fevereiro 2015 vol. 1 num. 2 - XX Congresso Brasileiro de Engenharia Química
Artigo - Open Access.
EFFECTIVE RADIAL DIFFUSIVITIES TO MODEL ENHANCED MASS AND HEAT TRANSFER IN LAMINAR FLOW REACTORS
Main features of a laminar flow reactor (LFR) are streamline flow and parabolic velocity profile. Consequently, heating and cooling are difficult and there is a large spread in the residence time distribution (RTD). Enhanced heat and mass transfer can be found in coils or corrugated tubes or in the presence of wall roughness, curves, pipe fittings or mechanical vibration. Modeling these cases can be complex because of the induced secondary flow. Objective of this work is to introduce this enhanced transport in the LFR model by means of effective radial diffusivities of heat and mass. Model validation experiments were conducted in a LFR with high wall relative roughness and curves. RTD experiments were compared with model simulations of tracer dispersion to obtain the mass diffusivity. Heat transfer experiments provided the effective thermal diffusivity. Tested fluids were a glycerin/water mixture (Newtonian) and a CMC solution (pseudoplastic). Model was successfully adjusted and parameters were correlated with Reynolds number for flow.
-  BARBA, A., RAINIERI, S.; SPIGA, M. Heat transfer enhancement in a corrugated tube. Int. Commun. Heat Mass Tran., 29(3), 313-322, 2002.
-  BERGLES, A.E.; JOSHI, S.D. Augmentation techniques for low Reynolds number in-tube flow. In: KAKAÇ, S., SHAH, R.K.; BERGLES, A.E. (Eds.), Low Reynolds Number Flow Heat Exchangers. Washington: Hemisphere, 1983.
-  CAREZZATO, A.; ALCANTARA, M.R.; TELIS-ROMERO, J.; TADINI, C.C.; GUT, J.A.W. Non-Newtonian heat transfer on a plate heat exchanger with generalized configurations. Chem. Eng. Technol., 30(1), 21-26, 2007.
-  CHHABRA, R.P.; RICHARDSON, J.F. Non-Newtonian Flow and Applied Rheology: Engineering Applications, 2nd ed. Butterworth-Heinemann, 2008.
-  DANTAS, J.A.T.A.; GUT, J.A.W.; PEGORARO, P.R. Determination of the effective radial mass diffusivity in tubular reactors under non-Newtonian laminar flow using residence time distribution data. Int. J. Heat Mass Tran., 71, 18-25, 2014.
-  FOGLER, H.S. Elements of Chemical Reaction Engineering, 4th ed. Upper Saddle River: Prentice Hall, 200
-  KECHICHIAN, V.; CRIVELLARI, G.P.; GUT, J.A.W.; TADINI, C.C. Modeling of continuous thermal processing of a non-newtonian liquid food under diffusive laminar flow in a tubular system. Int. J. Heat Mass Tran., 55(21-22), 5783-5792, 2012.
-  LEVENSPIEL, O. The Chemical Reactor Omnibook. Corvallis: OSU, 1989.
-  PIMENTA, T.A.; CAMPOS, J.B.L.M., Heat transfer coefficients from Newtonian and non-Newtonian fluids flowing in laminar regime in a helical coil. Int. J. Heat Mass Tran., 58(1-2), 676-690, 2013.
-  SOLANO, J.P.; HERRERO, R.; ESPÍN, S.; PHAN, A.N.; HARVEY, A.P. Numerical study of the flow pattern and heat transfer enhancement in oscillatory baffled reactors with helical coil inserts, Chem. Eng. Res. Des., 90(6), 732-742, 2012.
DANTAS, J. A. T. A.; MORAIS, A. O.; GUT, J. A. W.; "EFFECTIVE RADIAL DIFFUSIVITIES TO MODEL ENHANCED MASS AND HEAT TRANSFER IN LAMINAR FLOW REACTORS", p. 6313-6320 . In: Anais do XX Congresso Brasileiro de Engenharia Química - COBEQ 2014 [= Blucher Chemical Engineering Proceedings, v.1, n.2].
São Paulo: Blucher,
ISSN 2359-1757, DOI 10.5151/chemeng-cobeq2014-1822-17375-138581
últimos 30 dias | último ano | desde a publicação