Gsant555
Páginas: 5 (1214 palabras)
Publicado: 22 de octubre de 2012
COMSOL 4.2 TUTORIAL
Example 3 (MOMENTUM TRANSFER) Consider two immiscible and viscous liquids, water and transformer oil, flowing at 300 k in the z-direction in a horizontal thin slit of length 0.5 m and width 0.1 m under the influence of a pressure gradient. Both liquids can be considered as incompressible. At the inlet both liquids can be assumed to have the same pressure of 0.02 Pa.Determine the corresponding velocity profile for each fluid.
To simplify the analysis it is convenient to define two subdomains or regions. The first subdomain consists of the liquid water phase and the second one the liquid oil phase. The governing equation for this problem is the Navier-Stokes equation, which is a part of the “laminar flow” physics in COMSOL. The walls should have no slip boundaryconditions and the outlet can be set to zero pressure.The geometry of the system may be defined as follows.
Model Wizard: After opening COMSOL the model wizard will appear to guide you through the initialization of your model. The model wizard asks you what dimensions, physics and study type will be appropriate for your model. For this model Space Dimension: 2D
Physics: Laminar flowStudy Type: Stationary
Complete the Model Wizard by left clicking the finish flag. The interface should now change to “geometry”. Geometry: The geometry of our system can be broken into two regions. Both of which are rectangles of width 0.5 m and height of 0.05 m. One of these regions will contain water, the other oil. Rectangle 1: First, right click the geometry tab and left click “rectangle”from the menu. Next, enter the dimension of the rectangle as below.
Rectangle 2: Do exactly as you did for the first rectangle. Right click “geometry” and then left click on rectangle and set the dimensions as before. Placement: You now have two rectangles of the same dimensions overlapping each other so you can only see one. Left click the rectangle you see and drag it so that one of yourrectangles is right on top of the other. If done properly your display should look like the one below.
Materials: The materials tab is where you can assign the water and oil to their respective domains. We want to assign water to the top domain (rectangle) and transformer oil to the bottom domain. Water: Left click on the “Material” tab. At the top of your interface should be a tab that says“Material Browser”, left click this and then enter “water” into the search bar. Click search.
Right click “water, liquid” and left click “add material to model”, this will make all domains (the upper and lower rectangles) water. This is not what we want, remove the water properties from the lower rectangle (which will be oil) by left clicking it to highlight and then right click to remove selection.Your screen should look like the one below.
Transformer Oil: Again go into the material browser, this time search for “transformer oil”. Add this to the model as before by right clicking and subsequently left clicking “add material to model”.
Add this material to the lower domain (the lower rectangle). Do this by left clicking and then right clicking the lower domain while in the“transformer oil” interface. Your screen will look like the one below.
Laminar Flow: We need to apply the appropriate conditions to our domains so that the correct form of the Navier-Stokes equation can be solved. We will need to set our boundary conditions for inlet, outlet and walls, in addition we need to input the temperature for our model (300k) and select the incompressible form of theNavier-Stokes equation. Incompressible Flow: Left click on the laminar flow tab, this will display the governing equation for our model as well as the physical model being used. Under physical model left click the “compressibility” drop down menu, and select incompressible.
Should become
Temperature: Open up the sub tabs under “Laminar Flow” and left click the “fluid properties” tab.
In the...
Example 3 (MOMENTUM TRANSFER) Consider two immiscible and viscous liquids, water and transformer oil, flowing at 300 k in the z-direction in a horizontal thin slit of length 0.5 m and width 0.1 m under the influence of a pressure gradient. Both liquids can be considered as incompressible. At the inlet both liquids can be assumed to have the same pressure of 0.02 Pa.Determine the corresponding velocity profile for each fluid.
To simplify the analysis it is convenient to define two subdomains or regions. The first subdomain consists of the liquid water phase and the second one the liquid oil phase. The governing equation for this problem is the Navier-Stokes equation, which is a part of the “laminar flow” physics in COMSOL. The walls should have no slip boundaryconditions and the outlet can be set to zero pressure.The geometry of the system may be defined as follows.
Model Wizard: After opening COMSOL the model wizard will appear to guide you through the initialization of your model. The model wizard asks you what dimensions, physics and study type will be appropriate for your model. For this model Space Dimension: 2D
Physics: Laminar flowStudy Type: Stationary
Complete the Model Wizard by left clicking the finish flag. The interface should now change to “geometry”. Geometry: The geometry of our system can be broken into two regions. Both of which are rectangles of width 0.5 m and height of 0.05 m. One of these regions will contain water, the other oil. Rectangle 1: First, right click the geometry tab and left click “rectangle”from the menu. Next, enter the dimension of the rectangle as below.
Rectangle 2: Do exactly as you did for the first rectangle. Right click “geometry” and then left click on rectangle and set the dimensions as before. Placement: You now have two rectangles of the same dimensions overlapping each other so you can only see one. Left click the rectangle you see and drag it so that one of yourrectangles is right on top of the other. If done properly your display should look like the one below.
Materials: The materials tab is where you can assign the water and oil to their respective domains. We want to assign water to the top domain (rectangle) and transformer oil to the bottom domain. Water: Left click on the “Material” tab. At the top of your interface should be a tab that says“Material Browser”, left click this and then enter “water” into the search bar. Click search.
Right click “water, liquid” and left click “add material to model”, this will make all domains (the upper and lower rectangles) water. This is not what we want, remove the water properties from the lower rectangle (which will be oil) by left clicking it to highlight and then right click to remove selection.Your screen should look like the one below.
Transformer Oil: Again go into the material browser, this time search for “transformer oil”. Add this to the model as before by right clicking and subsequently left clicking “add material to model”.
Add this material to the lower domain (the lower rectangle). Do this by left clicking and then right clicking the lower domain while in the“transformer oil” interface. Your screen will look like the one below.
Laminar Flow: We need to apply the appropriate conditions to our domains so that the correct form of the Navier-Stokes equation can be solved. We will need to set our boundary conditions for inlet, outlet and walls, in addition we need to input the temperature for our model (300k) and select the incompressible form of theNavier-Stokes equation. Incompressible Flow: Left click on the laminar flow tab, this will display the governing equation for our model as well as the physical model being used. Under physical model left click the “compressibility” drop down menu, and select incompressible.
Should become
Temperature: Open up the sub tabs under “Laminar Flow” and left click the “fluid properties” tab.
In the...
Leer documento completo
Regístrate para leer el documento completo.