STUDY OF THE COOLING EFFICIENCY OF FURNACE FAN’S SHAFT EQUIPPED WITH DEVICES OF ROD TYPE

 The design of the air cooling device for the furnace fan’s shaft of  rod type of three standard sizes is proposed. During the experiments at the experimental stand, the convective heat transfer from the surface of  these devices to the environment at a different shaft rotation frequency  was obtained critically. It was established that in the range of variation  of the relative length of the rods from 3.3 to 6.1, a regime close to the  self-similar mode takes place, where the heat transfer from their surface can be described by a universal dependence. In the range of variation of the relative length of the rods from 6.1 to 8.6, the experimental  data are generalized in the form of a power law with a proportionality  coefficient that depends on the ratio of the shaft diameter to the outer  diameter of the device. The least coefficient of heat transfer from the external surface was found in ST-346 with the largest outside diameter  and, correspondingly, the longest rods, which is apparently due to the  fact that in the process of heat transfer from the shaft to the environment, the limiting heat exchange section is the heat supply by heat  conduction along of the rods axis. The highest heat transfer coefficient  under comparable conditions is observed in ST-286 with medium rods,  where the heat supply is more balanced by thermal conductivity along  the rods and its removal from their external surfaces by convection to  the environment. When comparing the data obtained with CT-286 and  CT-220, it was found that at the same shaft rotation frequency, the heat  transfer coefficient over the surface of ST-286 is about 15–20  %, which  is associated with a decrease in intensity of air blowing of shortened  rods of ST-220 due to the decrease in their average linear speed of  movement along the circumference. From the analysis of the obtained  results, it follows that the most effective in comparable conditions is  the device with a maximum diameter of 346 mm, where the dissipated  thermal power in the steady state is 1.1 times higher than that of the  device with a diameter of 286 mm and 2.0 times greater than for devices with a diameter of 220 mm. The obtained materials can be used  in the design of heating and thermal furnaces using forced coolant circulation. 

1. Apterman V.N., Tymchak V.M. Protyazhnye pechi [Continuous furnaces]. Moscow: Metallurgiya, 1969, 320 p. (In Russ.).

2. Druzhinin G.M., Ashikhmin A.A., Maslov P.V., Popov A.B., Loshkarev N.B., Galkin S.A. Furnace with a hybrid heating system. Steel in Translation. 2015, vol. 45, no. 3, pp. 216–220.

3. Zainullin L.A., Kalganov M.V., Kalganov D.V., Loshkarev N.B.,  Fatkhutdinov A.R., Pugin A.I. Furnace electric heaters with radiantconvective heat transfer. Steel in Translation. 2015, vol. 45, no. 3,  pp. 221–223.

4. Mikheev M.A., Mikheeva I.M. Osnovy teploperedachi [Fundamentals of heat transfer]. Moscow: Energiya, 1977, 343 p. (In Russ.).

5. Kazantsev E.I. Promyshlennye pechi [Industrial Furnaces]. Moscow: Metallurgiya, 1975, 367p. (In Russ.).

6. Zainullin L.A., Kalganov M.V., Kalganov D.V., Spirin N.A. Using centrifugal fans in the cooling of convective furnaces. Steel in Translation. 2015, vol. 45, no. 3, pp. 224–225.

7. Solomakhova T.S., Chebysheva K.V . Tsentrobezhnye ventilyatory: spravochnik [Centrifugal fans: Handbook]. Moscow: Mashinostroenie, 1980, 175 p. (In Russ.).

8. Bloom W. Jet heat reparation of waste furnace gases on strip lines.  Iron and Steel Engineer. 1979, no. 12, pp. 32–37.

9. Martin H. Heat and mass transfer between impinging gas jets and  solid surfaces. Advances in Heat Transfer. 1977, vol. 13, pp. 1–60.

10. Launder B.E., Rodi W. The turbulent wall jet. Prog. Aerospace Science. 1981, vol. 19, pp. 81–128.

11. Kuz’min I.I., Zubkov S.V., Lyzhin Yu.A. Improving of the circulation  fan design in bell furnaces. Stal’. 2007, no. 8, pp. 89–91. (In Russ.).

12. Sultanov N.L., Mironenkov E.I., Zhirkin Yu.V. Managing of thermal state of bearings on cold rolling tandem-mill 2000 of ММК  ОМО. Stal’. 2014, no. 4, pp. 71–73. (In Russ.).

13. Kutlubaev I.M., Matsko E.Yu., Usov I.G. Improvement of cooling  of rolled products. Stal’. 2015, no. 8, pp. 44–50. (In Russ.).

14. Demin K.K., Parshikov S.F. Improvement of the tape cooling technologies after bright annealing in a one-foot bell furnace. Stal’.  2008, no. 4, p. 69. (In Russ.).

15. Zareba S., Wolff A., Jelali M. Mathematical modelling and parameter identification of a stainless steel annealing furnace. Simulation Modelling Practice and Theory. 2016, vol. 60, pp. 15–39.

16. Strommer S., Niederer M., Steinboeck A., Kugi A. A mathematical model of a direct-fired continuous strip annealing furnace. International Journal of Heat and Mass Transfer. 2014, vol. 69,   pp.  375–389.

17. Feng H.J., Chen L.G., Xie Z.H., Sun F.R. Constructal designs for  insulation layers of steel rolling reheating furnace wall with convective and radiative boundary conditions. Applied Thermal Engineering. 2016, vol. 100, pp. 925–931.

18. Blaszczuk A., Nowak W. Heat transfer behavior inside a furnace  chamber  of  large-scale  supercritical  CFB  reactor.  International Journal of Heat and Mass Transfer. 2015, vol. 87, pp. 464–480.

19. Feng H.J., Chen L.G., Xie Z.H., Sun F.R. Constructal entransy optimizations for insulation layer of steel rolling reheating furnace wall  with convective and radiative boundary conditions. Chinese Science Bulletin. 2014, vol. 59, pp. 2470–2477.

20. Emadi A., Saboonchi A., Taheri M., Hassanpour S. Heating characteristics of billet in a walking hearth type reheating furnace. Applied Thermal Engineering. 2014, vol. 63, pp. 396–405. 

21. Prieto M.M., Fernandez F.J., Rendueles J.L. Development of stepwise thermal model for annealing line heating furnace. Ironmaking & Steelmaking. 2005, vol. 32, pp. 165–170. 

22. Kim Y.D., Kang D.H., Kim W.S. Experimental and numerical studies on the thermal analysis of the plate in indirectly fired continuous  heat treatment furnace. Journal of Mechanical Science and Technology. 2009, vol. 23, pp. 631–642.

23. Zainullin L.A., Kalganov M.V., Kalganov D.V . Investigation of  cooling efficiency of the rotating high temperature furnace fan. Izvestiya VUZov. Chernaya metallurgiya = Izvestiya. Ferrous Metallurgy. 2015, no. 9, pp. 662–666. (In Russ.).