International Scientific Journal


The moisture content of oil-filled transformers insulation paper that is a cellulose-containing material comprises 8% to 10% of moisture by weight at ambient temperature and it is highly important to decrease the moisture content for effective use of a transformer. Vapor phase drying is more effective method for drying the insulation paper of the transformer as compared with other conventional methods due to less cycle time and energy consumption. The purpose of this paper is to design a solvent operated drying chamber in which drying of the insulation paper of oil filled transformer carried out. The approach of the present paper is to develop a numerical model to reduce the cycle time of the drying process. The unsteady flow, heat, and mass transfer phenomena were simulated by using CFD solver. Theoretical studies and a numerical model were conducted over thermal calculation in the drying process using solvent at different pressures. Theoretical calculations were used to validate the numerical model. Drying chamber was optimized by using response surface methodology. The result of the study showed that drying cycle time was decreased almost 14.3% with the new design. Furthermore, when the solvent was used instead of air as a heat carrier, the drying cycle time was reduced.
PAPER REVISED: 2019-02-15
PAPER ACCEPTED: 2019-03-05
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THERMAL SCIENCE YEAR 2020, VOLUME 24, ISSUE Issue 3, PAGES [2125 - 2135]
  1. Arshad, M., Islam, S., Significance of cellulose power transformer condition assessment, IEEE Transactions on Dielectrics and Elecrtical Insulation, 18 (2011), 5, pp. 1591-1598.
  2. Kudra, T., Mujumdar, A., Advanced Drying Technologies, Taylor & Francis Group, NewYork, ,USA, 2009.
  3. Bangar, A. et al., Comparative analysis of moisture removing processes from transformer which are used to increase its efficiency, Global Journal of Research in Engineering , 12 (2012), 5, pp. 7-12.
  4. Orikasa, T. et al., Impacts of hot air and vacuum drying on the quality attributes of kiwifruit slices, Journal of Food engineering , 125 (2014), pp. 51-58.
  5. Padmanabhan, S. et al., Synthesis of silica cryogel-glass fiber blanket by vacuum drying, Ceramics International , 42 (2016), 6, pp. 7216-7222.
  6. Patil, V. et al., Optimizationof the spray-drying process for developing guava powder using response surface methodology, Powder Technology , 253 (2014), pp. 230-236.
  7. Atalar, I., Dervisoglu, M., Optimization of spray drying process parameters for kefir powder using respons surface methodology, LWT - Food Science and Technology , 60 (2015), 2, pp. 751-757.
  8. Erbay, Z. et al., Optimization of spray drying process in cheese powder production, Food and Bioproducts Processing, 93 (2015), pp. 156-165.
  9. Cho, J. et al., Large-scale production of fine-sized Zn2SiO4:Mn phosphor microspheres eith a dense structure and good photoluminescence properties by a spray-drying process, Royal Society of Chemistry , 4 (2014), pp. 43606-43611.
  10. Son, M. et al., Study of Co3O4 mesoporous nanosheets propared by a simple spray-drying mprecess and their electrochemical properties as anode material for lithium secondary batteries, Elecrochimica Acta , 116 (2014), pp. 44-50.
  11. Jeon, K. et al., Elecrochemical properties of MnS-C and MnO-C composite powders prepared via spray drying process, Journal of Powder Sources , 295 (2015), pp. 9-15.
  12. Park, G. et al., Large-scale production of MoO3-reduced graphene oxide powders with superior lithium storage properties by spray-drying process, Electrochimica Acta , 173 (2015), pp. 581-587.
  13. Swassisevi, T. et al., Optimizaion of a drying process using infrared-vacuum drying of Cavendish banana slices, Songklanakarin Journal of Science and Technology, SJST, 29 (2007), 3, pp. 809-816.
  14. Giri, S.K., Prasad, S. Optimization of microwave-vacuum drying of button mushrooms using response surface methodology, Drying Technology, 25 (2007), 5, pp. 901-911.
  15. Han, Q.H. et al., Optimization of process parameters for microwave vacuum drying of apple slices using response surface method, Drying Technology, 28 (2010), 4, pp. 523-532.
  16. Sturm, B. et al., Optimizing the drying parameters for hot-air-dried apples, Drying Technology, 30 (2012), 14, pp. 1570-1582.
  17. Pu, Y.Y., & Sun, D.W., Combined hot-air and microwave-vacuum drying for improving uniformity of mango slices based on hyperspectral imaging visualization of moisture content distribution, Biosystems Engineering, 156 (2017), pp. 108-119.
  18. Silva, P.I. et al., Parameter optimization for spray-drying microencapsulation of jaboticaba (myrciaria jaboticaba) peel extracts using simultaneous analysis of responses, Journal of Food Engineering, 117 (2013), pp. 538-544.
  19. Kumar, D. et al., Optimization of microwave-assisted hot air drying conditions of okra using response surface methodology, Journal of Food Science and Technology, 51 (2014), 2, pp. 221-232.
  20. Siddiqui, M. et al., Vapor Phase Drying for Moisture Removal from Transformer Coil Insulation, Intrnational Journal of Scientific & Engineering Research, IJSER , 8 (2017), 4, pp. 20-24.
  21. ***, Shell, (accessed 28 May 2018).
  22. Incropera, F. et al., Fundementals of heat and mass transfer (6th Edition ed.), John Wiley & Sons, Danvers, USA, 2007.

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