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    计算出现负相率和负湍动能

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    • C
      Caijinjin last edited by

      1b12af59-4375-480a-bb3b-de5d017006aa-image.png
      如图,是一个搅拌釜内的液固两相流,用的twoPhaseEulerFoam,计算过程中逐渐发散,出现了很多负值,请问这个可能是什么原因导致的?对网格进行了质量检查,网格为非结构网格,这个非正交性的值是偏大还是正常范围?
      d5838f8d-b15f-4118-8771-7b8350ed29e5-image.png
      fvSolution设置为:(为了不求解温度,我将h/e的迭代数设为0,是否对计算有影响?)

      solvers
      {
          "alpha.*"
          {
              nAlphaCorr      1;
              nAlphaSubCycles 2;
      
              smoothLimiter   0.1;
      
              implicitPhasePressure yes;
              solver          smoothSolver;
              smoother        symGaussSeidel;
              tolerance       1e-9;
              relTol          0;
              minIter         1;
          }
      
          p_rgh
          {
              solver          GAMG;
              smoother        DIC;
              tolerance       1e-8;
              relTol          0;
          }
      
          p_rghFinal
          {
              $p_rgh;
              relTol          0;
          }
      
          "U.*"
          {
              solver          smoothSolver;
              smoother        symGaussSeidel;
              tolerance       1e-5;
              relTol          0;
              minIter         1;
          }
      
          "(h|e).*"
          {
              solver          smoothSolver;
              smoother        symGaussSeidel;
              // tolerance       1e-6;
              relTol          0;
              minIter         0;
              maxIter         0;
          }
      
          "Theta.*"
          {
              solver          smoothSolver;
              smoother        symGaussSeidel;
              tolerance       1e-6;
              relTol          0;
              minIter         1;
          }
      
          "(k|epsilon).*"
          {
              solver          smoothSolver;
              smoother        symGaussSeidel;
              tolerance       1e-5;
              relTol          0;
              minIter         1;
          }
      }
      
      PIMPLE
      {
          nOuterCorrectors 3;
          nCorrectors      1;
          nNonOrthogonalCorrectors 0;
      }
      
      relaxationFactors
      {
          equations
          {
              ".*"            1;
          }
      }
      

      希望各位大佬帮忙解答,感谢!

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      • C
        Caijinjin last edited by

        另外附上我的离散格式,出现负值是否因为离散格式设置错误?未包含有界限制?

        ddtSchemes
        {
            default     Euler;
        }
        
        gradSchemes
        {
            default     Gauss linear;
        }
        
        divSchemes
        {
            default                         none;
        
            "div\(phi,alpha.*\)"            Gauss vanLeer;
            "div\(phir,alpha.*\)"           Gauss vanLeer;
        
            "div\(alphaRhoPhi.*,U.*\)"      Gauss limitedLinearV 1;
            "div\(phi.*,U.*\)"              Gauss limitedLinearV 1;
        
            "div\(alphaRhoPhi.*,(h|e).*\)"  Gauss limitedLinear 1;
            "div\(alphaRhoPhi.*,K.*\)"      Gauss limitedLinear 1;
            "div\(alphaPhi.*,p\)"           Gauss limitedLinear 1;
        
            div(alphaRhoPhi.particles,Theta.particles) Gauss limitedLinear 1;
        
            "div\(alphaRhoPhi.*,(k|epsilon).*\)"  Gauss limitedLinear 1;
        
            div((((alpha.water*thermo:rho.water)*nuEff.water)*dev2(T(grad(U.water))))) Gauss linear;
        
            div((((thermo:rho.particles*nut.particles)*dev2(T(grad(U.particles))))+(((thermo:rho.particles*lambda.particles)*div(phi.particles))*I)))  Gauss linear;
        }
        
        laplacianSchemes
        {
            default     Gauss linear uncorrected;
            bounded     Gauss linear uncorrected;
        }
        
        interpolationSchemes
        {
            default     linear;
        }
        
        snGradSchemes
        {
            default     uncorrected;
            bounded     uncorrected;
        }
        
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        • 李东岳
          李东岳 管理员 last edited by

          openfoam几,用新的openfoam比较好
          这个求解器对网格之类比较敏感,最好先上迎风格式

          CFD课程 改成线上了 http://dyfluid.com/class.html
          CFD高性能服务器 http://dyfluid.com/servers.html

          C 1 Reply Last reply Reply Quote
          • C
            Caijinjin @李东岳 last edited by

            @李东岳 用的of7,那请问我这个网格的非正交性算大还是正常,如果网格质量不好那使用reactingTwoPhaseEulerFoam来计算是否会网格的敏感性有所改善?还是用最新的of9里面的multiphaseEulerFoam会好一点?

            李东岳 1 Reply Last reply Reply Quote
            • 李东岳
              李东岳 管理员 @Caijinjin last edited by

              @caijinjin multiphaseEulerFoam > reactingTwoPhaseEulerFoam > twoPhaseEulerFoam

              CFD课程 改成线上了 http://dyfluid.com/class.html
              CFD高性能服务器 http://dyfluid.com/servers.html

              C 1 Reply Last reply Reply Quote
              • C
                Caijinjin @李东岳 last edited by

                @李东岳 好的,谢谢东岳老师

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