def q_liq_top(rho_top_liq, L_septum, L_top):
    """
    Calculates the specific flow rate of the liquid for 1 m of drain septum
    Parameters
    ----------
    rho_top_liq : float
        The destiny of liquid at top of column, [kg/m**3]
    L_top : float
        The flow rate of liquid at top of column, [kg/s]
    L_septum : float
        The length of drain septum, [m]
    Returns
    -------
    q_liq_top : float
        The specific flow rate of the liquid for 1 m of drain septum at top of column, [m**2/s]
    References
    ----------
    Дытнерский, страница 239, формула 6.39
    """
    return L_top / (rho_top_liq * L_septum)