Operation Stability Enhancement in Once-Through Micro Evaporators
Equipment miniaturisation offers several opportunities such as an increased surface-to-volume ratio and higher heat transfer coefficients. However, moving towards small-diameter channels demands extra attention to fouling, reliability and stable operation of the system. The present investigation explores possibilities to enhance the stability of the once-through micro evaporator by reducing its flow boiling induced pressure fluctuations. Experimental comparison shows that the measured reduction factor approaches a theoretically derived value. Pressure fluctuations are reduced by a factor of ten in the solid conical channel and a factor of 15 in the porous conical channel. This presumably leads to less backflow and therefore to a better flow control.
[1] C.M. Rops, L.F.G. Geers, J. Westerweel, "Explosive bubble growth during flow boiling in micro-channels,” Proceedings of 5th European Thermal-Sciences Conference, Eindhoven, The Netherlands, 2008. [2] L. Zhang, E.N.Wang, K.E. Goodson, and T.W. Kenny "Phase change phenomena in silicon microchannels,” International journal of heat and mass transfer, 48, pp. 1572-1582, 2005. [3] J.E. Kennedy, G.M. Roach Jr., M.F. Dowling, S.I. Abdel-Khalik S.M. Ghiaasiaan, S.M. Jeter, Z.H. Quershi, "The onset of flow instability in uniformly heated horizontal microchannels,” Journal of Heat Transfer, 122(1), p.p. 118-125, 2000. [4] K. Cornwell, P.A. Kew, "Boiling in small parallel channels,” Proceedings of CEC Conference on Energy Efficiency in Process Technology, Athens,Greece, 1992. [5] S.G. Kandlikar, "Heat transfer mechanisms during flow boiling in microchannels,” Journal of heat transfer, 126, pp. 8-16, 2004. [6] D. Brutin, L. Tadrist, "Pressure drop and heat transfer analysis of flow boiling in a minichannel: influence of the inlet condition on two-phase flow stability,” International journal of heat and mass transfer, 47, pp. 2365–2377, 2004. [7] D. Brutin, F. Topin, L. Tadrist, "Experimental study of unsteady convective boiling in heated minichannels,” International journal of heat and mass transfer, 46, pp. 2957–2965, 2003. [8] M. Ledinegg, "Instability of flow during natural and forced circulation,” Wärme, 61(8), pp. 891–898, 1938. [9] P.S. Ramesh, K.E. Torrance, "Stability of boiling in porous media,” International Journal of Heat and Mass Transfer 33(9) , pp. 1895-1908, 1990. [10] P.S. Ramesh, K.E. Torrance, "Boiling in a porous layer heated from below: effects of natural convection and a moving liquid/two-phase interface,” Journal of Fluid Mechanics 257, pp. 289-309, 1993. [11] D. Stemmelen, C. Moyne, A. Degiovanni, "Unstable boiling state in a porous medium,” Institution of Chemical Engineers Symposium Series 2(129) , pp. 1131-1137, 1992. [12] A. Sahli, C. Moyne, D. Stemmelen, "Boiling stability in a porous medium heated from below,” Transport in porous media, 82(3), pp. 527- 545, 2010. [13] W. Nakayama, T. Daikoku, T. Nakajima "Effects of pore diameters and system pressure on saturated pool nucleate boiling heat transfer from porous surfaces,” Journal of Heat Transfer 104(2), p.p. 286-292, 1982. [14] S. Mori, K. Okuyama "Enhancement of the critical heat flux in saturated pool boiling using honeycomb porous media,” International Journal of Multiphase Flow 35(10), p.p. 946–951, 2009. [15] S. Ghosh, T.K. Mandal, G. Das, P.K Das ”Review of oil water core annular flow,” Renewable and Sustainable Energy Reviews 13(8),p.p. 1957–1965, 2009. [16] M.E. Nakla, D.C. Groeneveld, S.C. Cheng "Experimental stufdy of inverted annular film boiling in a vertical tube cooled by R- 134a”Internaltional Journal of Multiphase Flow, 37(1), pp. 67-75, 2011. [17] T. Takamasa, T. Hazuku, T. Hibiki "Experimental study of gas-liquid two-phase flow affected by wall surface wettability” Internaltional journal of heat and fluid flow, 29(6), pp. 1593-1602, 2008. [18] D. Huh, C.H. Kuo, J.B. Grottberg, S. Takayama "Gas-Liquid two-phase flowpatterns in rectangular microchannels: effect of surface wetting properties,” New journal of physics, 11, 2009. [19] J.H. Yan, T.S. Laker, S.M. Ghiaasiaan "Linear stability of inverted annular gas-liquid two-phase flow in capillaries” International journal of heat and fluid flow, 24(1), pp. 122-129, 2003.
[1] C.M. Rops, L.F.G. Geers, J. Westerweel, "Explosive bubble growth during flow boiling in micro-channels,” Proceedings of 5th European Thermal-Sciences Conference, Eindhoven, The Netherlands, 2008. [2] L. Zhang, E.N.Wang, K.E. Goodson, and T.W. Kenny "Phase change phenomena in silicon microchannels,” International journal of heat and mass transfer, 48, pp. 1572-1582, 2005. [3] J.E. Kennedy, G.M. Roach Jr., M.F. Dowling, S.I. Abdel-Khalik S.M. Ghiaasiaan, S.M. Jeter, Z.H. Quershi, "The onset of flow instability in uniformly heated horizontal microchannels,” Journal of Heat Transfer, 122(1), p.p. 118-125, 2000. [4] K. Cornwell, P.A. Kew, "Boiling in small parallel channels,” Proceedings of CEC Conference on Energy Efficiency in Process Technology, Athens,Greece, 1992. [5] S.G. Kandlikar, "Heat transfer mechanisms during flow boiling in microchannels,” Journal of heat transfer, 126, pp. 8-16, 2004. [6] D. Brutin, L. Tadrist, "Pressure drop and heat transfer analysis of flow boiling in a minichannel: influence of the inlet condition on two-phase flow stability,” International journal of heat and mass transfer, 47, pp. 2365–2377, 2004. [7] D. Brutin, F. Topin, L. Tadrist, "Experimental study of unsteady convective boiling in heated minichannels,” International journal of heat and mass transfer, 46, pp. 2957–2965, 2003. [8] M. Ledinegg, "Instability of flow during natural and forced circulation,” Wärme, 61(8), pp. 891–898, 1938. [9] P.S. Ramesh, K.E. Torrance, "Stability of boiling in porous media,” International Journal of Heat and Mass Transfer 33(9) , pp. 1895-1908, 1990. [10] P.S. Ramesh, K.E. Torrance, "Boiling in a porous layer heated from below: effects of natural convection and a moving liquid/two-phase interface,” Journal of Fluid Mechanics 257, pp. 289-309, 1993. [11] D. Stemmelen, C. Moyne, A. Degiovanni, "Unstable boiling state in a porous medium,” Institution of Chemical Engineers Symposium Series 2(129) , pp. 1131-1137, 1992. [12] A. Sahli, C. Moyne, D. Stemmelen, "Boiling stability in a porous medium heated from below,” Transport in porous media, 82(3), pp. 527- 545, 2010. [13] W. Nakayama, T. Daikoku, T. Nakajima "Effects of pore diameters and system pressure on saturated pool nucleate boiling heat transfer from porous surfaces,” Journal of Heat Transfer 104(2), p.p. 286-292, 1982. [14] S. Mori, K. Okuyama "Enhancement of the critical heat flux in saturated pool boiling using honeycomb porous media,” International Journal of Multiphase Flow 35(10), p.p. 946–951, 2009. [15] S. Ghosh, T.K. Mandal, G. Das, P.K Das ”Review of oil water core annular flow,” Renewable and Sustainable Energy Reviews 13(8),p.p. 1957–1965, 2009. [16] M.E. Nakla, D.C. Groeneveld, S.C. Cheng "Experimental stufdy of inverted annular film boiling in a vertical tube cooled by R- 134a”Internaltional Journal of Multiphase Flow, 37(1), pp. 67-75, 2011. [17] T. Takamasa, T. Hazuku, T. Hibiki "Experimental study of gas-liquid two-phase flow affected by wall surface wettability” Internaltional journal of heat and fluid flow, 29(6), pp. 1593-1602, 2008. [18] D. Huh, C.H. Kuo, J.B. Grottberg, S. Takayama "Gas-Liquid two-phase flowpatterns in rectangular microchannels: effect of surface wetting properties,” New journal of physics, 11, 2009. [19] J.H. Yan, T.S. Laker, S.M. Ghiaasiaan "Linear stability of inverted annular gas-liquid two-phase flow in capillaries” International journal of heat and fluid flow, 24(1), pp. 122-129, 2003.
@article{"International Journal of Engineering, Mathematical and Physical Sciences:58353", author = "Cor M. Rops and Giaco C. Oosterbaan and Cees W.M. v/d Geld", title = "Operation Stability Enhancement in Once-Through Micro Evaporators", abstract = "Equipment miniaturisation offers several opportunities such as an increased surface-to-volume ratio and higher heat transfer coefficients. However, moving towards small-diameter channels demands extra attention to fouling, reliability and stable operation of the system. The present investigation explores possibilities to enhance the stability of the once-through micro evaporator by reducing its flow boiling induced pressure fluctuations. Experimental comparison shows that the measured reduction factor approaches a theoretically derived value. Pressure fluctuations are reduced by a factor of ten in the solid conical channel and a factor of 15 in the porous conical channel. This presumably leads to less backflow and therefore to a better flow control.
", keywords = " Flow boiling, Operation stability, Microfluidics, Microchannels.", volume = "7", number = "8", pages = "1310-7", }
