1 / 22

Transient Thermal Analysis

Workshop 6.2. Transient Thermal Analysis. Workshop 6.2 - Goals. In this workshop, we will analyze the electrically heated base typical of consumer steam irons like the one shown below. Workshop 6.2 - Assumptions. Assumptions:

ezeiger
Download Presentation

Transient Thermal Analysis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Workshop 6.2 Transient Thermal Analysis

  2. Workshop 6.2 - Goals • In this workshop, we will analyze the electrically heated base typical of consumer steam irons like the one shown below. August 26, 2005 Inventory #002266 WS6.2-2

  3. Workshop 6.2 - Assumptions Assumptions: • The heating element contacts and transfers heat to the base using the pattern shown here • Upon initial startup a heat flux of 0.001 W/mm2 is applied until a steady state is reached • Heating follows a 30 second step cycle of 0 to 0.003 W/mm2 after steady state is reached • The analysis will begin with the steady state solution and proceed through the cyclic loading described above August 26, 2005 Inventory #002266 WS6.2-3

  4. Workshop 6.2 - Start Page • From the launcher start Simulation. • Choose “Geometry > From File . . . “ and browse to the file “Iron.x_t”. • When DS starts, close the Template menu by clicking the ‘X’ in the corner of the window. August 26, 2005 Inventory #002266 WS6.2-4

  5. Workshop 6.2 - Preprocessing • Change the part material to “Polyethylene”: • Highlight “Part1” • In the Detail window “Material” field “Import . . .” • “Choose” material “Stainless Steel” 1 2 3 4 • Set the working units to (mm, kg, N, C, s, mV, mA) “Tools > Units” menu choose August 26, 2005 Inventory #002266 WS6.2-5

  6. Workshop 6.2 - Environment • Select surface representing the heating element on the face of the iron • “RMB > Insert > Heat Flux”. • Set “Magnitude” field to 0.001 W/mm2 5 6 7 August 26, 2005 Inventory #002266 WS6.2-6

  7. 9 12 10 11 . . . Workshop 6.2 - Environment • Select the bottom surface (opposite the heat flux side) and 6 side surfaces of the iron (7 faces) • “RMB > Insert > Convection” • Change to “Temperature Dependent” • Choose “Import” in the correlation field • Select “Stagnant Air – Vertical Planes1” • Set ambient temperature to 20 deg. C 8 13 August 26, 2005 Inventory #002266 WS6.2-7

  8. 18 17 . . . Workshop 6.2 - Environment • Select the 2 surfaces surrounding the heated surface • “RMB > Insert > Convection” • Change to “Temperature Dependent” • Choose “Import” in the correlation field • Select “Stagnant Air – Vertical Planes” • Set ambient temperature to 40 deg. C 14 15 16 August 26, 2005 Inventory #002266 WS6.2-8

  9. Workshop 6.2 - Solution • Add temperature and total heat flux results. • Highlight the Solution branch. • “RMB > Insert > Thermal > Temperature”, repeat for total heat flux • Solve 20 21 22 August 26, 2005 Inventory #002266 WS6.2-9

  10. Workshop 6.2 - Results • A review of the results shows the maximum steady state temperature is approximately 51.7 degrees C • The worksheet view of the environment shows that an energy balance has been achieved • Convection1 + Convection2 ≈ 5.2 W • Applied Load = 0.001W/mm2 * Area • Area ≈ 5276 mm August 26, 2005 Inventory #002266 WS6.2-10

  11. 23 Workshop 6.2 – Transient Solution • Highlight the “Temperature” result, RMB > “Generate Transient Environment with Initial Condition” • The result is, the steady state environment is duplicated and the new branch automatically setup as a thermal transient run • Notice the new branch contains an “initial condition” branch and a “transient settings” branch August 26, 2005 Inventory #002266 WS6.2-11

  12. 24 25 Workshop 6.2 – Transient Setup • Begin the transient setup by specifying an end time of 180 seconds for the analysis in the toolbar • Inspection of the initial condition details shows no action is required. The steady state (non-uniform) temperature result from the “Environment” branch is mapped to the transient branch August 26, 2005 Inventory #002266 WS6.2-12

  13. 26 27 28 . . . Workshop 6.2 - Transient Setup • Highlight “Heat Flux” in the Thermal Transient branch • In the heat flux detail change “Define As” to “Load History” • In the “History Data” field choose “New Load History . . . “ August 26, 2005 Inventory #002266 WS6.2-13

  14. . . . Workshop 6.2 - Transient Setup • The Engineering Data application will open and a new “Heat Flux vs. Time” chart/graph will be created • Enter the time and load data as shown on the next page August 26, 2005 Inventory #002266 WS6.2-14

  15. . . . Workshop 6.2 - Transient Setup • Enter time and load information as described in the problem statement • 30 second increments • 0.003 W/mm2 Heat Flux 29 August 26, 2005 Inventory #002266 WS6.2-15

  16. 30 . . . Workshop 6.2 - Transient Setup • Highlight the “Transient Settings” branch • Toggle off all items but “Heat Flux” in the “Visible” and “Active” columns of the Timeline Legend Control Notice the automatic time steps are based on the end time: Initial = ET/100, Min = ET/1000, Max = ET/10 Leave time steps as default August 26, 2005 Inventory #002266 WS6.2-16 31

  17. . . . Workshop 6.2 - Transient Setup • Toggling off all but the heat flux allows easier inspection of the timeline chart in this case • Since the heat flux is the only load defined as a “non-constant” it will have the only influence on the placement of the automatic step resets Reset points As expected, each reset point coincides with an inflection point on the load history August 26, 2005 Inventory #002266 WS6.2-17

  18. 32 Workshop 6.2 - Transient Results • Solve the thermal transient branch • When the solution is complete, results can be reviewed just as with steady state solutions • Highlight the quantity of interest to plot 33 August 26, 2005 Inventory #002266 WS6.2-18 31

  19. 34 35 . . . Workshop 6.2 - Transient Results • To review results from specific time points, LMB in the timeline chart to locate the time of interest • RMB > Retrieve Results August 26, 2005 Inventory #002266 WS6.2-19

  20. . . . Workshop 6.2 - Transient Results • Notice, when a new time point is selected in the time line, the result detail is displayed in red until the results matching the time selection are retrieved • Plotting the “Global Maximum” temperature from the Solution Information branch shows the model has not reached a cyclic equilibrium August 26, 2005 Inventory #002266 WS6.2-20

  21. . . . Workshop 6.2 - Transient Results • Using the Probe Tool allows individual parts of the model to be evaluated over time • Multiple Probes can be plotted on the same graph August 26, 2005 Inventory #002266 WS6.2-21 Multiple Probes Single Probe

More Related