perfectFuild里面气体体积常数R的疑惑



  • 各位前辈好!

    自己目前研究了一下各种状态方程,对于perfectFluid里面的rho_0和R需要用户在thermophysicalProperties.water子字典里面设置的,参考openfoam自带的case里面的设置,发现R的取值为7255或者3000 J/(kg.K),

    case1:

    tutorials\multiphase\compressibleMultiphaseInterFoam\laminar\damBreak4phase\constant
    
    thermoType
    {
        type            heRhoThermo;
        mixture         pureMixture;
        transport       const;
        thermo          hConst;
        equationOfState perfectFluid;
        specie          specie;
        energy          sensibleInternalEnergy;
    }
    
    mixture
    {
        specie
        {
            nMoles      1;
            molWeight   18.0;
        }
        equationOfState
        {
            R           7255;
            rho0        1027;
        }
    //剩下代码忽略
    

    case2地址:

    \tutorials\multiphase\compressibleInterDyMFoam\ras\sloshingTank2D\constant
    
    thermoType
    {
        type            heRhoThermo;
        mixture         pureMixture;
        transport       const;
        thermo          hConst;
        equationOfState perfectFluid;
        specie          specie;
        energy          sensibleInternalEnergy;
    }
    
    mixture
    {
        specie
        {
            nMoles      1;
            molWeight   18.0;
        }
        equationOfState
        {
            R           3000;
            rho0        1027;
        }
    

    我现在不太明白,perfectFluid里面的R的设置参考什么呢?3000和7255是怎么来的呢??虽然对于液体来说,可能R差了1个量级对液体密度的影响并不是很大吧



  • perfectFluid的计算公式是$\rho=1027+\frac{101325}{R\cdot 300}$,所以R,3000,甚至30000都对$\rho$影响很小



  • 谢谢东岳老师指点,我刚刚测试过在空化流里面 R设置为7255或者3000之类的数值 对最后结果确实影响很小:chitang:


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