[ravanthu]

While modelling erosion by solid particle of a wall, how to get the total mass fraction impacting a particular wall surface. Appreciate an early reply.

How to modify the fortran file used for calcualting the erosion. I am having the modified Finnie model equation based on the erosion test conditions..

Thanks in advance...

[ghorrocks]

Have you done the particle erosion tutorial example?

What do you mean by "total mass fraction impacting a particular wall surface"? This question does not make sense. Do you mean the number of impacts? Or the energy of the impacts? Or which particles are impacting?

[ravanthu]

Originally Posted by ghorrocks

Have you done the particle erosion tutorial example?

What do you mean by "total mass fraction impacting a particular wall surface"? This question does not make sense. Do you mean the number of impacts? Or the energy of the impacts? Or which particles are impacting?

Thanks for an early reply.. Yes. I am interested in the number of impacting particle. The CFX solver calculates the erosion rate intensity based on the particle number rate, the velocity and function of impact angle. Obviously one need to determine these two variables based on experiments at different velocity and impact angle for different wall material. The output of CFX on erosion rate intensity will be accurate when velocity exponent and function of theta is known. The velocity exponent has been calculated by conducting xperiments at three diff. velocities and fitting a power law fit. In order to take care of impact angle effect i.e. f(theta), the graph of SIN(impact angle)Vs the normalized erosion loss data wrt to the 90 deg impact angle has been made. This give rise to theta effect in terms of a multiplier as 1 at 90deg impact angle. Now I need to incorporate these two variables ( exponent "N" and f(theta) in the already available Finnie erosion model in CFX. As this requires writing the fortran code and compiling ( which will be taken up subsequently).
Meanwhile, I would like to do the calculation of erosion rate based on no. of particle impacting the wall along with velocity effect and f(theta) manually with the assumption that the velocity of the particle is same as that of the continuous fluid medium ( low particle size and dilute phase (<5%)and the impact angle is same as that the wall position ( stream lined flow).

If I get the total mass hitting a wall , i shall be able to compute the erosion rate of that wall based on the established relation between erosion loss with angle at particular velocity.. Hence I require the mass of particle impacting the wall information..

Can we get from CFX, the particle impact angle data for all the considered no. of particles?..

Awaiting your support..

[ghorrocks]

Have you read the documentation? It describes an example of how to implement the Finnie model in fortran, so it gives you access to all the variables Finnie uses in the model (which includes angle).

Have a look in the CFX Modeling guide and Theory Guide.

[ravanthu]

Originally Posted by ghorrocks

Have you read the documentation? It describes an example of how to implement the Finnie model in fortran, so it gives you access to all the variables Finnie uses in the model (which includes angle).

Have a look in the CFX Modeling guide and Theory Guide.

Thanks once again...... I had gone thro the theory guide and documentation many times. However, the doubt still stand unclear..
How to get the particle impact angle data at a particular wall viz. the volume fraction of particle impacting a wall. Moreover, the output results in terms of kg of metal loss/m^2 area of wall per second ( kg/m^2s) invariably requires the total quantity hitting at the wall. How can I get explicitly that information of mass of particle ( %ge) which was my first query..

[ghorrocks]

Have another look at the pt_erosion.F file. It has the variable ANGLE (and ANGLE_DEG) which is the collision angle.

[ravanthu]

Originally Posted by ghorrocks

Have another look at the pt_erosion.F file. It has the variable ANGLE (and ANGLE_DEG) which is the collision angle.

The fortran code is going to be written for Pt_erosion. Meanwhile, the immediate requirements is how to estimate the life ( thinning rate due to erosion) of the wall. Can I use the averaged volume fraction of particle data at a given wall and experimentally derived erosion data ( kg of metal loss/kg of abrasive) ( kindly refer attached jpg of snapshot of result window) for calculating the wall life...

How to get the ANGLE data though it is already available as variable. However, while choosing the variable for wall, it is not available..

[Whitebear]

How to erase wrong answer in here? It's very difficult to remove my wrong writing.