the water flow instead of being in a suspended state?
It would be better to use vertical flow to form a fluidized bed for only leaching rather than reaction. If you are worried that solids will accumulate on the downstream filter screen due to excessive flow rate, you can optimize the flow rate. This can be achieved by reducing the liquid supply displacement and increasing the reactor cross-sectional area. What is the particle size and density of the solid particles? Calculate the particle settling velocity, and then match the flow rate to suspend the solid phase.
If my reaction material is small-density particles such as wood that are less dense than water, then the particles will float when the fluid is stationary. In this way, when a vertical reactor is used, will the particles accumulate on the downstream filter screen due to the bottom-up effect of water flow? Even if the flow rate is small, the particles will still float on the top of the liquid and cannot form a suspended state.
If the density of the solid particles is small and they float on the liquid surface, then the same problem exists in the advection tube, and the liquid level in the upper part of the advection reactor is larger, so the elution effect may be worse.