Dear Shin Ho Kwon,

Have you read:

Pneumatic conveying, Performance and Calculations:

https://news.bulk-online.com/?p=65

Dense phase- or dilute phase pneumatic conveying:

https://news.bulk-online.com/?p=238

Pneumatic conveying, turbo- or positive displacement air mover:

https://news.bulk-online.com/?p=309

Energy consumption per ton of a pneumatic conveying system:

https://news.bulk-online.com/?p=331

Pneumatic conveying, an unexpected relationship.

https://news.bulk-online.com/?p=445

Pneumatic unloaders: Problems to avoid

https://news.bulk-online.com/?p=74

Influence of electro static charge on pneumatic conveying.

https://news.bulk-online.com/?author=15

Bacterial heating of cereals and meals.

https://news.bulk-online.com/?p=216

Accuracy of pneumatic conveying calculations

https://news.bulk-online.com/pneumat...culations.html

Each calculation method has to account for the material related energy losses.

-acceleration

-velocity losses in bends

-collision losses against the pipe wall and other particles.

As these losses are material related, the specific material related factors must be a part of the calculations. (The famous factor K). These factors can only be derived by calculation from laboratory tests or, better, from field tests.

(A way of reversed engineering)

Many calculation algorithms are based on the calculation of the air only pressure drop plus a material pressure drop, which is then K times the pressure drop for gas. (Darcy equation)

(pressure drop = (1+K) * dpgas)

In the above BulkBlog articles, you can read that the “(1+K)” approach is far from accurate.

Scaling techniques make the calculations even more complex (different Re in test model and real installation).

Moreover, a factor K is valid for the calculation algorithm where it belongs to.

Further, the factor K is a function of the SLR and Re.

I noticed, that you have received the article from Mr Agarwal, which is a good explanatory example.

Success

Teus ■

Dear Shin Ho Kwon,

a new and universal way of presenting and analysing industrial conveying installation supported by a free software program you will find in my recent thread:

https://forum.bulk-online.com/showth...-Installations

Regards, ManfredH ■

Dear Shin Ho Kwon,

The K factor is only valid in the calculation algorithm, with which the K factor is calculated from a laboratory test or a (number of) field test(s).

Therefore the K factor for one calculation method must differ from the K factor, which is used for another calculation method.

I glanced through the article of Chandana Ratnayake.

It is a good description and summary of the available knowledge, research and calculation methods up to day.

Whether it is easy to use an article like this for designing purposes, I doubt.

The K factor represents the amount of energy, which is lost in particle collisions. (and other energy losses)

The chance of an inter-particle collision is increasing with the solid loading ratio and therefore the K factor must increase as well with increasing SLR.

The same theory applies to the gas flow turbulence (Reynolds number).

The higher the turbulence, the higher the chance of collisions.

This is expressed by a K factor, which is also a function of the Reynolds number

The principle of pneumatic conveying is simple.

The calculation of a pneumatic conveying system is complex.

The technology of pneumatic conveying is linked to the installation components and ranges from piping to compressors, filters, e-motors, diesel engines, pneumatics, hydraulics, PLC controls, powder flow mechanics, etc.

Take care

Teus ■

Dear Shin Ho Kwon,

Any calculation method is based on the physical theories that describe the pneumatic conveying phenomena.

In general, all available calculation methods are based on the related physics, however, some approaches are incomplete, some are simple and some are scientific.

The respective manufacturers of pneumatic conveying systems and universities have built their own theory set-up and calculations, based on experience, measurements and mathematics.

For commercial reasons, these methods are kept to themselves or have not proven to be reliable in practice.

Often, the knowledge is based on built installations, whereby the past failures and successes are the basis for the future designs.

When you state

, it should be There are many methods

While everybody is keeping the knowledge hidden from the world, comparing is almost impossible.

And if a designed project meets the specification (or not) is mostly a matter of copying an existing installation or scaling a previously built installation.

Overdesigns are accepted and forgotten.

Under designs are settled and forgotten

Matching designs are claimed on knowledge (even when it was pure luck)

Nevertheless, it is strongly advised to consult the experienced companies in case of hot projects.

For students, working on a study project, it is much more difficult to produce something breaking new, user-friendly, overall applicable, a reliable theory and calculation method or program, other than summarizing the past.

I understand that it is frustrating, but if you want to have a working calculation method, you have to make that yourself.

The paper of Mr Armit T Agawal is probably the most straight forward information, that you can get.

Success

Teus ■

Dear Shin Ho Kwon,

As I said in the previous reply to this thread: There are many methods

I started to build my own pneumatic conveying calculation program about 30 years ago, because I could not get the methods from others and the publications on pneumatic conveying were very inconsistent.

This situation has not changed significantly up till now.

-Many studies, covering detail physics, which are highly scientifically, but not easy to implement on practical installation calculations.

-Simple spread sheet calculations, which result in answers of which it is not possible to judge the reliability.

-Manufacturers, who claim the knowledge and expertise but do not want to reveal their methods.

If you want to compare pneumatic conveying calculation methods, I doubt it is worthwhile to spend so much time and effort in understanding those methods and perform calculations with them and still not knowing which method gives the right outcome.

(If they are comparable anyway, due to the many different approaches)

Re-read:

Pneumatic conveying, Performance and Calculations:

https://news.bulk-online.com/?p=65

You can certainly try it and see what happens.

Have a nice day

Teus ■