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 July 7, 2009, 04:59 help about volume fraction #1 New Member   Qiaojie Li Join Date: Jul 2009 Posts: 3 Rep Power: 9 hi all in CFX, volume fraction is defined as the fraction of the control volume occupied by that phase.(right?) is this ,for example,i have 57%(volume fraction)metal power and 43% binder mix together, and should i set the volume fraction of metal powder is 0.57 and the binder is 0.43? thanks!

 July 7, 2009, 05:41 #2 Senior Member     George Join Date: Mar 2009 Location: Birmingham, UK Posts: 257 Rep Power: 10 yes however it depends on how you want to initialise your problem. if the two phases are uniformly distributed in your domain then use the values you mentioned to set one of the phase and leave the other on automatic. if your problem has byoancy effects or your initialisation needs a bit more control you will need to define it using ccl. if you have gas/liquid mixtures make sure you calcualte the state and expansion of the gas (density,ideal gas law) depending on the inlet conditions (temp,presure) __________________ Top 4 tips 1. Knowledge is everything and Ignorance is dangerous. 2. Understand your limitations and try to eliminate them. 3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window. 4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials

 July 10, 2009, 04:46 #3 New Member   Qiaojie Li Join Date: Jul 2009 Posts: 3 Rep Power: 9 hi George I want to simulate a metal injection molding process using CFX.In this situation , we mix the metal powder(solid particle) with the binder(continuous liquid) together,the metal powder have a high volume farction(50%-75%).which model should i use? solid particle collision models? How can i monitor the filling process, i mean how to determine is full filled or not? thanks!

 July 10, 2009, 06:14 #4 Senior Member     George Join Date: Mar 2009 Location: Birmingham, UK Posts: 257 Rep Power: 10 1) what you want to get from your simulation; "simulate a metal injection molding process" is not a well defined description 2) what you mean "How can i monitor the filling process, i mean how to determine is full filled or not". you have logical criteria that you determine if the process is "full or not" can you write these criteria using maths? 3) you need to look into the differences between eulerian-eulerian and lagrangian-eulerian multiphase models. usually for mixing vessels if you're not interested for particle collision or you have a lot of particles engineers go for eulerian-eulerian multiphase models however it does depend what you want to do. __________________ Top 4 tips 1. Knowledge is everything and Ignorance is dangerous. 2. Understand your limitations and try to eliminate them. 3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window. 4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials

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