Numerical Solution for Transient Conjugate Two-Phase Heat Transfer With Heat Generation in the Pipe Wall

Yuri V. Fairuzov; Hector Arvizu

doi:10.1115/1.1470170

Numerical Solution for Transient Conjugate Two-Phase Heat Transfer With Heat Generation in the Pipe Wall

Journal of Heat Transfer ◽

10.1115/1.1470170 ◽

2002 ◽

Vol 124 (6) ◽

pp. 1213-1218 ◽

Cited By ~ 1

Author(s):

Yuri V. Fairuzov ◽

Hector Arvizu

Keyword(s):

Heat Transfer ◽

Numerical Solution ◽

Heat Generation ◽

Two Phase ◽

Convective Boiling ◽

Wall Superheat ◽

Boiling Flow ◽

Rigorous Model ◽

Two Phase Heat Transfer ◽

Transient Boiling

A method developed earlier for modeling conjugate two-phase heat transfer in flashing flows was used to obtain a numerical solution for transient boiling flow in heated pipes or channels. Two criteria of applicability of the solution obtained were proposed and numerically tested using a more rigorous model, which accounts for the effects of heat conduction with heat generation in the wall and forced convective boiling. The solution obtained provides a simple and reliable alternative to more rigorous methods for modeling transient two-phase flow in heated channels when the material of the wall bounding the flow has a high thermal conductivity and the wall superheat is small.

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Reduced Pressure Boiling Heat Transfer in Rectangular Microchannels With Interconnected Reentrant Cavities

Journal of Heat Transfer ◽

10.1115/1.2035107 ◽

2005 ◽

Vol 127 (10) ◽

pp. 1106-1114 ◽

Cited By ~ 57

Author(s):

Ali Koşar ◽

Chih-Jung Kuo ◽

Yoav Peles

Keyword(s):

Heat Transfer ◽

Heat Fluxes ◽

Transfer Coefficients ◽

Two Phase ◽

Convective Boiling ◽

Reduced Pressure ◽

Exit Pressure ◽

Mass Fluxes ◽

Mechanism Transition ◽

Two Phase Heat Transfer

Boiling flow of deionized water through 227μm hydraulic diameter microchannels with 7.5μm wide interconnected reentrant cavities at 47 kPa exit pressure has been investigated. Average two-phase heat transfer coefficients have been obtained over effective heat fluxes ranging from 28 to 445W∕cm2 and mass fluxes from 41 to 302kg∕m2s. A map is developed that divides the data into two regions where the heat transfer mechanisms are nucleation or convective boiling dominant. The map is compared to similar atmospheric exit pressure data developed in a previous study. A boiling mechanism transition criterion based on the Reynolds number and the Kandlikar k1 number is proposed.

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Numerical Simulation of Transient Boiling Convection in Microchannels

Heat Transfer: Volume 2 ◽

10.1115/ht2003-47300 ◽

2003 ◽

Cited By ~ 2

Author(s):

D. W. Fogg ◽

J. M. Koo ◽

L. Jiang ◽

K. E. Goodson

Keyword(s):

Heat Exchangers ◽

Energy Transport ◽

Pressure Fluctuations ◽

Bubble Nucleation ◽

Transient Pressure ◽

Two Phase ◽

Convective Boiling ◽

Periodic Distribution ◽

Wall Superheat ◽

Transient Boiling

Two-phase microchannel heat exchangers are receiving increasing attention from the microprocessor industry as power density levels in microchips increase. Previous numerical investigations of convective boiling in microchannels assumed steady flow within the channels. However, experimental data shows that two-phase flows in microchannels are highly transient even under steady heat loads. Little work has been done to model the dynamics associated with vapor generation in microchannels. The present work simulates the periodic distribution of vapor within microchannels filled with water by solving one-dimensional homogeneous equations for the mass, momentum and energy transport in conjunction with a transient wall conduction equation. A wall superheat constraint is incorporated to account for the excess superheat temperature required for bubble nucleation. Boiling events reduce the local wall temperature and change the pressure and enthalpy distributions within the flow. The transient pressure fluctuations predicted here are consistent with those observed in experiments. This study provides insight into the significance of bubble nucleation for forced convective boiling in microchannels and will be useful for the optimization of microchannel heat exchangers.

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Heat Transfer in Two-Component Dispersed Flow

Journal of Heat Transfer ◽

10.1115/1.3244457 ◽

1981 ◽

Vol 103 (2) ◽

pp. 300-306 ◽

Cited By ~ 27

Author(s):

K. Mastanaiah ◽

E. N. Ganic´

Keyword(s):

Heat Transfer ◽

Wall Temperature ◽

Gas Flow ◽

Steel Tube ◽

Stainless Steel Tube ◽

Two Phase ◽

Dispersed Flow ◽

Wall Superheat ◽

Two Phase Heat Transfer ◽

Thermal Entrance

Measurements have been made of heat transfer near atmospheric pressure in the post dryout region of air-water dispersed flow in an electrically heated 12.95 mm i.d. vertical stainless steel tube with a length of 889 mm. The mass velocity ranges from 30 to 83 kg/m2·s, and the average wall heat flux is varied from 6.4 to 36.2 kW/m2 in the experiments. Correlation of a theoretical analysis with the measured wall temperatures suggests that the effectiveness of wall-to-drop heat transfer depends mainly on the wall superheat for surface temperatures below the minimum film boiling temperature. The local two-phase heat transfer coefficient decreases with increasing wall temperature. It is also found that the thermal entrance length for two-phase dispersed flow exceeds that of the single-phase gas flow, and that it decreases with an increase in wall temperature.

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Boiling Heat Transfer From a Horizontal Tube in an Upward Flowing Two-Phase Crossflow

Journal of Heat Transfer ◽

10.1115/1.3246762 ◽

1984 ◽

Vol 106 (4) ◽

pp. 849-855 ◽

Cited By ~ 11

Author(s):

M. E. Wege ◽

M. K. Jensen

Keyword(s):

Heat Transfer ◽

Vertical Channel ◽

Horizontal Tube ◽

Nucleate Boiling ◽

Working Fluid ◽

Transfer Coefficients ◽

Two Phase ◽

Average Deviation ◽

Wall Superheat ◽

Two Phase Heat Transfer

An experimental investigation has been performed to determine the effects of a low-quality (≤ 20 percent) upward flowing mixture on the nucleate boiling on a single horizontal lube. An electrically heated, 12.7-mm-dia tube was centered in a plane wall vertical channel, the width of which resulted in channel width-to-tube diameter ratios (w/d) of 1.16 and 1.95. The working fluid was R-113. The two-phase heat transfer data showed a variety of effects. For a fixed w/d, pressure (P), and quality (x), the average heat transfer coefficients (h) increased with increasing mass velocity (G), but the effect of G decreased as the wall superheat (ΔT) increased. For a fixed w/d, G and x, h increased as the pressure increased except at low ΔT’s where the reverse was found. For fixed w/d, P and G, h increased with increasing quality with the effect appearing to be more pronounced at the lower pressure. At a fixed P, G and x, h was at larger w/d ratios at small ΔT’s, but as the wall superheat increased an inversion occured and h became smaller at the larger w/d ratio. The behavior exhibited in this experiment can be explained in terms of the velocity of the fluid flowing past the test section. The data were successfully predicted to within an average deviation of ±11.6 percent using a Chen-type correlation. Data from the literature also were predicted well.

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Phenomenological correlations for two phase heat transfer and pressure drop performance of electrohydrodynamic horizontal convective boiling of dielectric fluids

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2018.12.019 ◽

2019 ◽

Vol 132 ◽

pp. 1018-1028 ◽

Cited By ~ 2

Author(s):

S. Nangle-Smith ◽

J.S. Cotton

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Two Phase ◽

Convective Boiling ◽

Dielectric Fluids ◽

Two Phase Heat Transfer

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Convective Boiling in Vertical Channels With Different Offset Strip Fin Geometries

Journal of Heat Transfer ◽

10.1115/1.3250638 ◽

1989 ◽

Vol 111 (1) ◽

pp. 156-165 ◽

Cited By ~ 34

Author(s):

G. D. Mandrusiak ◽

V. P. Carey

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Film Flow ◽

Nucleate Boiling ◽

Two Phase ◽

Wall Superheat ◽

Annular Film ◽

Two Phase Heat Transfer ◽

Offset Strip Fin

Newly obtained local heat transfer data are presented for flow boiling of liquids in two partially heated vertical channels with different offset strip fin geometries operating at low to moderate wall superheat levels. Experiments were conducted in special test sections that permitted direct visual observation of the boiling process while simultaneously measuring the heat transfer coefficient along the channel. Data for which nucleate boiling appeared to be completely suppressed were analyzed together with similar results for other offset fin geometries to assess the effects of channel geometry variations on the two-phase heat transfer coefficient during annular film-flow evaporation. For all geometries considered, the data for annular film-flow evaporation were found to correlate well in terms of modified versions of the F and Martinelli parameters used by Bennett and Chen (1980) to correlate similar data for round tubes. For fin matrices of similar size and configuration, the forced convective component of the two-phase heat transfer coefficient was found to be well represented by a single F-parameter correlation curve. However, F-factor correlations for matrices having significant differences in fin and channel dimensions were found to differ substantially. An approximate superposition method for including the contribution of nucleate boiling to the two-phase heat transfer coefficient at low to moderate wall superheat levels is also proposed.

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