Skip to content
GitLab
Projects Groups Topics Snippets
  • /
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
    • Contribute to GitLab
  • Register
  • Sign in
  • openfoam openfoam
  • Project information
    • Project information
    • Activity
    • Labels
    • Members
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributor statistics
    • Graph
    • Compare revisions
  • Issues 454
    • Issues 454
    • List
    • Boards
    • Service Desk
    • Milestones
  • Merge requests 14
    • Merge requests 14
  • Deployments
    • Deployments
    • Releases
  • Wiki
    • Wiki
  • Activity
  • Graph
  • Create a new issue
  • Commits
  • Issue Boards
Collapse sidebar
  • Development
  • openfoamopenfoam
  • Issues
  • #2369
Closed
Open
Issue created Feb 18, 2022 by PG@minecraftgp

Energy not conserved - a sealed room heated up using buoyantPimpleFoam solver with boussinesq equation of state

The case is a sealed room with 80W output heat source. The problem I met is that the total enthalpy increase inside the whole room in 1s is 75J. A buoyantPimpleFoam solver with boussinesq equation of state is used for the case.

The setting of the heat source is to use scalarSemiImplicitSource, which used part of the room air as a cellSet heat source. The code is shown as follow heat1 { type scalarSemiImplicitSource; enabled true; active true; scalarSemiImplicitSourceCoeffs { selectionMode cellSet; cellSet heat1; volumeMode absolute; injectionRateSuSp { h { Su table ( (0 80) ); Sp 0.0; } } } }

To measure the enthalpy increase inside the room, a swak4Foam code is used as follow, where 298.15 is the reference temperature T0, 1000 is the mass heat capacity Cp, and vol() is the volume for each cell. T_volSum_room { name T_volSum_room; type swakExpression; valueType cellSet; libs ("libsimpleSwakFunctionObjects.so" ); outputControlMode timeStep; outputInterval 10; writeStartTime no; setName room; expression "(T-298.15)*1000*vol()*rho"; autoInterpolate true; accumulations (sum); verbose true; } The case folder is in the attachment. To reproduce this issue just simple extract the zip file, entering the folder, execute ./Allrun.

Once the case finishes runing, open the postProcessing/swakExpression_T_volSum_room/0/T_volSum_roomOnce and will see time vs enthalpy, an enthalpy increase rate can be calculated based on that and it is 6-7% less than 80W heat source input.

Regards, Pu

sealedRoom.zip

Regard Pu

Assignee
Assign to
Time tracking