def d_enter_waste_cooler(W_mass, rho_waste, w_drift):
    """
    Calculates the tube's diameter of enter waste to waste cooler.
    Parameters
    ----------
    W_mass : float
        The mass flow rate of waste, [kg/s]
    rho_waste : float
        The density of liquid at boilling temperature, [kg/m**3]
    w_drift :float
        The speed of steam at the tube, [m/s]
    Returns
    -------
    d_enter_waste_cooler : float
        The tube's diameter of enter waste to waste cooler, [m]
    References
    ----------
    &&&
    """  
    return W_mass/(0,785*rho_waste*w_drift)