EDEM Tutorial: Heat Transfer

Transcription

1 EDEM Tutorial: Heat Transfer

2 Copyrights and Trademarks Copyright 2015 DEM Solutions. All rights reserved. Information in this document is subject to change without notice. The software described in this document is furnished under a license agreement or nondisclosure agreement. The software may be used or copied only in accordance with the terms of those agreements. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or any means electronic or mechanical, including photocopying and recording for any purpose other than the purchaser s personal use without written permission. DEM Solutions 49 Queen Street Edinburgh EH2 3NH UK EDEM incorporates CADfix translation technology. CADfix is owned, supplied by and Copyright TranscenData Europe Limited, All Rights Reserved. This software is based in part on the work of the Independent JPEG Group. EDEM uses the Mersenne Twister random number generator, Copyright , Makoto Matsumoto and Takuji Nishimura, All rights reserved. EDEM includes CGNS (CFD General Notation System) software. See the Online Help for full copyright notice. EDEM EDEM Creator, EDEM Simulator, EDEM Analyst and Particle Factory are registered trademarks of DEM Solutions. All other brands or product names are the property of the respective owners. Page 2 of 10

3 Introduction This intermediate tutorial is directed at users who have covered introductory exercises, as the initial set-up of simulation is abbreviated and basic functionality not explained in detail. In case of any uncertainties or problems, refer to previous tutorials or EDEM Help section. This exercise explores further options of EDEM, focusing on the heat transfer capabilities. In this model heat is transferred through conduction between hot and cold particles. EDEM Heat Transfer feature is required to run this tutorial. The focus of this tutorial is on: Hertz-Mindlin with heat conduction contact model. Heat transfer through conduction between hot and cold particles. Introduction of Temperature Update as Particle Body Force interaction. Coloring particles according to the temperature. Adding text to the model in Viewer. Time = 1.42s Time = 14.92s 1. Start EDEM. 2. Go to File > Save As 3. Select a location on the local machine (e.g. C:\EDEM_Tutorials). 4. Enter a file name (e.g. Heat_Transfer_tutorial.dem) and click Save. 5. Remember to often press Save when setting up the simulation. Page 3 of 10

4 EDEM Creator: Setting up the model Step 1: Set the Global Model Parameters Choose the units 1. Go to Tools > Options menu and select the Units tab. 2. Change the following measurement units: Temperature to Kelvin (K) Length to mm Enter the model title and description 1. In the Globals tab, enter the title Heat Transfer in the Title field. 2. Enter a description in the Description field. Install the EDEM materials database If you have installed the materials database previously, ignore this step. 1. In Windows go to Start > DEM Solutions > EDEM 2.7 and select Install external libraries to My Documents. 2. When you navigate My Documents folder you will notice that new folder EDEM_2.7.0 was created. To make sure that the materials database is already available in your new simulation: 3. Go back to EDEM and navigate to: Tools > Options > File Locations. 4. In Materials Database section, click Browse button and go to EDEM_2.7.0 folder in My Documents. 5. Select materialsdb.ddb and click OK. Set the gravity and define the material 1. Check that Gravity is set to -9.81m/s 2 in the z-direction. 2. In the Materials section, click the Transfer button. The Material/Interactions Transfer dialog will appear. 3. Expand the Materials tree in the Materials database window and select medium-stiffness. 4. Click the left arrow to copy the material into your model. Click OK. 5. Rename this material to Plastic. Define the interactions between the materials 1. Select Plastic from the drop-down list at the top of the materials section. 2. Click the button in the Interaction section and when prompted choose Plastic to define interaction between particles made of the same material. 3. Leave the values as default. Page 4 of 10

5 Step 2: Define the Base Particles Particles are made up of one or more spherical surfaces. In this case the particle is represented by a single sphere. Create a new particle type 1. Click on the Particles tab in the Tabs pane. 2. Click the button to create a new particle type. 3. Click the button and rename the particle type Plastic_ball. 4. Set the Radius of the surface to 40 mm. 5. Set the Material to Plastic. 6. Click the Calculate Properties button and pick the Surfaces option. Step 3: Set the Contact Models Hertz-Mindlin with heat conduction contact model is used to represent the heat transfer between particles of different temperatures. Set the Heat Transfer model 1. Go back to Globals tab. 2. Select Particle to Particle from the Interaction pull-down in the Physics section. 3. Select Hertz-Mindlin (no slip) then click the button to remove it. 4. Click the button and select Hertz-Mindlin with heat conduction: 5. Click the configure button to set the Thermal Conductivity as follows: 6. Select Particle Body Force from the Interaction pull-down. 7. Click the button and select Temperature Update. 8. Click the configure button to set the Heat Capacity as follows: Page 5 of 10

6 Step 4: Define the Geometry In this exercise you do not need to import a CAD geometry as you will construct it in EDEM. Create a box 1. Click on the Geometry tab. 2. Click the button in the Sections part and choose Box. 3. Click the Box tab and set the specification as follows: Create the particle factory plate Particle factories are used to define where, when and how particles appear in a simulation. All factories must be based on a section of geometry (whether 'real' or 'virtual'). This defines the area in the model that produces the particles. 1. Click the button again to create a Polygon. 2. Click the button to rename it Factory_plate. 3. Click the Details tab and set the type to Virtual, since it is not a physical part of the machinery. 4. Click on the Polygon tab and set the specification as follows: Page 6 of 10

7 Step 5: Create the Particle Factories Two particle factories are needed in this simulation - one to produce hot particles and the other to produce cold particles. Both factories can be based on the same geometry, ie. a polygon created in previous section. Create the particle factories 1. Click on the Factories tab. 2. Click the button o create a new factory. 3. Click the button to rename it Hot_factory. 4. Set the Factory Type to dynamic. 5. Select Total Number and set the value to In the Generation Rate Section, select Target Number (per second) and set the rate to 10 particles/s. Set the hot factory s initial parameters 1. In the Parameters section, select the Factory_plate from the Section pulldown. 2. Set the Temperature to fixed then click the configure button to set a value of 400 K. Create the cold particle factory 1. Click the button again to create a new factory and Rename it Cold_Factory. 2. Set the Factory Type to dynamic. 3. Select Total Number and set the value to In the Generation Rate section, select Target Number (per second) and set the rate to 1 particles/s. 5. Set the Start Time to 1 s. Set the cold factory s initial conditions 1. In the Parameters section, select the Factory_plate from the Section pulldown. 2. Set the Temperature to fixed then click the configure button to set a value of 300 K. 3. Select File > Save. Page 7 of 10

8 EDEM Simulator: Run the Simulation 1. Click on the Simulator button on the toolbar. Step 1: Set the Time Options Set the time step 1. Set the Fixed Time Step lower box to s. It is approximately 29% of Rayleigh time step. To find out more about Rayleigh time step, refer to Appendix A: Estimating Simulation Time of the EDEM Help. Set the simulation time and grid options 1. In Simulation Time section, set the Total Time to 20s. 2. Set the Target Save Interval to 0.001s to specify write-out frequency. 3. Set the grid size to 3 Rmin. Step 2: Run the Simulation 1. Click the Start progress button at the bottom of the simulation window. 2. In Viewer Controls, click the Refresh Viewer button or enable Auto Update at any point to update the Viewer and see how the simulation is progressing. Page 8 of 10

9 EDEM Analyst: Analyzing the Results 1. Click on the Analyst button on the toolbar. Step 1: Configuring the Display Configure the geometry You need to modify the display of the geometry in order to be able to see the particles. 1. In Model tab, Set the Display Mode of the geometry to Filled and opacity to Click Apply. Step 2: Coloring Elements 1. Click the Coloring tab. 2. In the Attribute Coloring section, select Temperature as an Attribute. 3. Check the Show Legend box. 4. Set the Min and Max Values of temperature as follows: 5. Click Apply and watch the simulation. Step 3: Adding Labels 1. Go to the Viewer Controls section on the right of the Viewer. 2. Click the button in the Text area 3. Replace Message 1 with the label Initially Hot. 4. Set the text color to Red. 5. Enable the Position Text checkbox and place the label appropriately. 6. Repeat previous instructions to add a Initially Cold label in Blue font. 7. When finished, uncheck the Position Text box. Page 9 of 10

10 Step 4: Review the Simulation 1. In the Viewer Controls, set the Step Factor to Time of value 0.02 s. 2. Watch the simulation again. You will observe that a hot ball is created followed by two cold balls a second later. Note how heat is transferred over time between the three balls. The images below show two different time steps. You can modify the display further for your convenience. You may also extend the simulation time to establish when all the particles would reach the same temperature state. Page 10 of 10