def B_boiler(rho_W_boil, rho_W_vapor, sigma_W_boil, r_W_boil, Cw_boil, mu_W_boil, lyambda_W_boil):
    """
    Calculates the coefficent B of boiler.
    Parameters
    ----------
    lyambda_W_boil : float
        The thermal conducivity of waste at the boilling temperature, [W / (m * degrees celcium)]
    rho_W_boil : float
        The destiny of waste at boilling the temperature, [kg / m**3]
    rho_W_vapor : float
        The destiny of vapor at boilling the temperature, [kg / m**3]
    sigma_W_boil : float
        The surface tension of waste at the boilling temperature, [N/m]
    r_W_boil : float
        The heat vaporazation of waste at the boilling temperature, [N/m]    
    Cw_boiler : float
        The heat capacity of waste at the boiling temperature, [J/(kg * degrees C)]
    mu_W_boiler : float
        The viscocity of waste at the boiling temperature, [Pa/s]      
    Returns
    -------
    B_boiler : float
        The coefficent B of boiler, [dismensionless]
    References
    ----------
    Дытнерский, формула 2.28, стр.54
    """                  
    return 780 * lyambda_W_boil^(1.3) * rho_W_boil^(0.5) * rho_W_vapor^(0.06) / (sigma_W_boil^(0.5) * r_W_boil^(0.6) * rho_W_vapor^(0.66) * Cw_boil^(0.3) * mu_W_boil^(0.3))