Investigation of Increasing the Heat Transfer from Flat Surfaces Using Boundary Layer Excitation
The present study is concerned with effect of exciting
boundary layer on increase in heat transfer from flat surfaces. As any
increase in heat transfer between a fluid inside a face and another one
outside of it can cause an increase in some equipment's efficiency, so
at this present we have tried to increase the wall's heat transfer
coefficient by exciting the fluid boundary layer. By a collision
between flow and the placed block at the fluid way, the flow pattern
and the boundary layer stability will change. The flow way inside the
channel is simulated as a 2&3-dimensional channel by Gambit
TM
software.
With studying the achieved results by this simulation for the flow
way inside the channel with a block coordinating with Fluent
TM
software, it's determined that the figure and dimensions of the exciter
are too important for exciting the boundary layer so that any increase
in block dimensions in vertical side against the flow and any
reduction in its dimensions at the flow side can increase the average
heat transfer coefficient from flat surface and increase the flow
pressure loss. Using 2&3-dimensional analysis on exciting the flow at
the flow way inside a channel by cylindrical block at the same time
with the external flow, we came to this conclusion that the heat flux
transferred from the surface, is increased considerably in terms of the
condition without excitation. Also, the k-e turbulence model is used.
[1] Jafari Nasr, M.R. and Polley, G.T., "An algorithm for cost comparison
of optimized shell and tube heat exchanger with tube insert and plain
tubes", Chem. Eng. Tech., Vol.23, pp.267-272, 2000.
[2] Tijing, L.D., Pak, B.C., "A study on heat transfer enhancement using
straight and twisted internal fin inserts", International Communications
in Heat and Mass Transfer, xx (2006) xxx-xxx.
[3] Drust,.F., and Becker,S., FY, "Boundary layer transition included by a
roughness element", international report, University Erlangen,
Germany, INEEL LDRD Program, 1973.
[4] Chiriac, Y.A. and Ortega, A., "A numerical study of the unsteady flow
and heat transfer in a transitional confined slot jot impinging on a
isothermal surface", Int., j., heat and mass transfer. Vol.45, pp1237-
1248, 2002.
[5] Kahrom M., Haghparast P., Javadi M., "Neural Network Application
in Boundary Layer Phenomenon for Cooling the Turbine Blades to
Improve the Cooling Process", 16th International Conference on
Mechanical Engineering, Iran, 2008.
[6] Beredberg, J., "Turbulence Modeling For Internal Cooling Gas -
Turbine Blades", PhD Thesis, Chalmers University of Technology,
Sweden, 2002.
[7] Ghobadi, A., Kahrom, M., "Cooling Turbine Blades using Exciting
Boundary Layer", International conference on computational and
mathematical engineering, Penang, Malaysia, 2010.
[8] B. E. Launder, D. B. Spalding. "Lectures in Mathematical Models of
Turbulence", Academic Press., London, England, 1972.
[9] T.B Gatski, M.Y.Hussaini, J.L. Lumley, "Simulation and Modeling of
Turbulent flows", Oxford University Press, New York, 1996.
[10] "Fluent User-s Guide", Version 4.3, vols, 1-4, Fluent Incorporated,
Lebanon, NH, 1995.
[11] S. V. Patankar, "Numerical Heat Transfer and Fluid Flow", McGraw-
Hill, 1980.
[1] Jafari Nasr, M.R. and Polley, G.T., "An algorithm for cost comparison
of optimized shell and tube heat exchanger with tube insert and plain
tubes", Chem. Eng. Tech., Vol.23, pp.267-272, 2000.
[2] Tijing, L.D., Pak, B.C., "A study on heat transfer enhancement using
straight and twisted internal fin inserts", International Communications
in Heat and Mass Transfer, xx (2006) xxx-xxx.
[3] Drust,.F., and Becker,S., FY, "Boundary layer transition included by a
roughness element", international report, University Erlangen,
Germany, INEEL LDRD Program, 1973.
[4] Chiriac, Y.A. and Ortega, A., "A numerical study of the unsteady flow
and heat transfer in a transitional confined slot jot impinging on a
isothermal surface", Int., j., heat and mass transfer. Vol.45, pp1237-
1248, 2002.
[5] Kahrom M., Haghparast P., Javadi M., "Neural Network Application
in Boundary Layer Phenomenon for Cooling the Turbine Blades to
Improve the Cooling Process", 16th International Conference on
Mechanical Engineering, Iran, 2008.
[6] Beredberg, J., "Turbulence Modeling For Internal Cooling Gas -
Turbine Blades", PhD Thesis, Chalmers University of Technology,
Sweden, 2002.
[7] Ghobadi, A., Kahrom, M., "Cooling Turbine Blades using Exciting
Boundary Layer", International conference on computational and
mathematical engineering, Penang, Malaysia, 2010.
[8] B. E. Launder, D. B. Spalding. "Lectures in Mathematical Models of
Turbulence", Academic Press., London, England, 1972.
[9] T.B Gatski, M.Y.Hussaini, J.L. Lumley, "Simulation and Modeling of
Turbulent flows", Oxford University Press, New York, 1996.
[10] "Fluent User-s Guide", Version 4.3, vols, 1-4, Fluent Incorporated,
Lebanon, NH, 1995.
[11] S. V. Patankar, "Numerical Heat Transfer and Fluid Flow", McGraw-
Hill, 1980.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:55605", author = "M.H.Ghaffari", title = "Investigation of Increasing the Heat Transfer from Flat Surfaces Using Boundary Layer Excitation", abstract = "The present study is concerned with effect of exciting
boundary layer on increase in heat transfer from flat surfaces. As any
increase in heat transfer between a fluid inside a face and another one
outside of it can cause an increase in some equipment's efficiency, so
at this present we have tried to increase the wall's heat transfer
coefficient by exciting the fluid boundary layer. By a collision
between flow and the placed block at the fluid way, the flow pattern
and the boundary layer stability will change. The flow way inside the
channel is simulated as a 2&3-dimensional channel by Gambit
TM
software.
With studying the achieved results by this simulation for the flow
way inside the channel with a block coordinating with Fluent
TM
software, it's determined that the figure and dimensions of the exciter
are too important for exciting the boundary layer so that any increase
in block dimensions in vertical side against the flow and any
reduction in its dimensions at the flow side can increase the average
heat transfer coefficient from flat surface and increase the flow
pressure loss. Using 2&3-dimensional analysis on exciting the flow at
the flow way inside a channel by cylindrical block at the same time
with the external flow, we came to this conclusion that the heat flux
transferred from the surface, is increased considerably in terms of the
condition without excitation. Also, the k-e turbulence model is used.", keywords = "Cooling, Heat transfer, Turbulence, Excitingboundary layer.", volume = "4", number = "12", pages = "1393-9", }