Mass and heat transfer at the outer surface of helical coils under single and two phase flow. (25th June 2016)

• Record Type: Journal Article
• Authors: Abdel-Aziz, M.H.; Nirdosh, I.; Sedahmed, G.H.
• Is Part Of: Applied thermal engineering. Volume 103(2016:Jun.)
• Page Start: 713
• Page End: 719
• Publication Date: 2016-06-25
• Subjects: Mass transfer -- Heat transfer -- Electrochemical reactor -- Catalytic reactor -- Two phase flow -- Helical coils; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2016.04.146
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: The work aims to develop reactors which need rapid temperature control. Mass and heat transfer at the outer surface of helical coils was studied experimentally. The experiments were conducted under gas sparing, single and two phase flow. Variables were helical tube diameter, physical properties, and gas and liquid velocity. Results verification in terms of natural convection and surface renewal mechanism was explained. Abstract: The mass transfer behavior of the outer surface of vertical helical coil was studied by the electrochemical technique under single phase flow, gas sparging and two phase flow. Variables studied were helical tube diameter, physical properties of the solution, solution velocity and superficial gas velocity. The mass transfer data were correlated by dimensionless equations. Mass transfer enhancement ratio in case of two phase flow ranged from 1.1 to 4.9 compared to single phase flow. Implication of the results for the design and operation of helical coil reactors used to conduct L–S exothermic diffusion controlled reactions which need rapid temperature control were outlined. In this case the inner coil surface will act as a cooler while the outer surface will act a reaction surface. Immobilized enzyme catalyzed biochemical reactions where heat sensitive materials may be involved represent an example for the reactions which can employ the helical coil reactor. Also the importance of the results in the design of and operation of diffusion controlled membrane processes which employ helical coil membrane was noted. In view of the analogy between heat and mass transfer the possibility of using the results in the design and operation of helical coil heat exchangers was highlighted.