def Re_intube_waste(W_mass, z_way_waste, d_inner_waste, n_pipe_waste, mu_waste_avrg):
    """
    Calculates the Reynold criterion.
    Parameters
    ----------
    F_mass : float
        The mass flow rate of feed [kg/s]
    z_way_waste : float
        The number of ways in heat exchanger [dimensionless]
    d_inner_waste : float
        The diametr of inner pipe, [m]
    n_pipe_waste : float
        The number of pipes in heat exchanger, [dimensionless]
    mu_waste_avrg : float
        The mix viscocity of liquid, [Pa/s]
    Returns
    -------
    Re_intube_waste : float
        The Reynold criterion in tube(waste), [dimensionless]
    References
    ----------
    &&&&&&
    """         
    return 0.785 * W_mass * z_way_waste / (d_inner_waste * n_pipe_waste * mu_waste_avrg)