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# International Communications in Heat and Mass Transfer (v.32, #1-2)

Reduction in the surface tension of water due to physical water treatment for fouling control in heat exchangers by Young I. Cho; Sung-Hyuk Lee (

*pp. 1-9*).

**Keywords:** Physical water treatment; Surface tension; Dye-flow visualization

Forced convection in a composite parallel plate channel: modeling the effect of interface roughness and turbulence utilizing a

*k*â€“

*Îµ*model by J. Zhu; A.V. Kuznetsov (

*pp. 10-18*).

*k*â€“

*Îµ*model. Numerical results obtained utilizing both models are compared and analyzed in detail.

**Keywords:** Turbulence; Porous media; *k*; â€“; *Îµ*; model; Rough interface

Computational analysis of the feasibility of a micro-pulsejet by Qun Wan; W.L. Roberts; A.V. Kuznetsov (

*pp. 19-26*).

**Keywords:** Pulsejet; Micro-size engine; Pulse combustion; Numerical modeling

Pool boiling of saturated FC-72 on nano-porous surface by Srinivas Vemuri; Kwang J. Kim (

*pp. 27-31*).

_{2}O

_{3}) obtained from Whatman, were compared to that of a plain surface (aluminum) of thickness about 105 Î¼m. From the experimental data obtained it was evident that there is a reduction of about 30% in the incipient superheat for the applied power for nano-porous surface over plain surface. SEM photographs of the nano-porous coating were taken for determining the size of the pores.

**Keywords:** Pool boiling; Nano-porous surface; Enhanced surface

Weakly non-linear stability of stratified natural convection in a vertical cavity with lateral temperature gradient by M. Prud'homme; H. Bougherara (

*pp. 32-42*).

**Keywords:** Vertical stability; Stratification; Lateral temperature gradient

Inverse determination of a heat source from a solute concentration generation model in porous medium by S. Jasmin; M. Prud'homme (

*pp. 43-53*).

^{5}.

**Keywords:** Inverse convection; Porous medium; Biochemical heat source

Stability of gravitactic micro-organisms in a fluid-saturated porous medium by T. Nguyen-Quang; A. Bahloul; T.H. Nguyen (

*pp. 54-63*).

*V*

_{c}. The resulting equilibrium state is potentially unstable as a denser layer of micro-organisms is formed on top of a lighter one. The basic mechanism is analogous to that of BÃ©nard convection in a fluid layer heated from below. The fluid flow is governed by the Darcy equation while the conservation of micro-organisms is described by a diffusionâ€“convection equation similar to the conservation of energy. The problem depends on two parameters, namely the Rayleigh number and the swimming velocity

*V*

_{c}. The present paper is focused on the stability of the equilibrium diffusive state. The stability diagram and the critical conditions for the onset of convection are obtained for a wide range of swimming velocity. It is found that if

*V*

_{c}is very small, the critical wavenumber is zero, corresponding to a very long cell (parallel flow), but as

*V*

_{c}is increased, the critical wavenumber also increases, corresponding to narrower flow patterns.

**Keywords:** Bioconvention; Gravitactic micro-organisms; Porous medium; Stability

Bioconvection of gravitactic microorganisms in a fluid layer by A. Bahloul; T. Nguyen-Quang; T.H. Nguyen (

*pp. 64-71*).

**Keywords:** Bioconvection; Stability; Fluid medium; Gravitactic micro-organism

Near-wall velocity profile with adaptive shape functions for turbulent forced convection by P.S. Glockner; G.F. Naterer (

*pp. 72-79*).

*k*âˆ’

*É›*turbulence model.

**Keywords:** Reichardt's Law; Turbulent channel flow; CVFEM

Moisture transfer models for slabs drying by E. Kavak Akpinar; I. Dincer (

*pp. 80-93*).

**Keywords:** Drying; Moisture transfer; Moisture diffusion; Models; Slab

Suppressing natural convection in a differentially heated square cavity with an arc shaped baffle by Syeda Humaira Tasnim; Michael R. Collins (

*pp. 94-106*).

**Keywords:** Baffle; Energy transfer; Finite volume method; Natural convection; Nusselt number

Turbulent kinetic energy distribution across the interface between a porous medium and a clear region by Marcelo J.S. de Lemos (

*pp. 107-115*).

**Keywords:** Interface; Jump conditions; Turbulence; Porous media; Environmental flows

Critical size of aerosol particles in the resonance radiation field by V.V. Levdansky; J. Smolik; P. Moravec (

*pp. 116-122*).

**Keywords:** Aerosol particle; Condensation; Critical size

On heat conduction problem in a semi-infinite periodically laminated layer by Roman Kulchytsky-Zhyhailo; StanisÅ‚aw J. Matysiak (

*pp. 123-132*).

*n*periodically repeated two-layered, perfect bonding lamine. The problem is solved on two ways: (1) directly as heat conduction problem or (2) by using the homogenized model with microlocal parameters [R. Kulchytsky-Zhyhailo, S.J. Matysiak, On some heat conduction problem in a periodically two-layered body. Comparative results, Int. Commun. Heat Mass Transf., in press]. The obtained results are compared and presented in the form of figures.

**Keywords:** Laminated composite; Temperature; Heat flux; Semi-infinite layer; Homogenized model

Correlated radiative transfer through a packed bed of opaque spheres by Kouichi Kamiuto; San San Yee (

*pp. 133-139*).

*S*

_{r}to the extinction coefficient of packed spheres empirically determined by Singh and Kaviany closely resembles the scaled extinction enhancement factor (2

*Î³*

_{2}âˆ’1) theoretically derived by Kamiuto, except in a low porosity region.

**Keywords:** Correlated radiative transfer; Packed bed; Opaque sphere; Hemispherical transmittance

Effect of porous media on the performance of the double-pass flat plate solar air heater by Paisarn Naphon (

*pp. 140-150*).

**Keywords:** Porous media; Performance; Double-pass solar air heater

Air side performance at low Reynolds number of cross-flow heat exchanger using crimped spiral fins by A. Nuntaphan; T. Kiatsiriroat; C.C. Wang (

*pp. 151-165*).

**Keywords:** Heat exchanger; Performance testing; Crimped spiral fins

Effect of protrusion on thermal transient behavior of chips in a liquid channel during loss of pumping power by H. Bhowmik; K.W. Tou (

*pp. 166-174*).

^{2}to 7 W/cm

^{2}. The general impacts of heat source protrusions (

*B*=1, 2 mm) on heat transfer behavior of four chips are investigated by comparing the results obtained from flush-mounted (

*B*=0) heat sources. Finally the correlation equations are obtained by modifying the correlations of flush-mounted heater, employing the chips' protrusion height (

*B*) in the dimensionless (

*B*/â„“) form.

**Keywords:** Discrete heat source; Electronic cooling; Natural convection; Transient heat transfer

Condensation of steam in silicon microchannels by Yongping Chen; Ping Cheng (

*pp. 175-183*).

^{2}at Î”

*T=*10 Â°C in a microchannel having a hydraulic diameter of 75 Î¼m.

**Keywords:** Condensation; Microchannel; Phase change

Numerical simulation of heat transfer in a desktop computer with heat-generating components by J.S. Chiang; S.H. Chuang; Y.K. Wu; H.J. Lee (

*pp. 184-191*).

**Keywords:** Desktop computer; Computational fluid dynamics; Heat transfer

Effect of a non-uniform basic temperature gradient on the onset of Bénard-Marangoni convection: Stationary and oscillatory analyses by Ko-Ta Chiang (

*pp. 192-203*).

*C*) is a clearly destabilizing factor, but the conductive effect (i.e.,

*a*

_{ i}* of non-steady conditions within the fluid layer does play a stabilizing state. The system becomes more stable at larger values of the Prandtl number

*Pr*, the Biot number

*B*

_{ i}and the Bond number

*B*

_{ o}. We obtain a set of characteristic curves in the (

*M*

_{C},

*R*)-plane that satisfy the linear relation on the onset of the stationary and oscillatory Bénard-Marangoni convective instability.

**Keywords:** Crispation; Stationary; Oscillatory; Convective instability

An integral approach for hydromagnetic natural convection heat and mass transfer from vertical surfaces with power-law variation in wall temperature and concentration in porous media by Ching-Yang Cheng (

*pp. 204-213*).

**Keywords:** Hydromagnetic natural convection heat; Heat and mass transfer; Power-law variation

Entropy generation and thermodynamic optimization of fully developed laminar convection in a helical coil by T.H. Ko; K. Ting (

*pp. 214-223*).

*Re*), coil-to-tube radius ratio (

*Î´*) and nondimensional coil pitch (

*Î»*) are varied to investigate their influences on the entropy generation. The results presented in this paper cover

*Re*range of 100â€“10,000,

*Î´*and

*Î»*range from 0.01 to 0.3. Compared with

*Re*and

*Î´*, the coil pitch

*Î»*is found to have minor influence on the entropy generation. For a demonstrated case, the minimum entropy generation occurs in the range bounded by

*Re*from 2271 to 4277 and

*Î´*from 0.17 to 0.3, within which the irreversibility of the system is lowest and the system performance would be optimum. The details show that there is an optimal

*Re*for a helical coil with a fixed

*Î´*; meanwhile for a helical coil flow with a specified

*Re*, the smaller

*Î´*should be selected when the

*Re*is larger than 5000, and the larger

*Î´*should be selected when the

*Re*is less than 5000. These results provide worthwhile information for heat exchanger designers to find the optimal helical coil design from the viewpoint of the thermodynamic second law.

**Keywords:** Entropy generation; Helical coil; Irreversibility; Thermodynamic second law

Fluid flow and heat transfer in fluidized bed vertical shell and tube type heat exchanger by S.W. Ahn; S.T. Bae; B.C. Lee; W.C. Kim; M.W. Bae (

*pp. 224-232*).

**Keywords:** Fluidized bed type; Heat exchanger; Solid particles; Heat transfer coefficient; Counterflow

Film condensations of flowing mixtures of steam and air on an inclined flat plate by Bum-Jin Chung; Sin Kim; Min Chan Kim (

*pp. 233-239*).

**Keywords:** Condensation; Film-wise condensation; Inclined plate; Plate orientation; Stem; Air

Effect of a longitudinally positioned solenoid coil on electronic descaling by C.H. Sohn; C.S. Kim; S.Y. Moon; Y.I. Cho (

*pp. 240-247*).

**Keywords:** Electronic descaling; Solenoid coil

An experimental study on convection heat transfer from an array of discrete heat sources by S. Baskaya; U. Erturhan; M. Sivrioglu (

*pp. 248-257*).

*Re*

*D*

_{h}â‰¤7955, and modified Grashof numbers

*Gr**=1.72Ã—10

^{8}to 2.76Ã—10

^{9}. From the experimental measurements, surface temperature distributions of the discrete heat sources were obtained and effects of Reynolds and Grashof numbers on these temperatures were investigated. Furthermore, Nusselt number distributions were calculated for different Reynolds and Grashof numbers. Results show that surface temperatures increase with increasing Grashof number and decrease with increasing Reynolds number. However, with the increase in the buoyancy affected secondary flow and the onset of instability, temperatures level off and even drop as a result of heat transfer enhancement. This outcome can also be observed from the variation of the row-averaged Nusselt number showing an increase towards the exit.

**Keywords:** Convection heat transfer; Discrete heat sources

Effects of non-Darcian on forced convection heat transfer over a flat plate in a porous medium-with temperature dependent viscosity by M.A. Seddeek (

*pp. 258-265*).

**Keywords:** Non-Darcian; Forced convection; Heat transfer; Porous medium

Effective parameters on second law analysis for semicircular ducts in laminar flow and constant wall heat flux by Hakan F. Oztop (

*pp. 266-274*).

**Keywords:** Second law analysis; Laminar flow; Semi-circular duct

Experimental study of heat transfer enhancement in an asymmetrically heated rectangular duct with perforated baffles by Rajendra Karwa; B.K. Maheshwari; Nitin Karwa (

*pp. 275-284*).

**Keywords:** Heat transfer enhancement; Rectangular duct with baffles; Thermo-hydraulic performance