def evap_volume_OILTRANS(k, area, p_oil, molar_v, T, molar_fraction = 1,
                         R = 8.314):
    """
    Return the evaporated fraction by unit of time [/s]
    source : (Berry et al., 2012)

    Parameters
    ----------
    k : mass transsfert coefficent [m/s]
    area : Area [m²]
    p_oil : Vapor pressure of the hydrocarbon [Pa]
    molar_v : Molar volume [m³/mol]
    T : Temperature [K]
    molar_fraction : Molar fraction, can be other than 1 if not pure
    R : Perfect gas constant, the default is 8.314 [J/mol K]


    """
    return (k * area * p_oil * molar_v * molar_fraction) / (R * T)