63        temperature = clamp(temperature, 1e-9, 500.0); 
 
   64        pressure = clamp(pressure, 0.0, 1e8); 
 
   70        constexpr Scalar M_x = 1e3*Xylene::molarMass(); 
 
   71        constexpr Scalar M_w = 1e3*H2O::molarMass(); 
 
   72        constexpr Scalar Tb_x = 412.9;        
 
   73        constexpr Scalar Tb_w = 373.15;       
 
   74        constexpr Scalar V_B_w = 18.0;                
 
   75        const Scalar  sigma_w = 1.18*pow(V_B_w, 0.333);     
 
   76        constexpr Scalar  T_scal_w = 1.15*Tb_w;     
 
   77        constexpr Scalar V_B_x = 140.4;       
 
   78        const Scalar sigma_x = 1.18*pow(V_B_x, 0.333);     
 
   79        const Scalar sigma_wx = 0.5*(sigma_w + sigma_x);
 
   80        constexpr Scalar T_scal_x = 1.15*Tb_x;
 
   81        const Scalar T_scal_wx = sqrt(T_scal_w*T_scal_x);
 
   84        Scalar T_star = temperature/T_scal_wx;
 
   85        T_star = max(T_star, 1e-5); 
 
   87        const Scalar Omega = 1.06036/pow(T_star, 0.1561) + 0.193/exp(T_star*0.47635)
 
   88            + 1.03587/exp(T_star*1.52996) + 1.76474/exp(T_star*3.89411);
 
   89        const Scalar  B_ = 0.00217 - 0.0005*sqrt(1.0/M_w + 1.0/M_x);
 
   90        const Scalar Mr = (M_w + M_x)/(M_w*M_x);
 
   91        const Scalar D_wx = (B_*pow(temperature,1.6)*sqrt(Mr))
 
   92                           /(1e-5*pressure*power(sigma_wx, 2)*Omega);