Re: Product Friction Factor
Dear Mr. Tanase,
I started (many years ago) to research the true meaning of the parameter Solid Loss Factor.
My idea was that the solid loss factor must be related to the turbulence of a gas/material, as the turbulence is related to the number of collisions.
I made a list of a number of ship unloaders for cement and created a table showing the traditional K-factor against the pipe Reynolds number.
The result was a number of curves with the general regression formula:
K(n) = a(n) * Re^1
The found array of the parameter a(n) was then plotted against the Solid Loading Ratio.
The regression line of a(n) was a = SLF^10^-12 * SLR^3
Combined, the formula for the K-factor became:
K= SLF^10^-12 * SLR^3* Re^1
Then I realized that the chance of a collision between particles is related to the mixture density. (more particles more collisions)
From there I recalculated the SLF factor for each pneumatic conveying installation and material of which I was able to gather the layout and properties with, an at that time, newly developed algorithm the SLF factors based on the field performance.
Using the obtained SLF factors and calculation algorithm, I calculated and built new installations up to 800 tph. The measured performance at commission of those installations were always within the guarantee clauses and lead to new insights.
The SLF is part of a formula for pressure drop, due to material energy losses.
I could have the factor 10^-12 hidden in that formula and the SLF would have been not “very, very” small. You would not have noticed.
The SLF factor is comparable to your factor alfa, although alfa is related to another calculation algorithm. ■
Teus
Product friction factor
Dear Mr. Teus,
In the calculation of a pneumatic conveying system, there is a product/air flow speed/pipe dependent variable denominated as K from basic Gasterstadt eq.
I use it as Alfa.
For the same product and the same pipe inside surface, this variable is decreasing with velocity increasing and is increasing with pipe diameter increasing. For wheat flour and intermediate stocks in flour milling, it goes from 0,22 (for pipe diam.=50 mm and air flow speed of 15 m/s) to 0,32 (for pipe diam.=150 mm and air flow speed of 25 m/s).
I can understand it and our calculations i use this experimental determinations table.
And now arrive at the question:
-in your calculations chart, there is one more variable namely "product loss factor" and i observed it has very small value. For example in the project you checked for us, it was only 1,374712E-10, that means 1,374712x10^(-10). Very very small.
-what is the physical meaning of this variable and where it is involved in basic ?
Thank you very much for your valuable comments.
Sincerely yours,
Tanase TANASE ■