Abstract
A new computation method is presented for the accurate determination of temperature fields and heat transfer characteristics for steady forced convection flow in coolant channels with an arbitrary prescribed wall heat flux. The essential feature of this method is that the fluid region is discretized in the section normal to the flow direction. Energy balances set up for each of the elements yield a system of linear first order differential equations with as a sole independent variable an axial distance parameter. This system of equations is solved analytically using a matrix method. The method is illustrated for the case of laminar flow in flat and circular ducts.
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Abbreviations
- a :
-
thermal diffusivity, λ c/ρc p.
- [A]:
-
symmetric tridiagonal matrix of dimensionless transport coefficients, eqs. (19–21)
- c p :
-
specific heat
- D :
-
dimensionless transport coefficient, eq. (16)
- d e :
-
equivalent hydraulic diameter
- d e·t :
-
equivalent thermal diameter
- G i :
-
elementary mass flow rate in an element i
- G t :
-
total mass flow rate
- GR i :
-
reduced elementary mass flow rate, eq. (15)
- H :
-
fluid enthalpy
- ΔH :
-
total fluid enthalpy rise over length of channel
- HR i :
-
dimensionless fluid enthalpy, eq. (10)
- L :
-
heated channel length
- N :
-
number of fluid elements in discretization procedure
- Nu :
-
local Nusselt number, αd e/λ, dimensionless
- Pe :
-
Peclet number, d e u b/a, dimensionless
- Q :
-
heat flow per unit of length
- QR i :
-
dimensionless heat generation term, eq. (17)
- q′ :
-
heat generation per unit of length
- q″ :
-
local heat flux
- s i·j :
-
lateral extent of boundary between adjacent fluid elements i and j
- T :
-
temperature
- u :
-
axial velocity
- [VE]:
-
eigenvector matrix
- x :
-
axial distance coordinate
- X :
-
dimensionless axial distance x/L
- y :
-
wall distance
- y 0 :
-
distance between wall and symmetry line
- Δy i :
-
width of grid element
- α :
-
heat transfer coefficient, eq. (47)
- β i·j :
-
local transport coefficient, eq. (4)
- γ i :
-
eigenvalue, dimensionless
- λ :
-
thermal conductivity of fluid
- ρ :
-
fluid density
- av:
-
averaged over heated channel length
- b:
-
bulk
- c:
-
channel centre, or adiabatic wall
- i :
-
number of fluid element
- in:
-
inlet
- w:
-
wall
- x :
-
axial position
References
Graetz, L., Ann. Phys. Chem. 25 (1885) 337.
Sellars, J. R., M. Tribus and J. S. Klein, Trans. Amer. Soc. Mech. Engrs. 78 (1956) 441.
Siegel, R., E. M. Sparrow and T. M. Hallman, Appl. Sci. Res. A7 (1957) 386.
Sparrow, E. M., T. M. Hallman and R. Siegel, Appl. Sci. Res. A7 (1957) 37.
Hsu, C. J., AIChE J. 11 (1965) 690.
Hatton, A. P. and A. Quarmby, Int. J. Heat Mass Transfer 6 (1963) 903.
Lundberg, R. E., P. A. McCuen and W. C. Reynolds, Int. J. Heat Mass Transfer 6 (1963) 495.
Hasegawa, S. and Y. Fujita, Int. J. Heat Mass Transfer 11 (1968) 943.
Chen, J. C. and W. S. Yu, Int. J. Heat Mass Transfer 13 (1970) 667.
Hasegawa, S. and Y. Fujita, 4th Int. Heat Transfer Conf., Paris, (1970) FC 3.4, 1.
Bankston, C. A. and D. M. McEligot, Nucl. Sci. Eng. 37 (1969) 157.
Nijsing, R., Heat Exchange and Heat Exchangers with Liquid Metals, in Lecture Series Nr. 57 on Heat Exchangers, AGARD, Paris 1972.
Kays, W. M., Trans. ASME 77 (1955) 1265.
Grigull, U. and H. Tratz, Int. J. Heat Mass Transfer 8 (1965) 669.
Buleev, N. I., L. D. El Tsova and C. P. Biryuka, High Temp. 4 (1966) 510.
Nijsing, R. and W. Eifler, Nucl. Eng. Design 4 (1966) 253.
Nijsing, R. and W. Eifler, Thermal Design Aspects of Fuel Rod Bundles with Emphasis on Intersubchannel Mixing, Deutsches Atomforum, Bonn (1971) 126–129.
Nijsing, R. and W. Eifler, A Computation Method for the Steady State Thermohydraulic Analysis of Fuel Rod Assemblies with Single Phase Cooling, to be published.
Nijsing, R. and W. Eifler, Nucl. Eng. Design 23 (1972) 331.
Schneider, P. J., Trans. ASME 79 (1957) 765.
Hsu, C. J., Appl. Sci. Res. 17 (1967) 359.
Hsu, C. J., Chem. Engng. Sci. 23 (1968) 457.
Hennecke, W., Wärme- und Stoffübertragung 1 (1968) 177.
Hsu, C. J., Int. J. Heat Mass Transfer 13 (1970) 1907.
Hsu, C. J., AIChE J. 17 (1971) 732.
Zurmühl, R., Matrizen, Springer, Göttingen, p. 144.
Wilkinson, J. H., The Algebraic Eigenvalue Problem, Clarendon Press, Oxford (1965).
Ralston, A. and H. S. Wilf, (ed.), Mathematical Methods for Digital Computers, Wiley & Sons, Inc., New York (1966).
Wilkinson, J. H., Numer. Math. 4 (1962) 354.
Rutishouser, H., and H. R. Schwarz, Numer. Math. 5 (1963) 273.
Galligani, I., A Comparison of Methods for Computing the Eigenvalues and Eigenvectors of a Matrix, EUR 4055 e (1968).
Lancaster, P., Theory of Matrices, Academic Press, New York (1969) p. 96.
Leveque, A., Ann. Mines, Paris — Mém. Sér. 12, 13 (1928) 283.
Kramers, H. and P. J. Kreyger, Chem. Eng. Science 6 (1956) 42.
Bird, R. B., W. E. Stewart and E. N. Lightfoot, Transport Phenomena, John Wiley & Sons, Inc., New York (1960) 363.
Worsøe-Schmidt, P. M., Int. J. Heat Mass Transfer 10 (1967) 541.
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Nijsing, R., Eifler, W. The hybrid method, a new method for accurate heat transfer predictions in channels with axially variable heat flux. Appl. Sci. Res. 28, 401–418 (1973). https://doi.org/10.1007/BF00413080
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DOI: https://doi.org/10.1007/BF00413080