Adding the Dewes correlation

[ggmirandac]

Hi,

I added the dewes correlation. The code added is:

def kla_bubcol_Dewes(V_g, mu_l, rho_g):
    """
    Returns the KLa coefficient for a bubble column reactor based on the Dewes & Schumpe (1997) correlation.
    -------
    Parameters:
    V_g: float
        Superficial gas velocity, [m/s]
    mu_l: float
        Viscosity of the liquid, [mPa.s]
    rho_g: float
        Density of the gas, [kg/m^3]
    -------
    References: 
    Dewes, I., & Schumpe, A. (1997). 
        Gas density effect on mass transfer in the slurry bubble column. 
        Chemical Engineering Science, 52(21–22), 4105–4109. https://doi.org/10.1016/S0009-2509(97)00252-2
    -------
    Notes:
    This correlation is valid under the following range of values:
    D_c: 0.115 m -> Diameter of the column [m]
    H_l: 1.37 m -> Liquid height in the column [m]
    V_g: 0.01 - 0.08 m/s -> Superficial gas velocity [m/s]
    mu_l: 1.35 - 583 mPa.s -> Viscosity of the liquid [mPa.s]
    rho_g: 0.4 - 18.8 kg/m^3 -> Density of the gas [kg/m^3]
    """

    kla = V_g**0.90 * mu_l**(-0.55) * rho_g**0.46
    return kla