Re: Viscosity Of Flyash
Viscosity is normally measured for liquids. By definition It is "the hindrance to the flow of liquid".
What are you intending with this value? ■
Re:
i mean solid viscosity of flyash. ■
Viscosity Of Flyash
Dear Ankita,
Viscosity of solids that do not soften or melt due to heat is a property that is not used in pneumatic conveying, at least to my knowledge. Can you explain why you need this property? Instead of viscosity did you mean elasticity?
I will be glad to help you out if you provide more details of your conveying system.
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Email: polypcc@aol.com
Ph and Fax: 304 346 5125 ■
Re: Viscosity Of Flyash
Dear ankita,
Viscosity is defined as follows:
Shearstress : T / A = TAU= viscosity * dvel /dy (Stokes law)
Tau= viscosity * velocity-gradient
= viscosity :
dimension : N/m^2 * m/m/(sec) = Ns/m^2
dynamic viscosity= viscosity/medium density
dimension : Ns/m^2/(kg/m^3) = Nsm/kg
Viscosity is a material property that is important in flow behaviour along walls and in case of turbulence.
In pneumatic conveying, the viscosity of the product/air mixture should then be used.
As the mixture is in an (over)fluidized state, the viscosity is assumed approximately equal to the air viscosity.
Like mr Agarwal, I never came across this parameter.
Can you explain your intention of knowing this factor?
I am interested,
Teus ■
Teus
Reply
I am using FLUENT CFD software to find the pressure drop in densed phase conveying through pipe.I am using Euler model.So there is an option for giving input for viscosity for solid material.
That is why i need this.
Ankita ■
Re: Viscosity Of Flyash
Originally Posted by Teus Tuinenburg
Viscosity is defined as follows:
Shearstress : T / A = TAU= viscosity * dvel /dy (Stokes law)
Tau= viscosity * velocity-gradient
= viscosity :
dimension : N/m^2 * m/m/(sec) = Ns/m^2
dynamic viscosity= viscosity/medium density
dimension : Ns/m^2/(kg/m^3) = Nsm/kg
Viscosity is a material property that is important in flow behaviour along walls and in case of turbulence.
In pneumatic conveying, the viscosity of the product/air mixture should then be used.
As the mixture is in an (over)fluidized state, the viscosity is assumed approximately equal to the air viscosity.
Like mr Agarwal, I never came across this parameter.
Can you explain your intention of knowing this factor?
I am interested,
Teus
I am using FLUENT CFD software to find the pressure drop in densed phase conveying through pipe.I am using Euler model.So there is an option for giving input for viscosity for solid material.
That is why i need this.
Ankita ■
Re: Viscosity Of Flyash
Dear ankita,
Have a look at: http://ct-cr4.chem.uva.nl/analogies/solid.html
The way you want to calculate a pneumatic conveying system is pure science.
What I understand from a Google search is that a solid flow of particles in suspension are considered as an ideal gas, with temperature (particle velocity fluctuations), pressure (particle collisions impulse) and a fluid like viscosity that can be calculated.
This scientific approach is very enlightening in the physics of two-phase flows (Which is pneumatic conveying).
Whether this is a practical approach for us simple engineers to calculate an installation, I doubt, because of the high number of necessary particle properties (such as your viscosity) and the great number of equations that have to be solved in the time domain.
Computer time will be an issue then and how stable is the calculation against small changes in parameters and starting values?
Nevertheless, I admire your drive and efforts to master this technology.
Very much success
Teus ■
Teus
Viscosity of Flyash
i am using flyash as conveying msterial in dense phase conveying.Can anybody tell me what will be the value of viscosity of this material. ■